Primitive Archer
Main Discussion Area => Horn Bows => Topic started by: DC on June 26, 2019, 03:25:09 pm
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I'm going to start this with a quote from Gorazd from the other thread.
The thinnest part will go on the siyahs... more important is enough thickness left in the bending part of the horn - there should be at least 5-6mm ... considering that you must sand both parts to be of the equal thickness along whole length. And during this sanding you will loose some thickness...
5-6mm,, that's just enough to make me think I can rip these strips in half. Dangerous thought. That 5-6 mm, what weight bow would that give or is the weight more determined by the thickness of the core?
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Considering the trouble that Mafort had straightening his horn should I bother trying to straighten this (almost) 1/2" thick horn. It would make it a lot easier to work on if it was straight(er)
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My advice is to thin it. I thinned it down to a quarter inch and then soaked for 2 days and boiled. Straightened out with no issues.
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When you were thinning it did you flatten the outside to a "finish surface" and then remove the bulk of the horn from the inner surface? One of the reasons I wanted to flatten it now was to make it easier to remove material from the inside on the belt sander.
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3 of the 4 strips I got have this little white stripe on the inside surface. Is this something I should be avoiding? Maybe do most of my grinding from this side to try and get past it. It's in the future centre of the limb so my selfbow brain tells me it's nothing to worry about but I'd better check.
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I've been reading that horn is hygroscopic. Does this mean an extended drying period is necessary after boiling? Is it worse than wood?
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Any scrap left over will be tip overlays, nock inserts, knife scales, inlays, etc! No sense wasting any of it!
Full disclosure: I only posted that comment in order to get notifications of further additions to this post. I really don't wish to miss any of this.
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So far it's just been a series of my questions ;D ;D. Here's another one spawned by JW's comment. The tips of the horn strip would make good ELB tips and some overlays. The tip of the horn goes in the handle. How wide is it likely to be there? I'm wondering how much of the tip I will be cutting off. I'd rather do it now while it's still full thickness.
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So far all I've done is try to straighten some full thickness horn with limited success. I'm slowly rereading all the posts in the "Horn Bows" section and searching the web for videos. I remember there was some posted by an Slavic gentleman who was making a horn bow in his kitchen, it looked like. They were good and I can't find them now. JWB bows has a bunch but they are very short. If anyone has any links they would like to share I would be pleased.
Your bell is going to be dinging regular JW :D :D
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Dry heat works well as I understand. I would take it down to a quarter inch and then use dry heat from a stove top to straighten it out. Go slow and be gentle. Have a friend or someone brush on some water while you’re straightening it up. I tied mine to a flat board and it retained a large amount of the straightening. I’ve got one more session to do today or tomorrow sometime and I’ll leave them be on the board till Sunday morning and then I’ll glue it to the core wood. I had a short elm stave that was good enough for the core.
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The horn bow I’m making is kind of a weird one. So hopefully it all works out
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Have you found that a boiled strip takes longer to get stiff again than a dry heated piece? I have one that I boiled and after a couple of days it still seems bendier than the ones I haven't done.
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Dry heat plasticizes the cells of the horn which may account for the stiffness. Which I don’t mind too much. I don’t know about boiling. All I know is I had a mother set of horns which I ended up turning into knock reinforcements for arrows and overlays. They boiled for 30 minutes and they were barely straight but it’s probably because of the thickness I had them at.
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Oh that sucks. How do you know they're ruined? Symptoms?
These are a few of the things I've been trying with varying degrees of success. Sometimes there is just no substitute for more clamps. I've avoided more than 10 min boiling and more than 250°f dry heat so hopefully I'm OK. I've got one to the point that I feel I can start running it through my thickness sander. I smoothed/flattened the outside but it's still curved. I'm hoping he thickness sander will work for the inside. Somehow all the write-ups I've found seem to gloss over this part. "Boil for 10 mins and bend straight" hardly covers it. :D
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Another question. I've read that when you heat tiller or heat the horn/core for any reason the horn will try and resume it's original shape. This makes sense. Does that mean that the horn strips have to be oriented so that if/when they do revert they will be adding reflex? This would mean that somehow you would have to mark the horn strip so that you don't lose track of which way is which. As long as you have a bit of the horn base showing you will be OK but if you were to make perfect rectangular strips it could be a problem.
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I’m not 100% sure on that question. That’s how I have mine setup.
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Yet another question. 3 piece and 5 piece. 5 piece would be two siyahs,2 limbs and a grip. 3 piece could be 2 siyahs and one piece for the limbs and grip or it could be the grip and 2 limbs complete with siyahs. Does it matter?
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Id go with the three. The two siyahs and the stave. If you can. Some find it easier to glue on the handle rather that glue a separate piece on.
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I bit the bullet and bought the Kindle version of Adam's book. A quick look through and a lot of it is like reading the answers to questions on this forum. I think a lot of the answers are direct quotes. Anyway there is a ton of info to go through and it seems to be shotgunned through the book. One measurement here and another 20 pages away. I have mostly figured out the dimensions so I'm making a full sized drawing to see how it comes together. First thing I noticed is that these things are small and the working limb is even smaller so you don't really need great long horns. I think my shortest horn will be 4-5 inches to long. I finally got the horn mostly(good enough) straightened. I thinned it down to 1/4"(like Mafort said). Instead of boiling I put the strips in a 250°f oven for 1/2 hour, clamped them between two boards and left them overnight to cool.
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I would take a pair of calipers and check to be 100%. If also still make your core 1/8” thick so that way you can scrape the horn away gently and get your draw weight. I am in no way an expert but that’s what I’m doing. I’d read that book and re read it to soak in all the information on it
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The horn is just roughed out now. I have to run it through the thickness sander to get rid of those little dips and then scrape it smooth. Long way to go yet. I'm kind of thinking I would put the horn on at 1/8-3/16" thick. I cut my laths and grip today. I'm going with 3 piece, grip and limbs as long as I don't mess up the limbs bending them. Limbs are Douglas Maple and the grip is Ocean Spray. Kind of a western Eastern bow. Here's some pictures of the pieces and my mock up. I used the limb of a Plum bow I'm making for the mock up. Did you find that the info was kind of shotgunned around that book?
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I wouldn’t know to be honest. I’ve never read it.
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I’d read that book and re read it to soak in all the information on it
Which book was this?
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Here's a picture of the caul I'm planning to bend my limbs around. I'll do a couple of test bends to see if I like the shape. I can do that while I'm waiting for the limbs to soak for a week!! That seems like a long soak but I guess it can't hurt. I've only got the two perfect? limb laths. No sense taking a chance.
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Yea that’s true and I was talking about the book or you mentioned earlier. To be honest I’m kinda winging this. I read the past posts as far back as I could on the horn bows section and I learned a lot of information about it
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I made a shortcut to avoid bending thick wood.
I made a form for turkish siyahs then glued 4 thinner strips (4mm thick) in form to match exact turkish look...
Here's a picture of the caul I'm planning to bend my limbs around. I'll do a couple of test bends to see if I like the shape. I can do that while I'm waiting for the limbs to soak for a week!! That seems like a long soak but I guess it can't hurt. I've only got the two perfect? limb laths. No sense taking a chance.
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Thank you for joining in. I was thinking that no one was reading this. I wondered about laminating after my first try at bending a piece of Hazel as a test. I got quite a bit of spring back. I hadn't soaked it for a week or dried it for a week but still. It would save me building a trough to boil it in. It would also save me a month in drying. Did you use epoxy or hide glue?
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I did laminating turkish siyahs with hide glue ...
I glued 4mm thick pieces of black locust. But before gluing - I did dry heat bending of the pieces to get some bends of the form - I heated with heat gun and fixed the laths (with the clamps) in the form , one by one...
And left in the form for one day - I guess that with thinner laths (3mm ) it should go without prebending. But I did it to avoid too much stress with glue line and risk of cracking wood...
When gluing - I precoated the wood couple of times with thin hide glue and finnaly with one thick (hot) hide glue - messy proces - when you join 4 pieces they get pretty slippery and some help is needed to fix them with clamps...
I did one pair of siyahs for mongol bow with epoxy glue too.... these still wait for next project (f)
Of course epoxy gluing is much much faster - I thickened the laminating resin with microbalons...
But regarding the strength - hide glue is very strong - I joined two pieces of black locust with just one thick hot hide glue layer and couple of weeks later later I hammer tested the joint.
No way to crack the glue joint - wood gave in - black locust tear out.
Obviously black locust is compatible with hide glue...
Thank you for joining in. I was thinking that no one was reading this. I wondered about laminating after my first try at bending a piece of Hazel as a test. I got quite a bit of spring back. I hadn't soaked it for a week or dried it for a week but still. It would save me building a trough to boil it in. It would also save me a month in drying. Did you use epoxy or hide glue?
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So you're doing 5 piece construction? I have my Douglas Maple all cut out for complete limbs(3 piece). I may just continue that to keep with the traditional way but at the same time I think I'll follow your lead and epoxy up some Eastern Maple strips into siyahs as backup in case the bending goes bad. I'm curious to see if the soaking/boiling method will produce a limb with little or no springback.
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Oh, when you say you are gluing up the siyahs with 4mm lams how much of the bow are you making? Will your siyahs include the tips and the entire kasan or will it just be the tip and the outer half of the kasan. Put another way will you have a slice in the middle of the kasan? Sorry for all the questions. :D
Nevermind I just found it in Adams book on a 5 piece the splice is in the kasan.
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I actually already have two natural Crabapple crooks that I can use for siyahs. I could epoxy up some limbs with the kasan eye bend out of the Eastern Maple. Hmmm
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The Crabapple crooks had too tight an angle and not a sharp enough bend so I decided to laminate a couple. It's 4 layers of Eastern(Sugar) Maple. I boiled them and clamped it up. It went very smoothly and looks real good. The pieces are 2" wide so I will rip them down the middle to get two identical siyahs. It will take a month of Sundays to dry I imagine but I've got a few years in me yet ;D I also put some Douglas Maple strips in a 4" PVC tube of water to soak for a week to try that method. It's in the sun for most of the day, maybe that will improve the soaking. I'll put some disinfectant or something in with it. While I had a tube full of water and some uniform strips of Doug Maple I thought I would check it's SG. 3' strips floated with 1" sticking out so they have a .66 sg.
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Thank you for joining in. I was thinking that no one was reading this. I wondered about laminating after my first try at bending a piece of Hazel as a test. I got quite a bit of spring back. I hadn't soaked it for a week or dried it for a week but still. It would save me building a trough to boil it in. It would also save me a month in drying. Did you use epoxy or hide glue?
You kidding me! I love watching the horn bow build alongs! I think your doin great!
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Thanks DH :D I found a way to dry the siyah lams faster.
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5 piece construction....
Laminated siyahs are over 25cm in length - entire kasan and tip ...
I have found some pictures from project -
1. pictere of the form and
2. gluing siyahs into limbs ..
Oh, when you say you are gluing up the siyahs with 4mm lams how much of the bow are you making? Will your siyahs include the tips and the entire kasan or will it just be the tip and the outer half of the kasan. Put another way will you have a slice in the middle of the kasan? Sorry for all the questions. :D
Nevermind I just found it in Adams book on a 5 piece the splice is in the kasan.
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Thanks for the pictures. In the second picture would the kasan eye be just off the bottom right hand corner?
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Yes ...
Thanks for the pictures. In the second picture would the kasan eye be just off the bottom right hand corner?
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laminated siyahs for mongol bow - also from black locust strps ... this time glued with epoxy
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Mine are glued up(epoxy), we'll see tomorrow.
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I've mean meaning to make one of these for a long time. Finally got to it today. I need it to boil the limbs for bending. 37"x 6 1/2"x 3 1/2". Only one seam leaked and I got it fixed first try ;D ;D. It fits nicely across the stove. With an inch or so of water in it there was a 10°f difference in water temp in between the burners. Hopefully with more water in it that will even out. I'll try it in the gas barbecue and see if that works.
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Might try a campfire with that and put the coals around it. Be carful not to melt itvthough
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It's galvanised steel, it won't melt. The corner solder joints are the weak point but as long as its full of water it should be fine.
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The test laths have been soaking for 4 days so I'm giving it a try. I'm going to boil them for an hour and see what happens. I have backing strips clamped on and I'm boiling everything together. It's 30" from the kitchen stove to the shop and the door is open. I've got the caul all set up with clamps open and wedges ready. We'll see if I forgot anything in an hour :D
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It went better than I expected. the test laths had a couple of small knot and I expected trouble from them. But everything is bent and clamped up and looks good. can't see any splinters. First one took less than 2 min from out of the hot water and all clamped up. I had trouble with one clamp so the second one took 2 1/2 min. I can see where the caul needs a little mod. More on that later. So now they have to dry on the caul for a week. That will give the real laths time to soak.
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Caul mods. You can see just to the right of the two sharp bends that the wood didn't go right down tight to the caul. I'm thinking that's because the clamp is too close to the bend. If I cut on the black lines, next time I'll be able to move the clamp to a better position. I may have to beef up that area.
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Good on you for attempting a hornbow :) A 100 mile journey starts with a single step....
A bit of advice - you need to make the kasan eye bend less severe/greater radius and your tip bend could do with being tighter. A way to concentrate the tip bend and make sure it is exactly where you want it is to rasp out two curved 'scallops' from the inside of the lathe, one on either side right where you want the tip bend to be. This method means that there is less wood to resist the compression during bending which equals less chance of raising a splinter on the outside of the bend.
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That was mentioned in Adam's book. What do you do with the "scallop" when you are shaping the back or do you leave the lath thick enough so that the bottom of the scallop is the finished thickness?
Also I got the impression that the radius of the kasan eye varied from war bow to flight bow. As no particular radius was mentioned I just assumed it was an individual choice. I will work on that after I take these trial laths off. A little heat should straighten them some. In order to end up with enough total reflex should I increase the amout of sal bend wgen I decrease the kasan eye bend?
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I make my lathes 40mm wide give or take. The scallops are around 25mm long and go into the width of the lathe by around 10mm each side. This leaves around 20mm width to play with when trying to get a straight core. The tip is only around 10mm wide when finished. This centre section is of course left full thickness, ideally 18mm. They are around half of the thickness.
If these cores you have already bent have knots in the them no matter how small they are no good for making a bow.
It is a while since I have rad the section in Adam's book on core shape but I seem to remember he does mention a radius as a starting point. It is easy on the first few bows to end up with a stiff kasan eye that doesn't flex quite enough. Also if the kasan eye is a tighter radius the bow will be quite a bit harder to stabilise and the sals will have a lot more stress on them so it is best to start a little 'relaxed'.
The difference between a flight and war bow is more how the limb tapers and thus where it bends. A war bows thinnest point will be right at the kasan eye causing quite a lot of bending there whereas the flight bows bend closer to the handle. Without getting too deep into the whys and wherefores the warbow is less stressed and able to be kept strung for long periods with little deteriation of performance due to the bend being spread over a longer bending limb. The flight bow however has quicker return speed of the limbs as the bend is predominately closer to the handle.
The sal should be straight and gradually blend into the kasan eye, the kasan is again straight (important) with the tighter tip bend aided by the scallops. Don't worry too much about totally reflex to begin with, as long as the tips are more or less 90 degs to the handle/sal section it will be good.
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Oh, the scallops are on the sides, I missed that, that makes sense. Thank you. My laths are about 35mm so I'll have to go lightly. The laths I have bent are just for testing methods and such. I will work them up to the point of getting ready to glue on the horn and then I will trash them. They have quite a few knots. They would have made a nice selfbow though. :D I also thought that if I could bend the ones with knots then the good ones should be a cake walk.
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Here is my form by itself. If I round off the eye bend that will shorten or straighten the kasan. The Book says I should keep the kasan straight if I'm reading it right. Should I start from scratch.
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I've taken the test limbs off the form and there was a fair bit of springback. I glued a piece on the sal end of the eye and rounded off the eye a bit. You can see the kasan eye bend is not so tight. Hope that's enough. I may make the tip bend a little sharper. I set it at 150° like The Book say but I may go to 140° to account for springback. It's also a lot easier to pull bend out than put more in. I didn't see any mention of springback in The Book. Maybe the longer soaking and drying would help. I should have waited but at least I'm working on something. I'm squaring up one of the test limbs pretending this is the real thing. I'll splice a scrap handle on it and see what happens.
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I managed to get registered to the ATARN forum but there's only one or two people on there. Maybe more will show up.
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My test limb and practice grip to sal "V"joint. I've never used hide glue for a joint, should the joint be a loose close fit or does it matter if you have to tap it home?
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The main criteria for the fit of the joint is that there is no light showing through once they are fitted together. It doesn't matter if the joint needs to be tapped home better that than too loose. The hide glue is perfect for gluing splices. Sizing parts well (with heat), apply thicker glue and push together. Let the glue gel properly. Then clamp lightly. I've done them with no clamps when the splices are perfect with no problems. Make sure and apply a fillet of extra glue once clamped.
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-close fit as possible
-make the joint area rough with saw blade (longitudial moves with saw blade for metal - small teeth)
-the joint area should be sized well with thin (hot) hide glue - at least 5 times. Let the thin glue penetrate wood properly and dry after each layer .... 10-15 minutes (gently heat with heat gun)
-Then make the glue thicker and put one thick layer of glue
-put the clamps on and tight well
My test limb and practice grip to sal "V"joint. I've never used hide glue for a joint, should the joint be a loose close fit or does it matter if you have to tap it home?
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I'm curious about something. You put on 5 or so coats of thin glue letting it dry between coats. Are you then depending on the thick wet coat to reactivate the dry coats? It just seems like a bit of redundancy. Why not put on a sizing coat and let it gel then immediately put on the thick wet coat. Wouldn't that accomplish the same thing without the waiting and maybe even better because you don't have to hope that all five layers get reactivated. I know this is the way it's done, I'm just wondering why.
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Here's the test bow glued up. I'm going to modify the form to put more angle in the tip kasan bend. I may try to put a little more bend it these with dry heat just to kill a little more time :)
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The reasoning behind letting the coats dry is so you cannot get a dry spot in the joint.
Applying glue, letting it gel then applying fresh glue would mean that the first just gelled layer could be removed (or part of it) when fitting the parts together. The dried layers of glue cannot 'come off'. All the layers do not need to be reactivated just the surface. This method of sizing with many coats of thin glue, drying inbetween and then applying the thicker final layer works perfectly.
Collagen glues contract as they dry and therefore wood to wood joints do not need high clamping pressure in fact it is counter productive. The key is close fitting, smooth surfaces to start with. Roughened surfaces trap air bubbles reducing glue saturation of the surface.
I like to test all these things for myself and it doesn't take long to glue up some test pieces. Try scraped smooth surfaces, 60 grit roughened surfaces, no sizing, thin glue, thick glue, clamps no clamps etc and then break them all. All in the name of experimentation and a bit of fun :)
It is well worth experimenting with the horn to core joint before going for the actual glue-up.
Yes you want to increase that angle in the tip bend or else the bow will stack early and not store as much energy as it could.
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I just noticed something(I can be a bit slow at times). With self or backed bows I avoid putting a splice in a bending area of the limb. The grip/sal splice extends well into the bending limb. Is this not an issue when the splice is sandwiched between the sinew and horn?
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Here it is at the end of today. Dry heat wouldn't cut it so I steamed the tip/sal bend to look much like I hope it will. There is a little reflex bend just at the end of the sal/grip splice on the left side. I'll have to watch for that kind of thing on the real one. No twist in this one. the centerline is nice and straight. Does this look more like what I should be trying for?
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It looks like it’s coming along
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No the location of the splice doesn't matter as it is in the core. The sinew does all the tension work - if not the bow would blow before even getting to brace height :)
Yes the tips look better now but as you say be careful about not having any bend in the sal area.
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Should there not be any bend(reflex) in the sal? Does that all come from the sinew shrinking? Should I modify my caul some more?
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Sinew shrinking doesn't give the bow much reflex at all. Most of the gained reflex comes from tying the string between the tips and increasing the reflex after each layer.
The sal should be straight to begin with.
Adam explains the reasoning behind not having reflex in the sal it is to do with separational forces between the layers.
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I sure seem to miss a lot in that book. Today is bend the real limbs day. I'll leave the sals straight.
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OK the real limbs are bent. It went very well I think, can't see any cracks. Time will tell. Now I have to wait a week. Not good at that ;D
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Perfect :)
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Thanks ;D ;D
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How do you know where the apex of the kasan bend/eye is? I've looked through Adam's book and I can't find it. In the two bows he gives the measurements for he says where the kasan/tip bend is but nothing for the kasan eye.
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You establish your thickness taper so that the thinnest point is maybe 5 cm before (sal side) the apex. The apex is the middle/ highest spot of the curve :)
Take a photo of your core lathes, mark where you think it should be and I'll tell you if you are right :)
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So the apex of the sal/kasan bend is decided by the thickness taper(tiller?) more than where you bend the lath? So is the kasan/sal bend more of a hinge than anything else? I'll take some pictures and mark my ideas on it after I moving and have my coffee. Thanks
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OK here is a picture of the limb. From A-B is 10.5cm(4+"), from B-C is 19cm(7.5")and C-D is 45cm(17.75"). So point C is the one I'm confused about. I arbitrarily put it at the apex of the bend I put in the form. Doesn't that become the kasan eye or can I move it some by varying the thickness? Is there some size/length relationship between the tip, kasan and sal? I found a picture in the book(in the Ottoman Bows design section) that says the tip can be 6.5-12.5 cm long and the kasan can be 11-21cm and there is no dimensions given for the sal. This doesn't help at all. Everyone swears by this book and I just find myself swearing at it. He seems to leave out one or two dimensions in every discussion. Sorry, I'm just getting very frustrated with this whole thing. It's a good thing I have to wait for these limbs to dry. It will give me some time to try and figure this out.
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If you have total length and this length is divided into three sections, two of the dimensions are known therefore the third length is...........what you have left :)
It all makes sense once you have made a few :)
There is no set measurements for the parts, there is a fluid relationship between them depending on what you want the bow to do. Look at the table with all the old bow dimensions on so see how things vary.
No the kasan eye isn't a hinge.....it is simply the apex of the bend and 5cm or so before it is the thinnest part of the limb. You have marked the correct spot on your picture.
When you make your first bow you are still seeing everything with a beginners eyes, remember your first wooden bow? It may sort of make sense but as you gain experience you start to appreciate how all these factors come together to form the whole. You will also see that Adam hasn't missed anything out ;)
Patience grasshopper ;)
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Wow. That is bow building at it"s best. I would love to see that bow finished and shooting. Excellent build along.
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Thanks Bassman. I'm still in waiting mode so I thought I would try my hand at making a groove scraper. I used an old cabinet scraper for steel. I had a bit of a chore getting it soft enough to file and then it warped when I hardened it but the screws pull it down flat. It's 16 TPI. I'm having a tough time seeing the teeth to get them even. Maybe I'll go buy a pair of reading glasses. I was using a magnifying glass but trying to file one handed ain't my thing. I didn't notice how uneven the teeth were until I took the picture :-[ :-[. I still have to make the alignment tooth. I'll post a picture of it then. I'll have to play orthodontist with those teeth first though. I did a test scrape and even with the crooked teeth two pieces mesh quite well.
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And with the alignment tooth and some sample grooves. Groovy ;D ;D
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Hello DC,
You can make pretty good scraper from saw blade... buy some blade like this in the picture and file only VERTICAL side of each tooth ! You make 45 degree from this 90 degree slope in just two moves !
Do not touch the other side ! :) .... to not mess with symetry
Count the moves, one ore two moves more and symetry is gone :-[
Here is my scraper made from butcher saw 8)
Thanks Bassman. I'm still in waiting mode so I thought I would try my hand at making a groove scraper. I used an old cabinet scraper for steel. I had a bit of a chore getting it soft enough to file and then it warped when I hardened it but the screws pull it down flat. It's 16 TPI. I'm having a tough time seeing the teeth to get them even. Maybe I'll go buy a pair of reading glasses. I was using a magnifying glass but trying to file one handed ain't my thing. I didn't notice how uneven the teeth were until I took the picture :-[ :-[. I still have to make the alignment tooth. I'll post a picture of it then. I'll have to play orthodontist with those teeth first though. I did a test scrape and even with the crooked teeth two pieces mesh quite well.
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I may try that. I've got a bunch of old saws. I'll have to look and see how many TPI they are. The 16 TPI kinda looks small. Did you use the movable alignment tooth idea of Adam's?
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No,
I fixed the bow perpendicular on the desk ..the desk was the guideline for scoring blade.
I may try that. I've got a bunch of old saws. I'll have to look and see how many TPI they are. The 16 TPI kinda looks small. Did you use the movable alignment tooth idea of Adam's?
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Remember the old bows weren't made with matching grooves. It is a nice thing to do but unnecessary. The more bows I've made the more I think it is a waste of time making matching grooves. My heaviest, most stressed flight bows have non matching grooves. One of them has survived two broken strings in the name of testing with no problems. With non matching grooves you don't have to bother making the teeth even in fact it is best if they aren't even.
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I've read that and I may not do it on the next one(if there is a next one). I thought that it might be a little insurance on the first one and it's part of the whole experience I guess.
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I tried grooving a piece of wood similar size to the horn. I couldn't get the alignment tooth to keep in the groove. It kept following the grain. I finally gave up and made a trough. That seems to work better. The scraper I made from a cabinet scraper was too thin. At least that's what I think was causing a horrendous squeal that would feed back through my hearing aids and get worse. If I took the aids off I couldn't hear anything and I'm not sure which was worse. I'm just about done making one from a saw blade. It's a little coarser at 11 TPI.
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Practise :)
It is easy enough once you get the hang of it. More tpi is better. Less tpi means you've got to groove deeper. If it was following the grain make the initial straight groove deeper. Use a scapel or very thin blade.
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Remember the old bows weren't made with matching grooves. It is a nice thing to do but unnecessary. The more bows I've made the more I think it is a waste of time making matching grooves. My heaviest, most stressed flight bows have non matching grooves. One of them has survived two broken strings in the name of testing with no problems. With non matching grooves you don't have to bother making the teeth even in fact it is best if they aren't even.
How heavy are your bows? Not many people make these with non matching grooves, so i'm really interested. Some people leave non matching groove bows lighter, cause they still fear the glueline. I feel there is some vital info still missing from the old way to gluing up core and horn.
My last couple of bows, i've used toothing plane blade. It's really a pleasure to groove with, it's high quality tempered steel and easy to sharpen with. I think you can find a picture of it from my hornbow thread here.
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Sinew shrinking doesn't give the bow much reflex at all. Most of the gained reflex comes from tying the string between the tips and increasing the reflex after each layer.
The sal should be straight to begin with.
Adam explains the reasoning behind not having reflex in the sal it is to do with separational forces between the layers.
You can have reflexed sal sections, as many many bows back in the day had. Separational forces are real, bigger with thicker limbs, but doable with good glue up work.
Crab bows, korean bows, tatars and turkish flight bows area all believed to have almost tip crossing reflex before sinewing.
Sinew reflex is nice, but what really makes the form is the wood core and horn. If sal sections are straight before sinew, eventually the bow will also be straight in these sections after tillering. All these bow types i earlier listed, had quite generous reflex when off the string. Well, my bows either haven't been reflexed this much, but in the future they hopefully will be.
That said, for a beginner or for a really heavy 150+ pound bow its good idea to have the bow less reflexed. It raises the possibility for a successfull bow greatly.
Good luck!
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This bow will be 40-45# so I'm not expecting it to be a screamer. If it's any more than that it will be a wall hanger cause that's all I can pull. I'm doing this for the fun of it, just to see if I can.
At 40+# I probably don't need grooves at all but what the hey.
All my old saws had coarse teeth. 16TPI looked a little small to me but this 11TPI look too big. I'll look around.
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The grooves stop the core from breaking. Look into how modern composite materials work - same principle.
Yes I know you can have reflexed sals, I've done it quite a few times. I have made a few different styles not just Turkish. With perfect gluing technique yes you can get away with it but take a closer look at those designs you mention - straight sals all feature :) A reflex out of the grip is not a reflexed sal :) As you say tip crossing reflex before tillering means little it is the shape of the core that matters. Only Turkish flight bows (out of those that you mention) had slightly reflexed sals before sinew.
I am just tillering two new heavy bows, one flight and one war. I haven't weighted them yet but I've had to make a press for these two, I can't bend them to brace by hand....they must be close to 150# as I've tillered a few 80/90/100# ers. The bow I mentioned before has shot over 600 yards (with less than perfect arrows) my goal is get close to the old record of 900 yards but these things take time!
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I couldn't get the alignment tooth to work so I went with the trough kind of idea. I scraped one limb of the test bow and made a pseudo "horn" piece out of a piece of Ocean Spray. It has the same density as horn(1.2) so I thought it was a reasonable substitute. After steaming the "horn" they fit together nicely. Here's pictures of the resulting grooves and the scrapers and jigs. I used the bending form as one of the jigs. I just made one scraper blade and move it from handle to handle as needed.
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Yes I know you can have reflexed sals, I've done it quite a few times. I have made a few different styles not just Turkish. With perfect gluing technique yes you can get away with it but take a closer look at those designs you mention - straight sals all feature :) A reflex out of the grip is not a reflexed sal :) As you say tip crossing reflex before tillering means little it is the shape of the core that matters. Only Turkish flight bows (out of those that you mention) had slightly reflexed sals before sinew.
I am just tillering two new heavy bows, one flight and one war. I haven't weighted them yet but I've had to make a press for these two, I can't bend them to brace by hand....they must be close to 150# as I've tillered a few 80/90/100# ers. The bow I mentioned before has shot over 600 yards (with less than perfect arrows) my goal is get close to the old record of 900 yards but these things take time!
Well we need to disagree then about the sal reflex. All those bows had a huge amount of reflex, something that many modern era replicas lack.
Over 600 yards of distance would be a world record. How did you measure the distance?
It sure is true hornbows take all the time in the world to master. And then the shooting...
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Look again - no they don't have hugely reflexed sals. When the core was made and the horn glued, they are straight in the sals. As I said I've made a few bows of all the designs you mention.
I don't really care about modern 'records'. I measured it with a 100 yard tape. The heaviest bows I shoot with a machine. Upto 80# I shoot by hand and have managed just shy of 500 yards with that bow but as I say arrows haven't matched the bows perfectly.
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Waiting for the laths to dry. This part sucks. :D
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Yup.....:)
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OK back to it. That's long enough. Lathes on the form. Lathes off the form. Sanding the lumps off the workbench so it's nice and true and marking the centreline on the lathes. I had to spend some time getting them nice even width and straight so they didn't rock back and forth on the workbench. I need a straight centreline so I can saw the "V" accurately.
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The handle section is Ocean Spray. It was nice having the lathes way to long so I could use both handle section points on the centerline. Trial fit and an idea of what it may look like. Not glued yet. I can't get used to the short working length of the limb. Right around 8". Crazy.
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And here it is glued. 5 or 6 sizing coats of 10% and glued with 30%. Boy, I'm having trouble trusting this hide glue. I've glued a few things and they've stayed together but it's sure tempting to use epoxy :D
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Collagen glue is the only sensible way to go. Don't use epoxy you will be glad you didn't later.
The sals look short and the kasans too long. On your first it is best to go with a less stressed design as Adam mentions.
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I thought the sal looked short but I couldn't find any measurements anywhere. I thought I was roughly following the two examples Adam gave(the 47" and 41" examples) but I guess not. This whole build is starting to pi$$ me off. maybe I'll just make shoehorns out of the horn.
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Last couple of days have not gone well. I've been trying to cut matching grooves in the horn and core. Even if you make a form for the grooving tool to follow the teeth follow the grain of the wood and the grooves don't end up straight. It's easier to groove the horn as it's grainless but still, all that has to happen is for the tool to jump a groove once and then from then on that's where the tool goes. Seems rather strange that the tool would rather follow a crooked line than a straight one but that seems to be the rule. Same thing happens on the wood. Fortunately Adam says that with a light bow you don't need matching grooves so I will forge on with sorta matching grooves and sals that are too short.
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Be interesting to see how you tiller such a beast and brace it. Hopefully it turns out well.
my last one piece bow broke.. :( so I decided to make 2 sets of limbs for a takedown, that way I know at least one pair of limbs wont break. That bow had perfect cast, smoothness and draw. After 9 years of doing this it was the best.
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I had a little talk with myself. I'm better now I think. I watched some of JWB's videos on grooving and he does it exactly as I was so I gave it some thought. All I could come up with was my scraper may not be sharp enough. I resharpened it as best as I could paying particular attention to face where the burrs are from filing. I ran it over a stone to get it nice and smooth. That seemed to help quite a bit. It's now sharp enough to cut new grooves rather than just follow what's there. I managed to straighten out some wiggles on the horn.
I decided that the sal/kasan bend could be a little less abrupt so I heated it while stretching out the bow. It looks a little better now. After it cools I'll try the sharpened groove cutter on the wood. If worse comes to worse I have enough to sand the old grooves off and cut new ones.
I also made up this little tool. I just bent the tang on the same size file I used to cut the teeth in the grooving tool. The file lays in the partly cut grooves and I can straighten out slight wiggles.
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Be interesting to see how you tiller such a beast and brace it. Hopefully it turns out well.
my last one piece bow broke.. :( so I decided to make 2 sets of limbs for a takedown, that way I know at least one pair of limbs wont break. That bow had perfect cast, smoothness and draw. After 9 years of doing this it was the best.
This is the toughest bowyering project I've taken on. It's brought me to my knees a couple of times so far. Bracing and tillering scares me but I'm not there yet by a long shot. I'll cross that bridge if or when i get to it :D
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DC you got this ,know you have the skill and desire so hang in man and i for one bet you build a fine bow .
i just got out of the hospital again and i guess i bought a little more time ,BUT i sure want to see it together and you standing in the yard at full draw. :BB :BB :BB
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Thanks ohma2 I'll rush as much as I can but a lot is just waiting for stuff to dry. You hang in there :D
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Groovey ;D ;D I'm happier with this. I managed to correct the horn but I had to sand off the core and start again. It went straightforward this time. Now I can start sizing.
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OK the first horn strip is glued up. My gut says the glue was a little thin but it's the 35-40% "the book" says. It was dribbling all over. I used clamps instead of the rope. I figured speed was the thing, gitter done before it gels.
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how many strips of glue will you be gluing on?
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If you mean horn, one on each limb. The horn forms the belly.
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That horn may stay stuck but you really should make the pressure strip that Adam shows. You only need a strip of material and some scraps of pine. You also need a clamp every 2 inches max.
When the horn is heated correctly just prior to gluing eg. 45 - 50 deg Celsius it becomes too soft to be clamped correctly when using just a clamp. You have a lot of pressure in one spot and little (because the horn is soft) between the clamps. That is the reason they used the rope method in the past. Perfect pressure everywhere, it is also very quick when you are practised at it. Even clamping pressure is very important.
The good news is that partial delams are fixable but of course they are best avoided in the first place.
I wouldn't use a greater concentration than 30% glue.
The way to get the grooves perfect is to use a scalpel for the initial straight cut. Then a slightly thicker blade. Then use a very sharp scraper with a narrow projecting foot. Once you have done a couple it is pretty easy. The other methods are ok but not as good as the method Adam describes. The 'best' modern way is to get a router cutter made with 2mm equilateral triangles, make a sled for your horn and one for the core...... = perfection :) but not exactly traditional!
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The clamps are spaced right. At least I got something right. I'll make up a pressure strip for the next one.Is your 30% glue quite runny? I watched a bunch of videos and their glue always looked thicker than mine but it's pretty hard to see. I tried the method of grooving with the little guide tooth and it didn't work for me. Possibly it was because my grooving tool wasn't sharp enough. I never had any trouble with grooving the horn or the really dense wood that I practised on but as soon as I tried to do the Maple it would climb out of the grooves. Once it's crossed over it's really hard to get them straight again. I found that just knocking the points off with a stone so that each tooth ended in a sort of chisel shape(very small) it helped a lot. Now that I have the cutter working better I'll go back and try the guide tooth thing again. It seemed like a lot more user friendly method than the guide rail. Have you had a router cutter made? Was it expensive? Thanks for the input. Much appreciated.
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Oh, when I was sizing the horn and core using 10% glue little bit of fiber or whatever would make small lumps and nibs in the sized surface. I dusted thoroughly before sizing and cleaned it with a small wire brush. Do these normally soften and squash down when you glue? I took a quick, very light pass with the groove cutter just to clean them up before I glued. Just wondering if it was necessary.
PS I found a place that custom makes router bits I'll contact them tomorrow.
PPS How long should I leave this clamped up?
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Oh, when I was sizing the horn and core using 10% glue little bit of fiber or whatever would make small lumps and nibs in the sized surface. I dusted thoroughly before sizing and cleaned it with a small wire brush. Do these normally soften and squash down when you glue? I took a quick, very light pass with the groove cutter just to clean them up before I glued. Just wondering if it was necessary.
I did the same to clean the grooves ...
I used heat gun (gently) to speed up the drying of the sizing coats....
PS I found a place that custom makes router bits I'll contact them tomorrow.
PPS How long should I leave this clamped up?
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Thanks for the post gorazd. :D
Here's a pic of my clamping belt. 2"x 1 1/2" plywood glued to seatbelt material with Shoe Goo. Handy stuff :)
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The clamps are spaced right. At least I got something right. I'll make up a pressure strip for the next one.Is your 30% glue quite runny? I watched a bunch of videos and their glue always looked thicker than mine but it's pretty hard to see. I tried the method of grooving with the little guide tooth and it didn't work for me. Possibly it was because my grooving tool wasn't sharp enough. I never had any trouble with grooving the horn or the really dense wood that I practised on but as soon as I tried to do the Maple it would climb out of the grooves. Once it's crossed over it's really hard to get them straight again. I found that just knocking the points off with a stone so that each tooth ended in a sort of chisel shape(very small) it helped a lot. Now that I have the cutter working better I'll go back and try the guide tooth thing again. It seemed like a lot more user friendly method than the guide rail. Have you had a router cutter made? Was it expensive? Thanks for the input. Much appreciated.
If you make the glue thicker you will have less time before it gels. The sizing coats eliminate the chance of there not being 'enough' glue in there once it is dry.
The way to know for sure with your glue is to start with dried, hard glue. Weigh the amount you intend to use. Say you have 30 grams of glue add 70 grams of water to make up a 30% glue.
Yes you can use a new, sharp triangular file to straighten any wiggles. As vyou say a very sharp scraper is key, that combined with a narrow footing and the scalpel, followed by a slightly wider blade for cutting the groove on core.
No I didn't bother getting a cutter made but have seen it done and know from doing a lot of router work that is would be quite easy to get them absolutely perfectly straight and matching. You just need to make the right sleds to hold horn and core. The fact that it would take about 5 mins once you have the sleds made is quite attractive but not exactly traditional! However at the end of it all matching grooves aren't even necessary! If you use two slightly different scrapers one for the horn one for the core the job doesn't take so long and there is little chance of messing anything up.
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Oh, when I was sizing the horn and core using 10% glue little bit of fiber or whatever would make small lumps and nibs in the sized surface. I dusted thoroughly before sizing and cleaned it with a small wire brush. Do these normally soften and squash down when you glue? I took a quick, very light pass with the groove cutter just to clean them up before I glued. Just wondering if it was necessary.
PS I found a place that custom makes router bits I'll contact them tomorrow.
PPS How long should I leave this clamped up?
Ideally it should be a perfect even layer everywhere and glossy. If the sizing isn't right it is usually best to wash it off and start again. I like to use very thin glue (5% max) and about 20 -25 coats is usually sufficient. The thinner glue wets the dense surface of the horn better. and naturally dries a bit quicker. The sizing coats shouldn't be dried warm just use patience! It's better to be patient now than have a bow that delaminates later.
The 'bits' might be in the glue? Try straining it. The horn should have no loose bits on it at all. The last pass with the scraper should leave it shiny. Any areas that need a clean up can be sorted out with a scalpel blade with a triangular end used like a scraper.
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Pressure strip looks good :)
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Thanks for the posts bownarra. Filtering the glue is a good idea, it's probably gotten a little mungy. It went on real nice and glossy, it just had a few nibs. How long do you let it dry before you unclamp it? I need the clamps for the other side but I may buy some today.
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Thanks for the posts bownarra. Filtering the glue is a good idea, it's probably gotten a little mungy. It went on real nice and glossy, it just had a few nibs. How long do you let it dry before you unclamp it? I need the clamps for the other side but I may buy some today.
I used the rope and waited couple of days ... just to be sure (-P
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More questions. in the book Adam says to use very hot glue. Everything I've read says the optimum temperature for hide glue is 140°f. Is that what he means by very hot?
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Yes that is correct. It will start to degrade once you hit 65 - 70 Celsius. I judge the temperature with my fingers now I have the feel for it. A simple test without a thermomenter is to get a very fine piece of sinew and dip it in the glue. Too hot and it will shrivel up.
I also leave it a couple of days to be sure. I once had a strip with matching grooves misalign when clamping. The first clamps were only on long enough for it to gel.....you wouldn't believe how hard it was to get off even after that short a time. I would think that one day is plenty but....
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Thanks. One more thing cleared up :D
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Glued the second horn strip this morning. It was little more stressful than the first. The pressure strip added to my clumsiness and I got the grooves misaligned. The second time I did the first fit with a couple of clamps without the pressure strip to make sure the grooves hooked up. Then I clamped on the pressure strip on removing the first clamps as I went by. It started to gel as I was double checking all the clamps. Now it's wait for another month. Adam says I can fit the celik while it's drying. Can I do any other portion of the shaping?
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The trick is to wrap the horn onto the limb with thin, like a single strand of bowstring thin, cord. Use quick clamps initially to hold it in place, then wrap with the thin cord, remove quick clamps, fit proper clamps.
No its best to leave it for that long for the collagen bonds to form properly. I normally strip the sinew now. Go as fine as you dare and prepare 100 grammes.
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Thanks for the cord tip.
268 grams of elk leg sinew almost ready to go. Well, some of the 268 is bag.
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Now I wait another month ::) ::)
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ugh the anticipation almost killed me the last time! well ill work on my hackberry bow if we have to wait.
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And this is one of the easy waits. Something like 6 months to a year for the sinew to dry.
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Are you going to wait 6 months on the first bow though?? :)
You only need to leave it 2 months to be dry enough to tiller(if sinew is put on it thick layers). It probably isn't worth waiting that long on the first bow as it is likely to have 'issues'.
If you put your sinew on in 1mm thick layers 2 weeks drying time between layers is plenty. The very long drying times are only really for the sinew down the edges of the limbs. It can be 5mm thick there. Or for the very best performers once you have your methods totally down and you know nothing is going to go wrong during tillering.
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That's good news. Thanks
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The 'best' modern way is to get a router cutter made with 2mm equilateral triangles, make a sled for your horn and one for the core...... = perfection :) but not exactly traditional!
$275 to make one, too rich for my blood. ;D ;D
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OK back on my head. I can start shaping. I ground the excess horn off the edges so the bow will sit flat on a flat surface. I got a chip but it's where the horn will be tapering out to nothing. Horn can be brittle if you hit it the wrong way with a rasp. Then I figured where the centreline will be, double checked it and marked it all around with a compass. I couldn't see the pencil line so I covered the horn with masking tape and remarked it. I was pleased when the centreline was in the same spot ;D ;D. Then I laid out the width according to the measurements in "The Book". It looks very narrow.
Question for Bownarra In The Book he suggests making the kasan 2-3 mm wider for stability. Why just the kasan, wouldn't making the whole limb wider help the stability even more? It would mean making the limb thinner to maintain the DW I guess but isn't that doable?
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More
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YES!! were back!
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I like the compass method :)
You could increase the width of the sal as well but it isn't really necessary as the extra stability is needed around the kasan eye. As it is the place with a bunch of reflex it is the 'problem area'. Remember the 100# plus bows aren't wider than around 30 - 33mm in the sal. Increasing width and decreasing thickness in the sal will also affect the return speed of the limbs. I presume you are making a lower weight bow? I just finished tillering a bow that is around 40#@28 and it is thin! The thinner these bows become in the sal the more finicky they can be.
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So instead off tapering as much in the sal I should keep the width further into the eye a bit and then have more taper in the kasan. I'll do that for now. I can always taper more. Yeah, I'm planning on about 45#@28. That's about all I can pull.
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Yes but keep the extra width for the full length of the kasan go back to standard width at the 'step' into the tip. I would aim for about 24 mm width at the end of the kasan and then reduce width to 11mm, thickness 17mm at the tip.
You can then reduce width of the kasan once the bow is tillered and stable.
One thing that is easy to get wrong is leaving the core too thick at the kasan eye. You want it to open almost fully here at full draw but if you leave the wood even a shade too thick it won't open much during the draw, this will increase set in the sals a lot and more importantly make stability more problematic than it needs to be.
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Step?
I got a bit of shaping done today. Narrowed and thinned. I don't want to thin the sals until I've finished the kasans and tips so I've got something to hang on to in the vice. The horn is about 4mm thick, I hope that's right. The Book is kind of vague about how thick the various parts should be. It's hard to shape a bow like this when you've never seen one. Pictures just don't work that well if you only have a couple of views. I spent most of the day searching the net looking for pictures of the kasan, eye and tips. Are Groziers bows fairly good copies, most of the web pics are from his site?
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Bit of a setback today. I was reducing the width of the tips. I had about 3/8" of wood to take off i couldn't reach it with the bandsaw because of the awkward shape so I thought I would use a hand saw. I got about an inch into the cut and realised that a rasp would be the better tool. I started rasping looking for the saw kerf to know when to stop. Never saw it go by :-[ :-[ :-[. So I epoxied a piece on to repair it. Once it's all shaped the piece will only be about 1/16" or less thick so I'm sure it won't be a problem.
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I was looking at my trial core wondering if I can use it for a bow. It is flawless except for this knot. If I made the limb 24mm wide it would go right through the centre of the knot on the belly. Where it appeared on the back would depend on how much core I used. If I made it 22mm wide it would almost disappear except for a wiggle in the grain. The core is the same shape as the one I'm working on so a little heat would straighten out the kasan eye bend. You can see where it is by the handle "V" joint. What do you think? If this was any other bow I wouldn't think twice or even once about it. :D
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Is this very roughly the shape I'm looking for at the tip/kasan bend? This is on the trial form.
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The knot makes it completely unuseable. Don't kid yourself into thinking it will work - it won't! It isn't just the knot it is the swirly grain that accompanies it that is also a complete no-no! This is the wooden bow making experience talking! Go back to beginner status and just follow what the book says word for word ;) You need a different mindset making hornbows. Literally every single thing must be perfect....or else that house of cards starts wobbling.
Your shape is sort of right but you do not want the grooves on the belly at the base of the tip. The tip should be triangular and the string simply sits on the side of the triangle.
Yes a step from the width of the kasan into the width of the tip. Don't blend/fade this area make it a step down in width.
I'll try and get a good picture of the tip.
No Grozers aren't really what I would copy.
You can get many pictures from the bows in the Topaki Palace collection.
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Thanks bownarra I wouldn't be this far along without your help, much appreciated :D
I tried a search for the Topkapi Palace collection but I'm not having any luck finding pictures of bows. Do you have a link that might get me there?
I'll continue using the knotty core for practice. So the kasan should be a sort of triangle with the point to the back and the tip should be a triangle with the point to the belly. JWB bows has a short video about carving this. He scoops the sides of the kasan. I read somewhere that this isn't necessary on a light bow. I would have thought that it would be preferable on a light bow to bring the tip weight down. What's your opinion on this?
Thanks again
Don
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Here is couple of pictures i took just couple of weeks ago. These are from Istanbul military museum, topkapi didn't have these angles to take pictures from. Actually its prohibited to film there but...
If you google "mandarinmansion turkish bow" you will find Peter Dekker's page that has a lot of close up pictures of good turkish bows.
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Thanks JNystrom I'll take a look.
I have more questions. This will be my last chance to get the horn to an even thickness. Is anyone willing to take a shot at horn and wood thickness for a 40-45# bow. the bow is 120 cm NTN, tip is 8 cm, kasan is 20 cm measured at the apex of the eye bend. Limbs are 24mm wide. At the moment the horn is about 4 mm thick. I think it should be closer to 3 mm but I don't know. I'm wondering if I shouldn't make the wood a bit on the thin side as I can reduce the horn on an assembled bow but I won't be able to get to the wood. The Book says the 3 parts should be about equal thickness which would put the sinew at 2 mm but The Book says I should go with 3 mm. Again, I can reduce the sinew if there is too much. Is it possible to reduce the draw weight on a completed bow? I'm concerned that this thing is going to be too heavy and be totally useless to me.
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Thanks JNystrom I'll take a look.
I have more questions. This will be my last chance to get the horn to an even thickness. Is anyone willing to take a shot at horn and wood thickness for a 40-45# bow. the bow is 120 cm NTN, tip is 8 cm, kasan is 20 cm measured at the apex of the eye bend. Limbs are 24mm wide. At the moment the horn is about 4 mm thick. I think it should be closer to 3 mm but I don't know. I'm wondering if I shouldn't make the wood a bit on the thin side as I can reduce the horn on an assembled bow but I won't be able to get to the wood. The Book says the 3 parts should be about equal thickness which would put the sinew at 2 mm but The Book says I should go with 3 mm. Again, I can reduce the sinew if there is too much. Is it possible to reduce the draw weight on a completed bow? I'm concerned that this thing is going to be too heavy and be totally useless to me.
The ONLY help I can offer is to take it off your hands if it comes in overweight. :)
I have always enjoyed your posts and craftsmanship, so I'm looking forward to seeing this progress to completion.
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so I'm looking forward to seeing this progress to completion.
So am I but boy it's tough at times. I've been close to packing it in at times just from the difficulty in finding out stuff. If it hadn't been for writing this build-a-long, I don't know. I've started reading so many of these things and have them fizzle out to nothing I vowed I would see this through make or break. I actually don't think the building is that tough, we'll see, but knowing what to do next is hard. The Book is supposed to have everything but it's buried. Once you figure out what to do all of a sudden it appears in The Book.
Sorry, Rant mode off. ;D ;D
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More practice on the trial core. I think I'm closer to the right shape. I must be getting close, the tip is starting to look very spindly.
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How do those not have torque problems?
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I think they do. Very great care is taken to have no twist or string alignment issues.
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Those dimensions that Adam gives in his book are just rough recommendations. If you use "too" thick horn, what are the worst things that could happen? The mass of the bow would be 20 grams too much, or little bit more unstable. As horn has less bend resistance than wood, there is really no fear of the bow coming overweight. With nice thickness horn of 4-5mm you have plenty of room for tillering and also the bow will hold reflex better.
Assuming the limbs are properly tapered and shape is nothing extreme, the sal thickness will tell you the final weight. 120cm #45 bow i would make the core about 8mm thickness in sal parts, 110cm #45 bow i would make 7mm. After this by giving the bow a plenty safe amount of sinew, 100g, would raise the thickness from 8mm -> 10mm and 7mm ->9mm.
These are just estimates, i haven't made a 45 pound bow yet.
I would throw that 1:1:1 rule to the dumbster. :D One reason is because the originals were done with 60 grams of sinew... There is a huge variation in the portions anyway, crab bows used couple of millimeters of horn, some turkish bows have even 8mm.
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i would make the core about 8mm thickness in sal parts,
Just the wood or is this wood+horn?
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Before sinewing, wood and horn only.
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OK that makes more sense. I was thinking you just meant wood only. Happy now ;D ;D
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More shaping today. I finally had to bite the bullet and settle on the thickness. It was a tough decision. With input from bownarra, JNystrom, The Book and a couple of threads from the German website "Fletchers Corner" (Thanks Simk)I was able to make a WAG and fly at it. The Readers Digest version is that the thinnest part in the eye will be/is 7.8mm and thickens toward the handle. I have no idea what draw weight I will get but it's looking like 40-45#. I'm in the process of joining the Fletchers Corner. I don't speak German so I'm getting Deepl(a translation program) and will run all my communication through that. There's at least a half dozen guys making horn bows there. As far as reading the forum the Windows translator works quite well and I've only had a couple of times in hours of reading where I've been stumped. I'm not sure how it will work with a two way conversation.
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Here's a picture with a tape. I took 6 pictures and this is the clearest(old shakey hands). Harsh criticism of every detail please :D I'm thinking it might be a little thick in the 5-15 cm range.
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I think you should thin down the sal area between 10cm point (from centre of the bow) and first nut..... and make the SAME thickness at least 15-20cm long to achieve nice bending of the limb.
And maybe thin down the area between first and second nut too...
I used the caliper ruler - and marked the points - and achieved 0,1mm accuracy when sanding the wood.
Sanding the wood:
I used the 100 grit sand paper on the small sanding block .... for best accuracy.
Of course .... before sinew job I roughed the wood with piece of old saw blade.
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Thanks gorazd The area around the first nut is around 8mm thick(3.5 horn and 4.5 wood) and 23mm wide. The handle is made from Ocean Spray, a very hard, dense, stiff wood and the end of the "V" joint is at the 16mm mark. My limbs are almost parallel, 24mm tapering to 23mm at the kasan/tip bend.
So should I be going down to 7mm from the second nut going back 15-20cm toward the handle or should I be down to 7mm at the 10cm point?
Sorry for all the questions, I don't want to mess up now and dump 4 months down the tube.
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Here is it :
"https://i.imgur.com/Tv4zuhF.png" - to make the bow bend more near the handle...
And ... I would recommend to thin down the section marked with red too - and make shorter kasan ....
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Great, thanks. I've been lurking on the German forum "Fletchers Corner" and I'm waiting to get accepted there. There is some mention of test bending before sinewing on there. Have you heard of that?
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Yes, I have heard about test bending before sinewing.
But I did not try ...
I used bamboo wood core and did test bending of the 5mm bamboo only - around the same bending raidus as future turkish bow - the bamboo survived, so I correctly exppected that 3mm core wood in composite would be no problem even I put sinew in thinner layers ...
Great, thanks. I've been lurking on the German forum "Fletchers Corner" and I'm waiting to get accepted there. There is some mention of test bending before sinewing on there. Have you heard of that?
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Time to start sorting sinew I guess. It's all shredded so it's just make piles and weigh out clumps. I'll save the final shaping for the last minute so I have fresh wood.
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Here are the measurements from my 40ish# bow. 121cm.
Center - 33mm
5cm - 26mm
10cm - 14mm
15cm - 10.4mm
20cm - 9.6mm
25cm - 9.1mm
30cm - 8.9mm
Kasan eye 35cm - 9.5mm
40cm - 12mm
45cm - 13.5mm
50cm - 14.5mm
Base of tip 52cm - 17mm
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It's a fast bow :)
I'll take some pictures this afternoon of it unbraced and braced. So you've got something to aim at.
As for bending just before sinewing yes you can do it and it is useful but you must bend the bow backwards, bending it the correct way any appreciable distance will of course break the core at one of the many grain violations ;)
Of course bending it backwards needs an eye for what the correct shape of a sinewed bow is when it is tied up for seasoning.....on this first bow just make absolutely certain you have a perfect taper with not even a hint of a thin spot anywhere and you won't be far wrong.
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Thanks bownarra, especially for the measurements. Something that's been puzzling me. Is it the total thickness of the limb that determines the DW(ignore length and width for this) or does the percentage of each layer have some effect. Would a bow that is 10mm thick have the same DW whether it was 1/3,1/3,1/3 or maybe 1/4,1/4,1/2. Within reason of course :). Adam suggests adding extra sinew on your first bow, isn't that going to increase the DW?
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Here are the measurements from my 40ish# bow. 121cm.
Center - 33mm
5cm - 26mm
10cm - 14mm
15cm - 10.4mm
20cm - 9.6mm
25cm - 9.1mm
30cm - 8.9mm
Kasan eye 35cm - 9.5mm
40cm - 12mm
45cm - 13.5mm
50cm - 14.5mm
Base of tip 52cm - 17mm
How much of that is sinew do you think? Rough width of limb? It's very similar to mine in general measurements but my eye is at 30ish.
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Today I'm organising my sinewing setup. Building a rack to hold the bow, calibrating my hotpot. Figuring out what length and how much sinew to put on the first coat. That kind of stuff. With any luck I'll do the final thickness sizing of the bow this afternoon and then maybe a couple of coats of glue sizing.
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Yes it is the total thickness that determines draw weight not how much there is of each layer. A bow with thicker horn will take a little less set therefore draw weight will be slightly higher but no it is the total thickness that matters.
When Adam mentions adding more sinew I think he means proportionately more sinew rather than adding 'extra' sinew. The 100 grams advise is what to go with here. 100g will probably mean you end up with 2.5 - 3mm sinew over the center of the sal.
I only used around 70g on this particular bow and horn of around 3mm in the main bending section. If I remember right these horns were recovered from an older failed bow hence the limited thickness.
This bow is around 32mm wide in the sal.
I would advise moving the thinnest section out to 35cm even if it is slightly around the bend. If your thinnest spot is at 30cm then the sal will be over strained. Better to have the thinnest spot even out to 37.5cm from the handle to lower the strain a little further.
One of the most important steps of the whole process is making sure the core is perfectly sized. Make sure you do not touch it with bare hands once it is prepared. A lot of hornbows fail because of broken cores where the sinew/wood bond isn't perfect (don't ask me how I know that one….haha).
Heat the whole core and use 5% glue for the first few coats. Very light sanding (240grit) inbetween if any fibers raise. Then you can increase the thickness of glue a little. Make sure it is glossy everywhere.
Good luck :)
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I would advise moving the thinnest section out to 35cm even if it is slightly around the bend. If your thinnest spot is at 30cm then the sal will be over strained. Better to have the thinnest spot even out to 37.5cm from the handle to lower the strain a little further.
Thanks for that, I was considering doing that so now I will.
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First coat of sizing on. I guess I'm on my way
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A question. Adam says to sinew within a day of sizing to avoid contamination. But then you can leave the first layer for a week or more before you put the second layer on. Am I missing something here?
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No not really :)
Just do as it says :)
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I forgot to say. when sinewing the sal I've found it useful if the first sinew you lay is on the edges of the limb. Like you are aiming to make the back flat with this first bit of sinew. Then when you add the further layers it is much easier to maintain the dead flat back.
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When your limb is only 6-7mm thick there is not much crown ;D I thought I was going to start to see grooves. But yes, I was going to build the edges on the first layer. That's going to happen any time now. I woke up this morning and it -4c (25f) out side. I've got 3 heaters going in the shop to warm it up. Glue pot is on , sinew is soaking and I'm nervous as hell ;D ;D
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I did the sinewing in korean style (seen in youtube).... to shorten the messy procedure and to be sure to put sinew more evenly on each limb. It is pretty fast too. More time was spent on sinew processing. I separated each sinew hair down to single one - using water (to get them soft).
I did it in 3 layers - 1 or 2 week waiting between each layer. One layer was around 1mm, all together 3mm.
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First layer done. Whew! I marked the thickness of the limb on the belly so I can figure out how much sinew I've applied. I started by soaking the sinew for a half hour or so. I had it all sorted in bundles ahead of time. Then I squeezed the water out and combed the bundles. I had four bundles for each limb. In hind site dividing it further may have been wise. It would have made for easier combing. After I had all the bundles combed out I sized the bow again with 10% hide glue. Then I soaked a bundle in the glue pot, squeezed the excess(judgement call) and smoothed it on to the bow. I did the same with both limbs and then came back and did the grip.
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More. Once I got sticking the sinew on my hands were too messy to take more pictures. So from the second picture on they are after pictures.
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More. The pictures make the sinew look lumpier. I put on about 60 grams of sinew. I wish I'd written it down because now I'm starting to get confused about what I did. I'm pretty sure I did 25 grams on each limb and 10 on the grip. I know I got it even but I'm just not sure how I got there. Stupid old fart. When it dries some the thickness will tell me.
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And here it is all gelled and reflexed some. The left limb is stiffer, darn. I just looked at the thickness measurements and where it's stiffer it's about .3 of a mm thicker. Thought I was close enough, should have done a test bend. Fussy thing. now i have a month off, maybe.
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are you able to fix that?
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I don't know whether I can do anything now, maybe someone will chime in. I think there is a little tillering I can do when it's dry. I just read a bit in Adam's book and it sounds like this is normal to have small imbalances once it's dry. Whether or not it should happen at this point is not mentioned.
I'm wondering if I should put a little pressure on the stiff limb now.
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Maybe as it's not reflexing as much, it will balance out when drawn. As the thinner limb comes around more just to make brace, the extra energy in the weaker limb may pull the stiffer limb back, continuing all the way to full draw until it's got a balanced full draw profile. I know I have read lots where heat is used to balance the limbs out on occasion as well. You may also get away with laying a little extra sinew on the weaker limb to strengthen it?
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Yeah, they use strange methods to arrive at final tiller so because of that I'm not sure how this would be solved. They use heat to adjust the kasan(the stiffer outer limb) but they use scraping, not heat, to adjust the working limb. Hope I've got that right.
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I didn't get the sinew nicely wrapped around the edge of the bow. How soon can I add more? Right away or do I have to wait until it's somewhat dry?
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It was getting worse as the sinew dried, I guess. So I modified the rack I sinewed it on to hold it a bit better. I don't know if I'm doing the right thing but I feel i have to do something. I might fiddle with it a bit more.
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It sucks, but it's not too late to pull the sinew off and redo it. The time it takes to build it right is small in comparison to the time you will enjoy a week crafted bow, even smaller compared to how long you will wish you had just redone it.
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You could wrap it in clear plas9to stop the drying process until you figure what to do.
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I think I'm alright. At least enough to not tear it apart. This one is just a learning experience although I have to keep telling myself that. It's not the first mistake. What amazed me is the thinness of the wood. There's hardly any in there.
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I would wait two weeks for sinew layer to dry then take measurement down to 0,1mm and sand the sinew layers - to equalise on both sides before starting with new layer.
Then next layer.
Try it korean style - put on layers in gelled state - then wet the layer and heat it with hair dryer - to get them in semi liquid state when they are on the bow already . You have more control how much sinew is added on each side.
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It looks a lot better this morning. I think clamping it to the frame let the sinew settle into the position I wanted rather than just any old place. We got hit with cold(ish) dry air from the interior so the shop, once it's heated, is 25-30%RH. It was 50°f and 35%RH in there this morning. I'll boil a kettle or two in there to moisten it up a bit but that doesn't last. It is what it is, I guess. It's freezing outside right now so I don't want to put it out there. The sinew is drying amazingly fast but I'll still wait a few weeks before I do the next layer.
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That's looking really great, DC!
Amazing how clamping it to the form like that has just convinced the sinew to do as it's told. It really is like a living backing.
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Maybe as it's not reflexing as much, it will balance out when drawn. As the thinner limb comes around more just to make brace, the extra energy in the weaker limb may pull the stiffer limb back, continuing all the way to full draw until it's got a balanced full draw profile. I know I have read lots where heat is used to balance the limbs out on occasion as well. You may also get away with laying a little extra sinew on the weaker limb to strengthen it?
No they need to be the same it won't balance out when you draw it.
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Don't bother trying to alter the shape now. Heat/tillering will take care of it later. It may actually be counter productive trying to force it into a different shape.
This is why it is worth bending the bow backwards before sinewing but don't stress it isn't bad. I've had worse and corrected it later.
Just because the sinew looks dry only means the surface is dry :) The bonds take time to form.
You should separate the sinew bundles further and weigh each bundle to 0.1g accuracy. My bundle weights vary between 0.5g and 2g. Slightly more sinew on one side of the limb will cause twist that is very difficult to cure later.
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It's pretty much settled into it's shape now. It doesn't move when I take it off the form so that's done whether it's good or bad. I will reverse tiller the next one. I was a little hesitant this time but now i have a better idea of what to look for. I realise the sinew isn't dry, I was just surprised how fast it went from gelled to "hard to press with a fingernail" stage. I weighed it right after sinewing and it was 372 grams. This morning it's 312.
You should separate the sinew bundles further and weigh each bundle to 0.1g accuracy. My bundle weights vary between 0.5g and 2g. Slightly more sinew on one side of the limb will cause twist that is very difficult to cure later.
I did weigh my bundles to .1g so I'm OK there. I wish I'd known about bundle weight being .5 to 2 gram. That would have been a big help. I think my bundles were 6.5.
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Yes I like to use small bundles to begin with and get the finished shape with them and then use the full width bundles for the last layers.
The bigger bundles are much easier to handle when you use the Korean method like Gorazd mentioned.
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Second layer of sinew today. Sorry no pictures. Pretty much the same as the first layer except I don't feel as good about this one. Not sure why. A gut thing. See how it looks in a day or so.
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I'm new to sinewing so I'm not sure what to expect. I'm surprised how crummy the sinew can look when you apply it and the next day it can look quite nice. That's the case with this layer. I'm quite happy with it this morning. The light spots on the pictures are still wet so it should get better still. The fourth picture is an older one to show how much reflex it's gained. It weighed 440grams right after sinewing and it's 404 this morning. I measured the thickness of the first layer before I put on this one and it was in the 2-3mm range so this one may be the last one. I would like to put on a thin smoothing layer after I sand/ rasp this one a bit. Brings up a question, how much sinew can you remove? I can imagine that rasping the layers cuts the sinew a shortens the fibers. Is this a problem? How much can I shape the sinew? I'm thinking I should level/even out the sinew before I start tillering so the thickness taper is OK. Kind of using the rasp to fix up my less than perfect sinewing.
PS Found the answer in Adams book. After 3 months I can shape the sinew.
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If you are close to using your allotted amount of sinew then make sure to reflex it more after the last layer is added. The tips should be close to touching. This also helps with stopping delamination between the sinew layers.
The trick with sinewing is to try and establish the shape you want after the first layer then you only have fine adjustments to make on subsequent layers.
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Thanks for posting this thread, I've been saving it up to read in one go, my build stopped when I could not get perfect core wood, changed jobs, life got hectic, blah, blah, blah. I have a copy of The Book and I have read it many times and still struggle with lots of information I need as a novice that is missing - the earlier explanation of glue percentages, for instance, finally answered a question I have been unable to get my head around since I first read The Book three or four years ago. Anyway, this thread is really inspirational and very, very useful, so many thanks.
Andrew
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Once you have read the book AND made a few bows you will realize that ALL the info you need (and more) is there. You may not realize it but it is there :)
Practical experience trumps all when it comes to learning the intricacies. You simply need to roll the sleeves up and have a go to start the real journey :)
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I agree that the information and more is there and find the book excellent in almost every way, I have unreservedly recommended it and even managed to print off a hard copy, but, it is not without its frustrations, and that is where threads like this come in, coming back to the glue issue, for instance, I mix glue from powder, so, 30% is a bit tricky to understand, is that by weight, by volume or by made and dried glue? Is made and dried glue always the same strength? So, when the solution (sorry couldn't resist that pun) pops up in a thread like this it just fills in the holes that the writer assumed we all know.
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When I made a 35% glue I used 35 grams of dried glue and 65 grams of water. I'm thinking that within 5-10% is close enough. As it's sitting in the pot the water is evaporating and then you add "a bit" of water to thin it out again I'm sure the concentration drifts around that much. Made and dried glue depends on your definition of the word "strength". If you mean "concentration" then dried glue is dried glue. When you make glue the first pour will be a stronger(physical strength) glue than subsequent pours.
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DC has got it :)
Dried glue is only glue :) Measuring is done by weight.
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So if I make gellatin glue from powder the weight of the powder is the same as if it were made up and dried out glue sheets
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Yes with a but. The weight of the "dry" glue will vary with RH so there will be a little difference. Not enough to worry about. You may be more anal than me ;D ;D. The only reason I mentioned it is that I went on a search for this and wound up on some luthiers sites. These guys define anal. I just didn't want to give you my opinion and have you find a luthiers site that made me look like a liar. ;D ;D ;D
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How long can I leave the sinew between layers? I've cut the tip of my index finger fairly badly carving a 1/4" long eagle for my grandsons model railroad. Adam says two weeks max between layers and then says in the curing section that if, after 3 months,if it's not thick enough to add another layer. I think there is enough sinew on it now but it's close and I'm not sure how much more it's going to shrink. It's 361 grams at the moment. It was 440 right after the last layer.
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Isnt there a recommended thickness? I think the recommendation for a top-up after a few months is only in case the sinew shrinks to below the required thickness after it has cured. If you've got the right amount on there then you probably shouldnt add any more, I'd leave it cure and once its all done you'll accurately know what to add or even sand away
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There's just one spot in the eye that's iffy and I really think it will be OK. It's almost 4mm thick there and I'm kinda going for 3mm. I just don't know how much more it's going to shrink.
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It won't 'shrink' much more. Just the bonds getting stronger with time now.
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OK it's officially curing now. Nothing for at least a few months so all there will be on here is some random questions about hornbows. For example.
When I do get to close to tillering do I reduce the sinew to get the thickness taper even on both limbs first? I ask this because in the book Adam only mentions reducing the horn when tillering. Is there a reason for not reducing the sinew as part of the tillering?
I can make the tepeliks now. It says to make them with the about same radius as the strung bow. How do I guess at this radius?
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You can sand the sinew lightly to flatten it but anything more is not advisable. You want long untouched sinew fibers on that outer layer covering the whole sal and kasan eye area. Fill in any voids rather than sanding down to remove them.
Reduce the horn to get a perfect taper before bending.
Good question with the teplics :) To be honest I don't use them anymore. I prefer to open the bow with the notched stick(name?) initially. to check for twist balance, bend etc. Then once it looks good I use a pegboard to get to brace. For the heavier bows that are too strong for the pegboard I made a bow press with a boat winch to do the pulling haha. Stringing your first hornbows for the first time is quite a heartrate raiser....
The pegboard is made from glued up ply at 2 inch thick. The posts are high density plastic rod 1 inch diameter, with soft leather wrapped around. A 4 inch section of ply to act as a saddle for the handle. Multiple holes drilled so the bow can be bent progressively.
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You can sand the sinew lightly to flatten it but anything more is not advisable. You want long untouched sinew fibers on that outer layer covering the whole sal and kasan eye area. Fill in any voids rather than sanding down to remove them.
Reduce the horn to get a perfect taper before bending.
OK, might be a problem here. I know the sinew is thicker on one limb than the other. I'm not sure by how much, can't remember right now. Should I reduce the sinew to an even thickness(a little thinner than finished) and apply a final continuous layer? Probably use the Korean method.
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Yes make sure the sinew is even. If you have different amounts on the limbs it will season funny.
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OK. now how about the sinew wrapping around to the belly. I found this to be the most difficult part of sinewing. In the tillering section Adam says
The scraping of the belly or the sides of the bow is done in such a way that the roundness of belly is always maintained. There is no need to worry about exposing the wood of the core at the edges of limbs, but the belly should still remain round with the sinew layer kept as the widest surface on the back of the limb.
Karpowicz, Adam. Ottoman Turkish bows, manufacture and design: second edition . Adam Karpowicz. Kindle Edition.
If there is no reason to worry about exposing the core, why do we bother wrapping the sinew around the sides?
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You can remove the belly sinew when tillering. You can then add the belly sinew once the bow is tillered. Personally I think as long as there is sinew on the edges you are good. You will have the devils own job trying to get it to stick to the horn belly and stay stuck anyway.
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You can remove the belly sinew when tillering. You can then add the belly sinew once the bow is tillered. Personally I think as long as there is sinew on the edges you are good. You will have the devils own job trying to get it to stick to the horn belly and stay stuck anyway.
Hide glue doesn't hold well to horn?
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Are all applications the same? ;)
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Are all applications the same? ;)
I'm sorry, I dont understand.
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To glue horn effectively with hide glue first you must make the surface smooth. Then size it with 5% glue around 20 times in warm conditions. Then heat it to 40 degs and glue with 30 - 35% glue whilst everything is hot. Solid clamping is a necessity.
Now try and do all this on a horn belly that is already glued up into a bow.....don't get me wrong it is possible but personally I've found it not worth the bother. The sinew is in compression and tends to lift off the belly. Also when tillering unless you are super lucky and the bow doesn't need any tillering you end up removing it anyway. As long as the sinew is the correct thickness on the sides and is blended into the curve of the belly I haven't had any problems with no belly sinew.
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So if this bow turns out to be ,say, 55#. 10# too heavy. If I only have 1/8" of horn(possibly less because of the grooves) will I be able to get it down to 45# by scraping the horn or will I have to narrow the sal/eye? If the horn gets too thin will it buckle? How thin is too thin?
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How long is a piece of string :)
If you followed those dimensions I gave earlier for the 45#'er you will be ok.
2mm is about the mimimum for horn thickness.
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Getting close to time and now I'm starting to have doubts. I had to remove quite a bit of sinew to even it out. Is it too late to add one layer of full length sinew? Would it stick well?
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I have only sinewed 1 bow so I am no expert but I think you can apply a new layer of sinew at any time as long as you do everything properly. My question is whether you need to apply any more - if the calipers show the thickness is correct then aren't you best leaving well alone?
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This is why you need to weigh, very accurately, the sinew bundles. Make absolutely sure they are the same for both limbs. Apply them evenly and you won't have problems with too much ,too little etc...
Another very important part is to make sure there is the same amount on either edge of the limbs. If not then the bow will twist as it's drawn and you won't be able to get a straight bow out of it.
The last layer of sinew must not have 'violations' where you removed some. The last layer absolutely must be one whole layer. I know you can get away with it on wooden bows but not hornbows, the ends will lift, maybe not straight away but over time they will lift.
When I've taught friends to make hornbows I tell them from the very start do not expect your first attempt to be a fantastic shooter....even with somebody on your shoulder it is all too easy to make a mistake! It's a journey learning to make hornbows and the beginning can be frustrating! There is no magic to it BUT it can take a while for all the subtleties to sink in and realise how important ever single step is :)
Anyway good luck and don't stress about it!
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But is there any problem applying another layer now?
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File/sand everything down to perfectly even thickness both limbs. Do the finishing work to almost final thickness with 60 grit paper, then finish off with 80/120grit and the freshly exposed sinew will stick properly.
Make sure to size with either very thin 5% glue or hot water just before laying down the new stuff. Also where you are working should be hot to avoid any adhesion problems.
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Thanks. It's going to have to wait a couple of weeks to get the shop warm. :D
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I put on another layer of sinew yesterday. I'm not sure if it really needed it or whether I'm just too chicken to start bracing it ;D. I put 84 grains on each limb. It now has a smooth layer of continuous fibers. With the existing sinew being 90% cured how long do you think I have to wait for this to cure? The full 3 months again?
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How would you even brace something like that!!!!
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Now you know why I'm chicken. I can use either a peg board or I'm thinkin I'll modify a broken 3" sgueeze clamp(like the Irwin Quick grip) I've got.
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Wow, quite a project! I have no intention of ever building one of these, but it's fascinating reading. Hope it works for you!
T
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2 weeks is plenty and yes it was necessary. As I said before broken fibers, ends of fibers in the sal will lift.
Peg board is the way to go. It allows you to work under full control,no danger and it is good for the bow.
Whilst they seem daunting to begin with....that is the wooden bowyer in you! Don't worry, be happy and just do it haha! It either makes it or it doesn't and that is mostly already decided by your previous work. Hence why every step is very important to get right. The final working bow is simply many,many relatively simple steps one on top of the other that add up to the whole.
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Do you clamp the handle on your peg board so it won't move? Where do you locate the pegs? A picture would be nice :D
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I just noticed that Adam suggests painting the back with a layer or two of glue when you've finished sinewing as an aid to finishing. Wouldn't that excess glue just crack?
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Ok, I'll try and take a picture of my board today. I'm busy doing a complete re-wire on the whole house at the moment but I should be able to take 5 mins later.
No need to clamp the handle as the bow keeps itself there.
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That glue layer fills any low spots but also serves as a 'sizing' for covering with leather. I personally only give it a cover with some 20% glue once.
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Is there a best tool for feathering out/ smoothing the sinew? It has a tendency to fray.
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It's time. After the last layer of sinew dried the tips were touching. I made a pegboard which I now have to remake after seeing where the holes actually have to go. :D Anyway here are the first two stretches. Should I leave it on the board for some time to stretch out? Adam suggests "working" the bow as you stretch it out. I guess I could do that in between pegs. Is this a long term project? Like stretch it out over a few days or? It wasn't very difficult to get it open this far.I don't see any sign of twisting but I'm not sure it would show up on the peg board.
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I puttered away at it. I decided to try the tepliks as my pegboard wasn't giving me a warm fuzzy feeling ;). I can still go back. The fades seem stiff, there doesn't seem to be any bend in the first 5" from the centre but Adam says there's not supposed to be much bend so maybe it's OK. You can see where it starts to bend in the middle of the teplik. From the teplik out it looks horrible. I think there is too much reflex in the sal and I'm wondering if I can use heat to sort that out. Adam says not to heat the sal because you'll lose reflex but that's what I want in this case. You'll notice that I have to use a pipe to bend it so I don't think it will come in too light if I take some reflex out. The other limb behave exactly the same and the thickness taper looks OK on both.
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i would wait for a second opinion before heating it
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The teplics are the wrong shape. They should have a slightly tighter radius than the strung bow. Don't heat the sals there is no need whatsoever and you will reduce the performance too much. This is what I meant about breaking cores :) Don't bend the bow over them.
I'm sorry but I was going to take some pictures of my pegboard for you. All the other stuff i'm busy with kicked that thought out of my mind....I will definitely take some pics for you as soon as I get back in from my morning run.
You want the pegs to sit at or just past the kasan eye.
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Here are some pictures.
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The teplics are the wrong shape. They should have a slightly tighter radius than the strung bow. Don't heat the sals there is no need whatsoever and you will reduce the performance too much. This is what I meant about breaking cores :) Don't bend the bow over them.
I'm sorry but I was going to take some pictures of my pegboard for you. All the other stuff i'm busy with kicked that thought out of my mind....I will definitely take some pics for you as soon as I get back in from my morning run.
You want the pegs to sit at or just past the kasan eye.
Thanks for the picks. :D
I figured the tepliks were the wrong shape but how do you know ahead of time what the strung shape is going to be?
Don't bend the bow over what, the tepliks? I thought that's what they were for??
If I don't heat them, how do I get rid of the ugly bend.
I've had trouble understanding the tillering process with these bows.
So with the peg board you don't use tepliks at all and the kasan eye is the thinnest part of the limb?
Sorry for all the questions but this is the important part, right? ;D
So if this was a peg board the pegs should be where the black dots are?
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Indeed.....you have hit the nail on the head with the teplics shape! I can dig out a pair I have used in the past and take some pictures. Another way is to scale up a picture of a strung bow of similar length to yours.
Yes I mean those teplics. That is what they are for but they must be the right shape or else you run a strong risk of breaking the core under the sinew.
I don't see what ugly bend you mean. There is nothing wrong with the unstrung shape. The sals will straighten with use. Do not heat them ever unless there is twist in them when the bow is strung/drawn. However it is unlikely that the bow will be twisted in the sals. Normally it is the kasan eye.
When I use the pegboard I simply bend the bow on it progressively further, checking for twist/weak spots as you go, until you can string it. Once strung any twist will be apparent. Correctly shaped teplics allow the bow to be strung for the first time with good control. If a new bow is twisted and the limbs out of balance the first time it is strung it will act like a living thing haha. The teplics get around this. I find now that I have done a few of these they are generally pretty close to good tiller the first time I bend them so the process tends to go easily enough. For my latest round of heavy bows I have made a press using a boat winch.
Right :)
And finally yes that would be about right for the peg positioning.
Good luck and ask away if you think I can help.
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I "tried" the shape of the tepelics ,..... bending the future core only - same width and thickness of the bamboo core around it... around 5mm bamboo core
The core survived .... so there was no problem with finished bow too during the first bending :)
Indeed.....you have hit the nail on the head with the teplics shape! I can dig out a pair I have used in the past and take some pictures. Another way is to scale up a picture of a strung bow of similar length to yours.
Yes I mean those teplics. That is what they are for but they must be the right shape or else you run a strong risk of breaking the core under the sinew.
I don't see what ugly bend you mean. There is nothing wrong with the unstrung shape. The sals will straighten with use. Do not heat them ever unless there is twist in them when the bow is strung/drawn. However it is unlikely that the bow will be twisted in the sals. Normally it is the kasan eye.
When I use the pegboard I simply bend the bow on it progressively further, checking for twist/weak spots as you go, until you can string it. Once strung any twist will be apparent. Correctly shaped teplics allow the bow to be strung for the first time with good control. If a new bow is twisted and the limbs out of balance the first time it is strung it will act like a living thing haha. The teplics get around this. I find now that I have done a few of these they are generally pretty close to good tiller the first time I bend them so the process tends to go easily enough. For my latest round of heavy bows I have made a press using a boat winch.
Right :)
And finally yes that would be about right for the peg positioning.
Good luck and ask away if you think I can help.
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I "tried" the shape of the tepelics ,..... bending the future core only - same width and thickness of the bamboo core around it... around 5mm bamboo core
The core survived .... so there was no problem with finished bow too during the first bending :)
Indeed.....you have hit the nail on the head with the teplics shape! I can dig out a pair I have used in the past and take some pictures. Another way is to scale up a picture of a strung bow of similar length to yours.
Yes I mean those teplics. That is what they are for but they must be the right shape or else you run a strong risk of breaking the core under the sinew.
I don't see what ugly bend you mean. There is nothing wrong with the unstrung shape. The sals will straighten with use. Do not heat them ever unless there is twist in them when the bow is strung/drawn. However it is unlikely that the bow will be twisted in the sals. Normally it is the kasan eye.
When I use the pegboard I simply bend the bow on it progressively further, checking for twist/weak spots as you go, until you can string it. Once strung any twist will be apparent. Correctly shaped teplics allow the bow to be strung for the first time with good control. If a new bow is twisted and the limbs out of balance the first time it is strung it will act like a living thing haha. The teplics get around this. I find now that I have done a few of these they are generally pretty close to good tiller the first time I bend them so the process tends to go easily enough. For my latest round of heavy bows I have made a press using a boat winch.
Right :)
And finally yes that would be about right for the peg positioning.
Good luck and ask away if you think I can help.
You could do it that way but only with a thin core or bamboo. Also when you add horn and sinew the taper rate will change and so the curve too.
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question... how do you tiller a horn bow???
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So far so good. How does this look? How do I stop the bow from walking back and forth as I move each limb to the next peg? As I bend the limb the handle slides across the saddle. You can see where I clamped the block to stop that but it really didn't help. I also put a top on the saddle because I don't want this think loose in my shop. I have to put a 1" pipe on the limb to bend it. I really can't see me pulling this thing.
Also with this much tension I can't see any way this is going to twist. How can I tell if it wants to?
Should I be letting it sit like this for some length of time before bending it more?
Why do I feel like there is a bomb in my shop ready to go off? ;D
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I shaped the saddle lid to match the top of the handle and that stopped the sideways movement.
I cleaned up the horn a bit and found a lengthwise crack. I can feel it with my fingernail. Is that it, am I finished? Or CA and continue? I'll check Adams trouble shooting section.
PS Adam says to use CA so I did that. I'll wait for your comments before I continue.
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Yes it does tend to feel like there is a bomb about to go off when tillering these bows haha!
You cannot judge the weight until you have a string on (or a lot of experience!). The extreme string tension is one of the reasons for better performance. High initial energy storage. This is what you can not do with wood. A fair amount will pull out once it is strung for a day or so and then you will be left with the true amount of 'tillered' reflex.
The crack isn't ideal because it appears to be angling through the limb not running back to belly. If it was a crack induced during drying they tend to be the later and not a problem. I personally don't like the look of your crack but all you can do is proceed with tillering and cross your fingers.....
Tiller-wise the left limb looks ok but the right has a weak spot out of the handle. Do not pull it further until you fix that. Limb strength relative to each other is something you will have to judge by feel until you have it strung. A 2nd cut file and 60 grit on a block is the way to go to sort the tiller.
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The left kasan eye also appears a little stiff. Check thicknesses relative to each other with calipers, if there is no difference in thickness heat the left eye and open further.
You may have no twist - if not do a little dance and congratulate yourself. It will certainly be apparent when strung if there is any.
Yes you can leave it on the pegboard for an hour or so before removing any material/moving onto the next step.
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Black arrow too weak? Red arrow too stiff? Is that where you mean. I'm having a tough time seeing them.
Do I tiller this like a wood bow as far as dealing with the weak spot. ie weaken the rest of the limb and then make the other limb match? Or do I just weaken the same spot on the other limb?
I'm not liking the way the crack is running off to one side although it does look like it's straightening out some. I think I heard it crack. I'll carry on :)
PS I had taken it off the pegboard and like a fool I hadn't marked left or right. The holes in the tips are not symmetrical so I might sort it out that way. I'll mark them now. >:(
PPS It's -6C here and the RH in the shop is 35% before heating it up so I may take some time off until it's a little more humid.
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Adam suggests not tillering if the RH is below 30%. Does this suggest that things may go easier if you kept the bow in a controlled environment of 50-60% maybe even 70% for the tillering period?
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Just wondering, this is the bow at rest. Should it be further open? I thought there was mention somewhere that the tips should be 90° to the belly at this stage.
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Humidity that low is a dream to me! I wouldn't worry too much about the humidity but yes it is useful to keep it equilibrated at 50 - 60 rh.
The belly cracks can be caused by the sinew drying (it also shrinks laterally)but yours looks like it may have been there all along. Did you put the linen patches on the belly during curing? They do help but a bit late now.
Yes the weak spot id where you have marked.
Yes treat it like a wood bow regarding weak spots. Even material removal on the good limb and either side of the weak spot. It can be helpful to put a piece of paper/card under the bow on the pegboard , bend the bow and trace the outline onto the card. Make corrections then repeat. The card will help you spot the differences between corrections and compare one limb to the other easily.
Be careful with any weak spots as they can cause the core to break.
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And yes you should open it out with heat so the tips are pointing straight up when at rest. It's tricky at this point because the bow is still holding reflex,some of which it will lose by being tillered to full draw. Chicken or the egg?
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And yes you should open it out with heat so the tips are pointing straight up when at rest. It's tricky at this point because the bow is still holding reflex,some of which it will lose by being tillered to full draw. Chicken or the egg?
OK My plan is to heat it the red marks to 50c. I'm thinking it will make it easier to tiller as I won't have so much reflex, won't have to bend it so far.
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Have you used a hair drier for heating bows. I just tested one and it has a setting that is very close to 50°c. Can't overheat it but may be drying? Seems like the way to go to me.
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No I haven't so can't really comment. I use an electric hotplate. I got mine for very little money and it has served me very well. Remember it is the core you need to get hot enough to bend so slow and steady is best. It can take 20 mins heating with my set-up to get upto temperature. I also use electric heating pads wrapped around the limb.
Its best to do the corrections and let it sit for at least a few hours with the tillering stick in place and spread apart far enough to take into account any 'spring-back'.
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Remember it is the core you need to get hot enough to bend so slow and steady is best.
Really? The core at this spot is only about 3mm thick and heating wood to 50°c(122°f) isn't warm enough to do anything. Am I missing something?
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Adam says to take very little horn off when scraping. Is that just a general tillering statement or are these bows a lot more sensitive to horn removal than a selfbow is to wood removal?
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The core gives the bow its shape. Simple :) If you don't get the core hot enough the shape won't change.
Common sense - go slowly :)
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OK bring this up to where I am
I spread the limbs to about 24" apart on the pegboard. I heated the kasan eyes(at least I think it's the kasan eye) Used a hair dryer so I wouldn't overheat it. Heated about 3" to 50°c (125ish f) and held it there for 30 minutes. Heat was checked with an infrared thermometer. Did both limbs at the same time. Waited 2 hours for it to cool off. Took it off the pegboard and it went right back to where it was :( :( Put it back on the board and spread the limbs to about 30" apart and repeated the whole procedure but used a little more heat, 55°c and same time. This time I left it on the pegboard overnight and when I took it off in the morning it didn't look too bad but not as open as I thought I wanted. There was 15" between the tips. Went and did a few chores for an hour, came back and it had closed down to 12". I just looked at it about 5 hours later when I took these pics and it's closed down to 10". I don't think I made any progress with the heating at all. Is this supposed to happen? The picture showing me heating it was just staged, I actually heated it yesterday. I haven't done any actual tillering yet. Makes me wonder why I didn't keep it from reflexing so much when I was sinewing it. Very frustrating, especially when the damn thing is probably going to break anyhow.
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If the bow has been in 35% rh it will be hard to correct. I have no problems with my electric element. For the sort of corrections you are attempting it would take about 20 - 25 mins per limb.
As I said above if you don't get the core hot enough you won't change a thing.
So your heating cannot have got the areas hot enough.
I wouldn't heat it on the pegboard either- it will lead to uneven heating. You should be heating it with the tillering stick in place. Don't try to re-invent the wheel!
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If the bow has been in 35% rh it will be hard to correct. I have no problems with my electric element. For the sort of corrections you are attempting it would take about 20 - 25 mins per limb.
As I said above if you don't get the core hot enough you won't change a thing.
So your heating cannot have got the areas hot enough.
I wouldn't heat it on the pegboard either- it will lead to uneven heating. You should be heating it with the tillering stick in place. Don't try to re-invent the wheel!
When you say 20-25 min per limb it sounds like you're doing one limb at a time. Are you?
I'm not trying to reinvent the wheel, I know my limitations and I could see myself overheating this thing if I tried to heat it over a stove. The hair drier seemed like a safer way. I'm going to put it in a plastic bag with a wet rag for a few days.
I'm making a tillering stick. I realised yesterday that the pegboard was less than optimal for showing twist.
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I meant by heating it on the pegboard. You need to be able to move it.
A normal stove is likely too hot. The hotplate elements I mentioned are very gentle and don't dry the bow out too much either.
Heating with the tillering stick in place must be done on both limbs equally or else things will start going south. I heat each limb for 30 secs then swap, 30 secs, swap.
I like wrapping both limbs in heating pads first to pre-warm them, then go to the hotplate.
This part can be frustrating but patience is key. You need to develop the feel for a lot of things before you can do the corrections quickly. Over heating is easily done and non reversible so much better to work your way upto things slowly.
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Just to clarify things. If I get this thing open into a "C" shape should it hold that shape forever? I had it out to 19" between the tips, left it overnight and within a few hours of taking the tillering stick off it was down to 15" and the next morning it was 11". Should I be leaving the stick in. I'm heating it on the stove, doing everything I should, I think. I'm heating the horn side until the sinew is about 120°(50c) and holding it at that temp for 20-30 min. That's actually overheating the belly side a bit. Adam says to spread the tips to about 24" and I'm spreading them to 30". I left it in a bag with a wet cloth overnight. I'm about out of ideas.
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steaming??? try that?
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Don't think I'd want to steam something that is 20% hide glue.
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Yes steaming may be a very very bad idea ;)
You aren't getting it hot enough if the core isn't relaxing. Heat takes a good time to 'soak' into the core. The surface temps shouldn't be exceeded but that isn't what matters.
The reason to reduce the reflex is that the bow will be much easier for you to tiller. Less strain and much less chance of twisting around the kasan eye.
However it is possible to continue tillering without altering the shape. Obviously once its strung/drawn it will naturally start losing some reflex (likely to be mostly in the sals tho).
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I was heating from the belly and the back was 45-50°. The core had to be 50. I want to try the heating pads but the only ones I can find are 12x15". A bit cumbersome for heating a 4" length of bow. I also only have one and another would cost $25.
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well maybe just heat it at a lower temp, longer. but i dont have that time so i get to see how you do it. ;) ;D
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I'm trying this. The light bulbs are heating the belly to just under 50°c. I fiddled with the distance until it was right. Now I can just let it soak. I'm checking the temp every 5 min. It's been going a half hour or so. It's just hanging on the pegboard. Maybe kinda Rube Goldberg but I've tried all the other ways I can find.
I let it heat for 1 1/2 hours. The back was at 45+°c for most of that. See what tomorrow brings.
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Bownarra, I remember you saying way back that something about the shape of this bow was going to cause me trouble down the line. This is a picture from right after I glued the horn on. Is it possible that the glued in reflex in the sal area is whats stopping it from straightening out as much as I want. I've done everything you've suggested and more and it doesn't want to open.
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I decided to bend it and live with the consequences. It doesn't look too bad to me but what do I know about these things. Should I move the peg holes out a little further? I really think I've just got one more hole to go to get to brace height. I'll paint the board black so I can see things a bit better. :D
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Yes what you've done would have been my next suggestion! Bend it further to see what is going on. Yes I think you are right about the sal reflex/core shape.
Now that it is bent on the pegboard the kasan eyes have opened, can you see that area bending when you bend the bow on the board? The sals look to be bending a little too much close to the handle but with the reflex in the sals having to straighten out first it may be misleading. If you leave it sat like this for a while the temporary set you will see when you take it off the board will tell you where it is strained or not. Having the bend a little closer to the grip isn't a bad thing really as it will make the bow a little more stable, easier to string and won't stack as early. You do get more set in the inner limbs but that isn't a big deal.
Pegboard holes look to be in a good place on the bows limbs. I would drill two more sets of holes. One as far down as you can drill and an intermediary one.
You want to brace it at around 7 1/2 inches initially. They can be a bit 'wild' on first brace! Have the sections of inner tube to hand....
Once you add the holes to the pegboard take some more pics. I think the next set of holes will help to reveal how to proceed.
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I'm following closely, and every post has me waiting with baited breath!
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OK here ya go, can you see behind my hand in the first pic how much more the "eye" is bending compared to the next pic when it's on the peg. The same shows on the third and forth pic only not as much. I'm thinking that when I get it braced the left eye will be bending quite a bit more than the right. Leverage. I don't think the pegs allow the true shape to show. That's why I drilled the outer holes.
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Does this pencil mark look about right for the nock? It's 7 cm from the the kasan tip bend apex.
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Here's one with the pegs in the outer position. It's quite different and kind of unnerving.
I'm thinking I have to scrape at the red marks. Just in between the weak spots on the left limb and more or less the whole thing on the right
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Before I comment on the tiller. Could you measure the limb thicknesses every 5cm on both limbs and post what you've got.
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It is so cool watching this unfold (quit literally!) DC. Thanks for sharing your process. It's fascinating.
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It is so cool watching this unfold (quit literally!) DC. Thanks for sharing your process. It's fascinating.
Well it's pushed me to the limit a few times. I'm glad I started this thread otherwise I may have abandoned it. Pride does have a use sometimes ;D ;D
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Before I comment on the tiller. Could you measure the limb thicknesses every 5cm on both limbs and post what you've got.
OK I hope you can read this. I got the crud and just don't feel like typing a bunch. Left hand side is what I measured. Then to save time I did a little fixing and the right hand side is the after. The picture is after. The discrepancies were minor most were just little ridges in the sinew that I missed. I seem to be having computer troubles so if I disappear for a few days I haven't jumped in front of a bus or anything. ;D ;D
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It is so cool watching this unfold (quit literally!) DC. Thanks for sharing your process. It's fascinating.
what he said. I've learned so much from this thread, thanks for posting!
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I think you should really concentrate the bend on the first 1/3 of the limbs. Now the outer limbs are bending way too much. I hope you got some poundage left on it. The beginning shape doesn't really show much kasan eye angle, so the final bow wouldn't show it that much anyway as a more "normal" turkish shape.
It looks like the bow in general likes to bend, even the kasan parts so you have gotten past the worst part!
Here is some measurements of some of my bows, a typical turkish: limb next to handle 13mm thick, mid sal (most bending part) 12,2mm, kasan eye 11,7mm and from there quite fast growing to kasan 15mm.
Just to remember: horn and sinew will stand a lot of bend. You will get speed (efficiency) and balance in the bow if you concentrate the bend more. Even a momentarily hinge that would "destroy" wood bow, wont do much to hornbow. Also, if you make the bow bend too much from outer parts, you will end up keeping an awful lot of reflex and the bow will be hard to brace.
Anyway, its close to brace, you will do fine. :)
Oh and about the nocks, 55-70mm from the end of kasan was normal length. So what ever you choose. Of course you can scale it to your liking, for short bow (40") a 55-60mm is fine, longer (46") 70mm. Crimean tatars were longer bows with lengths about 46-54" so they had quite much longer, 80-90mm nocks.
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I thought I would put a full group of pictures on this page. I leave the stretcher bar in all the time now. I can see that the right sal has more reflex bend than the left.(Edit-or maybe it is in the eye) What should I do about that if iI shouldn't heat the sal. The weight will be what the weight will be. I can only pull 40# and it feels like it will make that but what do I know. These things change a lot as you bend them.
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I thought I would bring Bownarra's measurements back here
"Here are the measurements from my 40ish# bow. 121cm.
Center - 33mm
5cm - 26mm
10cm - 14mm
15cm - 10.4mm
20cm - 9.6mm
25cm - 9.1mm
30cm - 8.9mm
Kasan eye 35cm - 9.5mm
40cm - 12mm
45cm - 13.5mm
50cm - 14.5mm
Base of tip 52cm - 17mm"
I'm a little thick(that's well known)at the 15 and 20 cm marks so that kind of goes with J's comment. I'm just not confident that I have enough horn. Maybe I can take a bit of horn and a bit of sinew? I heated the eye on the right limb and took a little reflex out. We'll see if it holds. It looked better to my eye. I'm not doing much, still got the crud.
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Well, its not an easy task to make a hornbow. I've broken plenty :D.
In case you run out of horn in sal section, basically the only effective thing to do is to add sinew to the outer limbs. Then while drying, make an effort to reflex the outer limbs as much as you can.
Other choices are to deflex bending parts or narrow them. But those doesn't really add much.
I think you have good chance of adding 2mm more sinew (as a kasan ridge). Do it in two rounds and roughen the existing sinew back properly.
Some old bows actually had even a 4-5mm thickness of sinew in the kasan ridge. Adam K. writes in his book that if you run into this kind of tillering problem or bow coming under weight, under sinewed or such, adding sinew layer after long curing is still viable option.
After this extra layer, i wouldn't wait more than 2 weeks to continue tillering.
If you can take of sinew from sal sections, after that you would need to put a full layer of sinew on top of sal, to bind everything together. But that is a viable option too. Actually, you might be best of by using both, taking of sinew from sal (if there is too much in the first place!) and adding sinew to kasan.
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If I add more sinew the DW will go up, right? If it goes over 40# it's just a wall hanging for me, I can't pull it.
" Here is some measurements of some of my bows, a typical turkish: limb next to handle 13mm thick, mid sal (most bending part) 12,2mm, kasan eye 11,7mm and from there quite fast growing to kasan 15mm. "
What is the DW of this bow?
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Is a tillering tree ever used?
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As i described, you can take of sinew from sal and add to kasan. Cause now the balance is wrong. Just an idea. This wont raise the draw weight, but balance the bending.
If you already have only the minimum 2mm of sinew in sal, then the problem is your core. Its hard to go and tiller your core at this point.
I gave those measurements as a example of proportions, that bow should be about 90-100 pounds when tillered.
Tiller tree is used when you get to brace the bow and have it straight, so it wont unstring itself.
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When I was bending it to measure the string the crack in the horn extended itself about 2". The part that I had previously CA'ed is still fine. The crack continued straight down the bow so I CA'ed the new part. But,,, right where the new section of crack is the limb now has a sideways dogleg that I'm pretty sure wasn't there before. I've been watching for twist because I was proud of myself for not having any. This doesn't look like twist, it looks like a sideways bend. But I guess it could be twisting. I'm trying to get rid of it by heating the eye.
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I got the twist/ sideways bend corrected with heat so I tried to brace it this morning. The left limb went into full bend and the right limb went into full reflex, so it was "S" shaped. The rubber band would have held it I think but it was such a delicate balancing act. If I straightened the left limb by squeezing the limb and the string it would pop through and the right limb would go full bend and the left would go into reflex. This is obviously not right. Maybe not enough brace height? I didn't have enough hands to measure it while I was playing with it but I took notice of where it was and it was about 8". That's in the ballpark according to Adam. It's like each limb is ready to oil can and any push will send it one way or the other. I'm pretty sure the left is the weakest. I was planning on resinewing but now this is happening. Not sure if I want to mess with it until I get an idea of why it's flopping back and forth.
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If you cant stop the excessive bend by hand, its quite apparent that the tiller is off then. You shouldn't run into this kind of problem if you let it be freely on the peg board and it stays balanced. Is your peg board 100% symmetrical?
Try to have the pegs as far on the tips as possible to mimic being braced with the bowstring.
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Peg board is symmetrical. It doesn't do it on the pegboard. The pegs are right in the tip bend and I think there is enough friction to stop it. It happens as soon as put the tension on the string and remove a peg. I've been looking at videos of people shooting hornbows and to me it looks like all/most of the bend occurs in the inner portion of the sal. The outer part of the limb never seems to go past straight. Mine does(this goes back to your earlier comments) and that gives the limbs the opportunity to "oil can". Mine is bending more like a conventional bow. I've been looking for progressive pictures of drawing a hornbow but haven't found any yet. I think if I stiffen the outer sal/ inner kasan eye area I think it would solve the problem but that would entail putting thickness where no one seems to put thickness. The only thing I can think of is that the combination of leverage and thickness make the inner part of the sal weaker but still thicker so the limb still has taper along it's length.
PS I just looked at a picture in Adams book and it looks like the whole sal bends evenly right out to the kasan eye which doesn't quite straighten out at FD. Now I'm thinking that when I made this I wasn't really sure where the eye was. I put reflex in the sal rather than the eye. So now the eye is bending too much. I'm stripping out the last of my long sinew so I'd better get this right.
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OK here's the new kasan ridges. The dark line is shadow. It's a nice smooth blend.
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After about 3 months, while the bow still dries, it can be worked further to shape the sinew. It is done first with a file to flatten the back, or, if a flight bow to give it a slightly rounded shape. The edges are also made round, but still overlapping the belly (see the chapter on cross-sections). Sinew is also shaped on the kasan section and the excess is removed from the tips. Then the bow is sanded again to eliminate the file marks and checked with a caliper to make sure the thickness of sinew was sufficient.
Karpowicz, Adam. Ottoman Turkish bows, manufacture and design: second edition . Adam Karpowicz. Kindle Edition.
If I can do all this to make the sinew smooth why can't I scrape a bit for tillering?
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Basically you want to keep the sinew fibers intact. What ever you choose to do, just keep this in mind. Small scraping such as just making the back even and flat is minor. I wouldn't personally go tillering from the sinew back.
If the bow ends up too heavy you can always equilibriate it in 60% rh or so and then heat off the reflex. I think you tried this but the moisture content of the bow makes a big difference.
I think Adam has in his book bows half drawn. Basically the kasan doesn't bend at all.
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Filed down the fade quite a bit and took a layer off out to the kasan. Then I put a new thinner layer of sinew where I had filed. Now wait a few weeks,,,, again :)
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sorry I haven@t checked in for a while!
yOU MUST NOT LET THE BOW 'FLIP FLOP' oops caps lock on haha
As I said it will be 'alive' when you first string it. You should have everything to hand eg. the inner tube pieces. A piece of cord works too.
It is doing this because it is a light bow. Simple as that. Heavy bows are much,much easier to tiller. To reduce the tendancy to do this you should let it sit on the pegboard for a few days (only once it looks nigh on perfect). The light weight bows need a lot of time to settle to the string. A light weight bow I tillered for someone else took a week being strung before it settled down. Its bending sections were far too long. Don't make any judgements about limb strength relative to one another until you are 100% certain. If you make even small mistakes with material removal you will be chasing your tail.
DO NOT tiller from the sinew back - a light flattening is ALL you should do to the back. The same rules apply as on a wooden bow. These bows are also way more strained. I seriously would not want a hornbows back to fail when I had it drawn......
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It is doing this because it is a light bow.
Do you think you could explain that somehow, it makes no sense to me. To me that's like saying a rat trap will work and a mouse trap won't. Exactly the same design but the rat trap has more tension.
So to me. Not "as simple as that" :D
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It is doing this because it is a light bow.
Do you think you could explain that somehow, it makes no sense to me. To me that's like saying a rat trap will work and a mouse trap won't. Exactly the same design but the rat trap has more tension.
So to me. Not "as simple as that" :D
Perhaps it's because a heavier bow will stress the materials to their max faster, And stretch the back more and faster so you have less time of it getting broke in. Like a string, when you stretch it, the string stretches to it max faster on a heavy bow, than it would on a lighter bow, so as time goes on, you need to add a few twists to the string as it gets broken in over time, vs a heavy bow that stretched the string on the first couple draws.
Just a wordy guess on my part. I'm certain a knowledgeable reply would mean more, but I can see how that could work.
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I said 'simple as that' because that is the only reason why it is 'flip floping'. None of the other stuff.
Nothing like your mouse/rat trap analogy ;)
Thinner limbs obviously have less material in them, most importantly less wood. Wood being by far the stiffest material in a composite. The wood gives the bow its shape and is generally the cause when a bow doesn't bend right or resists bending correctly.
Horn bows made with no core are very prone to this problem.
Light weight hornbows have to have thin component pieces however I like to go as thin as possible with the horn,2mm max with the sinew and leave the wooden core as thick as possible.
Trust me a 100# bow is a whole different animal than a 40#'er performancewise and ease of tillering.
Think about making a wooden kids bow. using 'normal' adult lengths/widths etc - say 66", 1 3/4" wide but instead of 50# only 20# how would that bow react to 'normal' belly tillering (compared to a normal adults bow). Sensitive eh? The wooden bow and the hornbows have little to be able to directly compare but this shows that IF you don't scale everything it WILL NOT act the same. Your hornbow isn't a scaled version of an original and couldn't be so you have to deal with these 'issues' which arise because of the differences.
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And so ends my hornbow thread. Can't say I'm sorry. I was getting pretty tired of waiting for this to happen. 9 months is a long buildup. So I think the problem was too much reflex in the sal. I looked at a lot of pictures before I made the caul and I was convinced that this is the way it should go. By the time bownarra pointed out the fault it was pretty much too late to do anything but forge ahead and hope. It broke before I got it to brace height. I had it bent a lot further before I resinewed it. This is the limb that the horn cracked on but whether that had anything to do with it, I don't know. I would not recommend making a hornbow unless you have a mentor. Even with Adam's book most of the time I felt I was groping in the dark. Thanks a lot to everyone that helped especially bownarra an JNystrom. I don't think I'll try again :D
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NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO :'( :'( :'( :'( :'( :'(
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If I have the ability, I'd supply you the material if I could somehow bribe you into making another. You have a certain level of mastery about everything I have seen you build. I'd love to see you do a follow up to this thread with lessons learned.
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I've got everything I need. I could soak it all apart and with any luck the core would still be good. I originally bought 4 pieces of horn. I just don't think the desire is there.
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Question for bownarra. There is no way to salvage this is there? Even if there was I'm still stuck with too much reflex in the sal. Should I throw it in the baby bath to soak it apart. At least get my sinew back.
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Sorry to see that DC.You may not believe it but some of us have been through this type long term and even longer failure conclusion before.
If there was a crack on the horn that migrated to the edge it probably was the cause.Every one has it's lessons to be learned.
I see your starting a different bow but a bow.That's what I did too.Get back on the horse.
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I'm sorry but i'd say that is the end for this one.
When soaking them it takes forever to get the horns off in one piece, even if you could the core/sinew is too 'floppy' to glue the horn onto properly. I would just try to salvage the sinew.
Sorry to see this happen. You have the patience - try again! It took me a few failures and many lonely hours in the shop (with Adam's book!) to get my head around them fully. Once you've made the mistakes the lessons learnt don't go anywhere in a hurry haha.
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Bummer, DC. Thanks for sharing your effort with us. I admire your patience.
T
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I'm sorry but i'd say that is the end for this one.
When soaking them it takes forever to get the horns off in one piece, even if you could the core/sinew is too 'floppy' to glue the horn onto properly. I would just try to salvage the sinew.
Sorry to see this happen. You have the patience - try again! It took me a few failures and many lonely hours in the shop (with Adam's book!) to get my head around them fully. Once you've made the mistakes the lessons learnt don't go anywhere in a hurry haha.
OK into the soak it goes
Bummer, DC. Thanks for sharing your effort with us. I admire your patience.
T
Thank WB. I think one of the reasons I didn't enjoy this as much as I could is my lack of patience. I like the "instant" gratification of a self bow. Another reason is not knowing what the draw weight will be. It seems that you have to make four or five of these things in order to have it turn out within the limited DW range. With a selfbow you can tiller it down to one pound if you want. With these it seems like there just isn't enough latitude(?). With this bow for instance there was a good chance it would fail because I got the design wrong. Even if I got lucky and it held together there was a good chance that it would be over my 40# DW. If it was it might as well be broken, it would be useless to me.
Anyway, I'm a bit bummed just because I failed but it's no big deal. I may make another but I don't think it would be a Turkish type. A little to unstable for me. maybe I'll try one like BowEd does. I do have two nice strips of horn. It would be a shame to cut them up for tip overlays :D
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Oh gosh yes, BowEd makes absolutely beautiful bows!
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sleek....I think you shot mine at Mo Jam 1 year at 15 to 20 yards and hit the 4" target right off the bat.
The making of bows from composites always amazes me as to the extremes a natural material will take along with their performance.Shooting them too.When made right they can seem almost indestructable.
There's a lot faster ways to get a very good shootable bow though DC like you said.
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That's a bummer DC. I hope you get back on the horse, you got this.
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sleek....I think you shot mine at Mo Jam 1 year at 15 to 20 yards and hit the 4" target right off the bat.
The making of bows from composites always amazes me as to the extremes a natural material will take along with their performance.Shooting them too.When made right they can seem almost indestructable.
There's a lot faster ways to get a very good shootable bow though DC like you said.
You recall correctly. Only twice before has a bow felt like it was part of me. Your arrows were tuned perfectly to your set up as well. Shooting that bow and arrow, felt like I was projecting myself toward the target rather than simply shooting a bow. It was satisfying to say the least. I'd take a loan against my truck for one of your bows.
Given DCs level of craftsmanship, attention to detail, coupled with his eye for art, he would no doubt craft a beautiful bow if he followed your style.
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You've got a lot more faith in me than I do :D :D
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For what its worth, this has been one of the most valuable threads I ever read, so thanks for posting all your trials and tribulations. Gutted for you this one didn't work out, hope to see you posting a follow-up thread one day.
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I'm going to have to read it again. Obviously I missed something ;D ;D ;D
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For what its worth, this has been one of the most valuable threads I ever read, so thanks for posting all your trials and tribulations. Gutted for you this one didn't work out, hope to see you posting a follow-up thread one day.
Yeah, if your done I say we archive it
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Too bad it broke DC. It happens, some break more, some less. I've glued up some 10 bows now and i've had very little success this far. Those longer bows (mongol, molche balka etc) would be good starter bows to get a hang off things. I don't mind the breaking though, since its so fun to build them. ;D Just need to see the light in the end of tunnel, it might just not be a train approaching...
About your bow, it is quite common practice to repair old bows that for some reason break/delaminate the horn belly. The way you do it is by first getting rid of the old horn by heat and wedges, or just by grinding it away. Then just the normal glue up with built up sizing coats, but the final clamping is crucial. The glue up shape of the limb should be as close to the other limb as possible. Its doable, but needs some skill also. I haven't personally done it, but i have some bows that would need to have it done.
If you don't like the bow in the first place, don't do it.
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The glue joint appears solid. There are bits of the horn still glued solidly in the bottom of the grooves. The horn just self destructed. I'm very impressed by the strength of the glue joint. I've convinced myself that the design was the problem so the other limb is probably just waiting to break. Moot point anyway I'm soaking the sinew off as we speak. It will be interesting to see what the actual thicknesses of the three layers are. I'm still debating what to do next but I don't have any perfect maple. I know of a tree and it's just about loose bark season so I may cut it. I would have to make a decision on what to make so I can steam bend it while it's green.
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I remember James Parker and his brother in law(disowned), Vinson Minor trying to brace for the first time James' first Asiatic horn bow(90#) and breaking it in the process. There were a few choice words blurted out.
Too bad your bow broke, DC. Lots of hard work in it I'm sure. Have you preformed an autopsy?
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I think it was my design Pat. I misunderstood and glued a bunch of reflex into the sal area when I glued the core and horn. This put too much stress on the horn when I tried to bend it. The horn just exploded. The inside of the horn stayed glued to the core and the outside popped off so I'm confident that the glue joint was good. I'm soaking it to get the sinew off. It's been soaking for 4 days now and the sinew is starting to peel off in big pieces. The horn is just starting to lift out of the grooves where it tapers right out. This hide glue is good stuff.
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Dc If the horn had been sound you would be amazed what a composite limb can take. Remember what Adam says about this subject. It wasn't the design.
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Dc If the horn had been sound you would be amazed what a composite limb can take. Remember what Adam says about this subject. It wasn't the design.
OK, now I'm confused. You mentioned early on with the build that there was a problem with my bow. Adam says not to put too much reflex in the sal. I thought that was it. On a side point when I was first trying to brace it and it flip flopped the limb that bent the most was the one that broke.
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I would probably say a combination. you said the horn was cracked. horn can take a lot of stress according to bownarra. the bow was stressed a bit more than it should have in the sal, but it should have still survived. so, crack + a little too much reflex on sal + limb twisting = broken bow in my mind.
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That design flaw (reflexed sal) would possibly lead to a delam of the horn core joint. The crack in the horn appears to have been the problem that caused your failure. Of course it is hard to say for sure from the other side of a computer! I never had the bow in my hands so take whatever I say with a pinch of salt :)
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Once everything is soaked off I'll post pictures of the horn. It may show something. I'm not 100% sure the cracked limb is the broken one but we'll see. The sinew is all off and one piece of the horn is off. I see what you mean by don't wait for the horn to soak off. The good limb is hardly showing any sign of coming off.
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I gave up waiting ;D here's some more pictures. Everything is oriented as it was. I'm pretty sure this was the cracked horn. I thought the CA would show but the horn flakes much like the CA when it breaks. It looks like it broke along the cracks but I think it would do that no matter how it actually started. The thing that makes me think that the horn broke is that all the pieces were still nicely glued in the gooving. It didn't just collapse like I've heard horn bows do. It went off with a bang and that centre piece was stuck in my rubber floor mat.
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yeah, to me that looks like compression failure in two places among the horn
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I was afraid of that...….!!! Its a real shame when at times during the build you think its going 100%, you devoted lots of time and brain energy, and it Freking breaks..! Those are days are when I really feel like throwing in the Towel.
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I was afraid of that...….!!! Its a real shame when at times during the build you think its going 100%, you devoted lots of time and brain energy, and it Freking breaks..! Those are days are when I really feel like throwing in the Towel.
It is disappointing but I knew when I started that the chance of success was pretty small.
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Carrying on with the post mortum. I looked at the core of the limb that I got stripped so it's just the wood. It's only 1/8" thick and then the grooves were cut in. That's from 7" out to about 13" from the centre. The horn is about 5/32" or there abouts. It's torn up so bad it's hard to get a good measure. The the sinew was about as thick as the horn and wood together but it varied more in thickness from the grip to the eye. It's hard to imagine that the wood added and structure to the bow. It's so flimsy. Do these numbers sound like they are in the ballpark? These are kind of averages so you can't get too much from them. It varies widely from the 1/3,1/3,1/3 but it was suggested that more sinew may be better for a beginner.
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yeah, to me that looks like compression failure in two places among the horn
[/quote
Where are the chrysals then?
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Carrying on with the post mortum. I looked at the core of the limb that I got stripped so it's just the wood. It's only 1/8" thick and then the grooves were cut in. That's from 7" out to about 13" from the centre. The horn is about 5/32" or there abouts. It's torn up so bad it's hard to get a good measure. The the sinew was about as thick as the horn and wood together but it varied more in thickness from the grip to the eye. It's hard to imagine that the wood added and structure to the bow. It's so flimsy. Do these numbers sound like they are in the ballpark? These are kind of averages so you can't get too much from them. It varies widely from the 1/3,1/3,1/3 but it was suggested that more sinew may be better for a beginner.
Yes, excess sinew will keep the bow from breaking. But if you have experience in sinew backing wood, i don't see a reason to overdo it. A 2-3mmmm thickness is enough. Originally those 42" short turkish bows had even only 50-60 grams of sinew (2mm layer).
I agree about the thinness of wood and horn, this is the problem with light bows. What can be done is made the bow really short and/or narrow. If one doesn't add as much reflex/strong kasan eye bend, he can put on more limb thickness and also keep the width less (and raise more thickness because of cutting width). This way the bow would still be 40-50 pound bow, but the limb would be more in proportion.
I have this kind of bows coming and i think its a clever way to have less gray hairs....
I don't believe in compression fractures. Horn needs to bend a ton more. It could have been a fracture somewhere that went down so fast, that there was no way to see what really happened. It happens. Thin, reflexed limbs are wobbly and delicate! Thicker, less reflexed limbs are not... While still being efficient. :)
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yeah, to me that looks like compression failure in two places among the horn
Where are the chrysals then?
not fracture, failure. didn't know how to explain it any other way. it looks like it happened in two places because it tapers off in the middle break. I feel like the middle break popped off between the two other horn.
if you look at the drawing and where the it breaks in the horn are, assuming that where the horn broke throughout the horn is the weakest spots, it looks like if it were put too much strain on, the middle break would pop off. and i also think its pretty curious that where it broke on the middle piece, that they both tapered to a point.
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I took a real close look at the remains. It was the cracked limb. If the failure followed the crack which I assume it would the crack must have been at an angle like the picture. That is starting to look like a delamination of the horn to me. If the crack was deep enough it's possible that the CA never reached the bottom of it. So maybe the crack was just waiting to bite me. Anyway that's as far a speculation will take me. It's just a WAG anyway.
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yeah, to me that looks like compression failure in two places among the horn
Where are the chrysals then?
not fracture, failure. didn't know how to explain it any other way. it looks like it happened in two places because it tapers off in the middle break. I feel like the middle break popped off between the two other horn.
How else would it fail? If not due to compression? :)
if you look at the drawing and where the it breaks in the horn are, assuming that where the horn broke throughout the horn is the weakest spots, it looks like if it were put too much strain on, the middle break would pop off. and i also think its pretty curious that where it broke on the middle piece, that they both tapered to a point.
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The most disappointing failure in doing most things is when you try it 2-3 times and failure is evident. Thats when I throw that project in the heap pile (brain and scrap bucket) and start another one. :}
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The most disappointing failure in doing most things is when you try it 2-3 times and failure is evident. Thats when I throw that project in the heap pile (brain and scrap bucket) and start another one. :}
All that stuff is just a state of mind. Free yourself! Failure is a fantastic things as it teaches you thinks far more effectively than easy successes. Of course we are brought up like this now through the media.
Embrace 'failure' because it isn't a 'failure' its one step closer to understanding.
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At the risk of sounding a little phylosophical....yep....There's got to be an unwavering passion for it.An all in attitude,but it can teach you to perservere through most any build learning along the way.
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I think I enjoyed each step, like when I was actually working on the bow, but I like to work on a project from start to finish. Working on it for a day or two and then hanging it up for months just didn't do it for me. I'm not a multi-tasker, I like to concentrate on a job until it's done. Still don't know if I'll do another. I'm doubting it right now.
I've still got two horn strips and all the jigs I made though. They keep staring at me.
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Come on, Don! Of what i heard and experienced you always can run into bad horn, bad luck, no control of this aspect. Not your fault. Next will be superbe! Its worth it! You can continously work on it ecxept of that month drying time. Lets do another one, like me, who stupidly put my first into hot sun, strung, till it flipped....and wrecked ;D ;D ;D ;D Sorry for your loss
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DC-i hope those other horns stare at you until they tempt you to give it another go. Your an awesome bowyer, and we are all rooting for you! :OK