Primitive Archer
Main Discussion Area => Horn Bows => Topic started by: Stick Bender on October 21, 2017, 06:51:41 am
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I have read BowEds thread on horn prep , read and reread Adams book ,watched a ton of utube and been studying composites on and off for a year now and still a little nervous about starting this project given the expense & rarity of good horn but figured I would post my question here instead of PM so as others in the same boat can learn ,I got these horns a while back they are flattened one side & now need to be thinned but at the thickest part they are 0.30 they also have some what I would describe as pitting on the surface so I need to get them thinned to find out how much width is available so my question is at this point being the thickest part is 0.30 should I try to heat straiten the horn for ease of flattening or thin them more ? I have thought about using double back heavy duty carpet tape and forcing them flat on a dead flat milled board in order to flatten more but there still just a bit strong for it ?
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Pitts
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That pithing on 1 side shown in the picture is just the natural grooves on the outside of the horn.A lot of that can be sanded away by crowning the horn on that side some.Then you will find how wide of horn you got too.Starting with 1 side or the inside flat to begin with.
The horn widths and thickness taper on my bows were 1 and 3/8" wide mostly.Narrower towards the tip end.Starting out as wide as possible is good.Tapered in thickness 1/32" every 6" of length on type of bow I made.Regular horn bows I don't think have as much thickness taper at least from the fades to midlimb because of working area and shorter length.
A person can slowly heat bend that horn then or before to a nice slow not too abrubt arch and flat with no twist.I use the heat gun very carefully and hold it in place to cool.Remember less thick less heat needed while using dry heat.Matching the pair in profile.It can be done steaming too with the way yours are thickness wise and clamping to the shape you want till cool.Some prefer to do it that way.This can all be done even with an 18" belt sander and a file.You want the thicker end towards the handle.It can get very thin out towards the tip too.
From there you can either groove the horn in a jig or glue it flat too.
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Thanks Bud you brought it together for me as usual Im hopping to pull 1 3/8 width on this one My maple stave is 61 in. trying to make one similar to your current hunting bow just a bit longer and a bit lighter draw , hey Ed how much reflex where you at before sinew after you took it off the form cured ?Right now I will take them down to 3/16 & see where Im at on width after straitening them a bit more!
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I gave it 8" and it came off the form with 5.5".
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Ok thanks Ed I need to make one of those forms like yours I believe yours was a Torges style form if I remember right, I found a padded adjustable leaver type clamp that can be screwed to a board and making some shims to put under the horn for straitening , if I can get this horn more strait & double back tape it to a flat board would any body see any problem running it threw a conveyer type drum sander ? I could at least get them closer with one side flat it would follow that thickness or maybe use hot glue to glue them down & then file to final thickness kinda like the way the guys that make lam bows do it ? Also need to pick up some rubber bands or old bicycle tubes but other then smooth on I have every thing else I need I think , Ed when you used your belt sander did you remove the stop so you could use the whole belt ? From my best guess at this point looks like I can get 16 in at 1 3/8 width or 17 1/2 at 1 1/4 width . Thinking 45-47 lb at 29 1/4 ! Might be able to split the width difference 1 5/16 won't know tell I get them down !
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Ritch....A 1 and 5/16" wide is enough.If you can cover at least 3/4er's of the width of the belly you should be ok.If you can get more length then that's better yet.If not the length sounds ok too.You might need to butt joint on the ends somewhere where it's not working too much to get more length.
I know a fella who used a drum sander thinning horn.It did work but I would'nt reccommend it really.I prefer to do it more slowly on the belt sander if that sounds good....lol.An overall crowning of the surface is what you should have too and a drum sander does'nt lend itself to that very well.All that should be done by hand with a fine file or sand paper.Getting a strong 1/8" thickness maybe 3/16" for at least a 6"to 8" length should do the job.Feathering out to 1/16" thick on the thin end towards the tip.
I should mention performance wise Marc has done closely these types of bows without horn but either way a pristene piece of wood should be used.A good compression strong wood should be used then if that narrow.Without horn the core should be wider.
For the type bow you want there I'll send you a diagram of dimensions in the mail tomorrow & you can call me anytime too.
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Ok thanks Ed & thanks for the specs but if you want to take a pic of them & send email that would work too save you the stamp & trouble if you want, well I really got to get them thinner to find out what I got I really want to keep it one horn per limb if I can on this first one but will butt if I have to , I was in the shop this morning figuring out how to make my quick release clamp horn straitening fixture this project will keep me out of trouble for the winter...lol still have my croaker bladder glue to make too , I will use the belt sander then I think I'm taking the material stop off it so I can use the whole surface !
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Try and get rid of those cracks on the outer surface. They can run deep and sometimes you can't tell until you start working them.
No problem using the drum sander, it is a very accurate and dependable method. I actually stick my horn to a thick piece of ply with hide glue, do the thinning and tapering. Then whilst still stuck to the board I establish the centreline and do the grooving. It was one of the best ideas I ever had! You can also use a taper sled to establish the taper on the horn.
Don't worry about getting the longest possible set of horns, go for wider rather than longer BUT you really should get rid of all natural grooving on the outer surface before doing anything else, don't trust that you will be able to remove it all once glued to the core. All it takes is one hidden crack....
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Ok thanks Mike that's a good idea whith the hide glue & water salable too ,easy to get off , I'm going to make up some ply feed tables for them after straitening at least get them close the taper jig is a good idea to get close, with needing to crown them I will do the final dimensioning by hand, I was going to pick up a commercial taper lam as a pateren for the taper matching Eds specs thanks for the input !
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I sand all the ridges/cracks away to get the flat outside - BEFORE the cuting of the horn .... it is easier to prepare the strips afterwards
Then I sand them on the belt to get them almost the same thickens (+- 1mm) ,
THEN cut them to the same width and length...
Then heat bend them to be almost flat...
And finally attach them to flat surface and scrap them with razor blade to get them the same thicness (on the same length positions - they are tapered from 5.5mm to 3mm at the tip - depends from horn)
Doing the final check with caliper ruler - 0,1mm !
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Use a leather or wooden spacer with the clamp, you don't want marks or damage on the horn.
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Thanks Fellas I also have these 2 sets that I could use the shorter ones I could for sure get 17 in. The longer ones probably 21 in at 1 3/8 in they would be more work at this point but wonder in terms of going into the fades like BowEds bow it would give me more working limb ? But would rather put the work in now then run into issues down the line ?
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The fades part that's glued down is heat bent a little to conform to better to eleviate the risk of cracking then while being clamped and thin enough around 1/8" thick prior to glueing and clamping.That's all done with a dry run clamping prior to actual glue up on the type of bow I made.Your longer horns there should do the job.
Preperation of thickness mentioned is a superb way of doing it too.
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On straitening these horns it was mentioned some use steam with steam only being 212 Deg F I'm wondering when I use dry heat to bend these slightly with the fixture if I apply dry heat at about the same temp will that work ? I'm just trying to use as minimal heat as possible on these horns and just bent enough to glue to the feed table ?
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You can use dry heat - korean bowyers do it - but cooking them will ensure that you don't go over 100°C. Cooking them for max 10mins and then clamping them for an hour or so is enough. The 17" horns should be good for a hungarian bow, the other ones are comfortably fine for a turkish bow.
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Thanks Bjoern the type of bow that I'm attempting is like Eds latest composite prodigy thread , maybe I will steam cook them and straiten I have seen so many articles on bending horn from bolling to dry heat to open flame I think Adam Korpowicz preferred bolling ,at this point I don't need them perfectly strait but strait enough to hide glue to a board , I'm going to continue with this set to iron out every thing and if I don't have enough length I will work the others or adjust the design !
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Steam is the way to go if you aren't sure.
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Thanks Ed I got your spec sheet in the mail tonight really more of detailed journal of your work you keep meteculious records there Bud I appreciate it hope to get some work in on it when back from hunting Saturday unless I poke one , thanks Mike maybe I will try steam for the initial bending with them being thick at this point might be the better option !
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I made up some simple tooling for straitening & prepping the horn strips dug a 4 x 4 out of the wood pile & milled it dead flat added a quick release clamp ,made some assorted shims and used dry heat with a infrared thermometer & didn't let the heat get above 220 Deg F, put shims at the areas that needed straitening it worked great I also found some dead flat Ply wood and made feed tables for the drum sander I decided to use the method I have used for years making furniture Lams I used commercial grade fiber glass reinforced carpet tape to bond the horn to the feed tables it is a very strong bond it will need heat to release them next I will start taking them down in thickness with 80 grit sand paper on the drum !
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Straitning jig
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After
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Feed tables
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Well I really wasn't trying to turn the thread into a build a long ,just kinda worked out like it ,sense this was the first time doing it thought I would post how I did ,there are many ways of prepping horn Ed did his by belt sander and files ,I have so little bow time that I use what's avalible to me my way takes far less skil then how Ed did it here is the equipment I used I ended up at a smidge below 3/16 to get under the ridges but won't know exactly what I have tell I remove from the feed tables I used 80 grit and a medium feed speed the dust collector helped a lot keeping the burnt hair smell out of the house I guided each peace at a skew both directions & reverse to keep the horn dead flat & even ,the whole feed processe took about 1 1/2 hours the shorter horn strip ended up at only 17 1/2 in. Length , so now that I understand the process from hands on I think I will processe the longer ones but key in this system is to make sure one side is dead flat & as parallel as possible to start with !
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Feeding
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End result !
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I'm a little anxious to see how it comes off that carpet tape. That stuff is pretty tough.
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No problem Don I just heat up the fade end a bit and put a knife blade under it and a little pressure as you go , yes your right this FG reinforced tape is brutally strong stuff there is a little residue left on the horn but will clean right up great stuff used it for all kinds of stuff !
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Glad to see that. Carry on!
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After taking them off the feed tables ended up at a little under 3 1/2 mm,9/64 so Im ok on thickness the shortest usable length is 17 in. ,both horns are with in 1/1000 on thickness of each other the 9/64 being the thinest the plan calls for 1/8 thickness so Im good on thickness ! But I ether need to prep another horn for a butt exstention or prep other horns , I think Im going for the 2 1/2 in.butt exstention and save the longer horns for another bow !
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Nice and flat for sure. Looking good. (-P
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Nice work that drum sander does.Wish I had one myself.My friend Grant does an hour away.Horns' looking good bud.A butt joint 2.5" from the tip should work ok.The joint should be dead nuts square with each other and be hardly noticeable.No wrap should be needed either IMHO.It should be hardly working at that area with your length limbs and be very thin.1/16" thin or less really.You can wrap and match it on the other for looks for self security confidence reasons though.
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I will make sure every thing is square when I get there I'm going to leave the butt peace long until I get the joint perfect ,yes the drum sander is a real time saver for making all kinds of lams, if I was going to use the belt sander I was going to take the flat board and put 2 aluminum 3/16 flat stock peaces on ether side of the horn like rails put in place with the carpet tape and put painters tape on top of the flat stock and run that upside down on the belt sander and when the sand paper started taking off the tape it would be close to the 3/16 or better kinda a thickness gauge just a thought for some body that has a belt sander or you could develope some talent & due like Ed did...lol Aarin don't know if there's much to watch just kind of feeling my way threw it here ,Next I'm going to make up a templet of the limb dimentions that Ed sent and lay the horn out I'm going to wait tell I make the core for final cuts on the horn just in case there's any changes !
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One thing I'm learning about prepping water buffalow horn is you get far less usable horn then you think in the pic those sets range from 50-75 cm & none of them will give me the 19 1/2 in. I need for this long bow type composite with out butt jointing but would be perfect for Magyar or Turk bow but the Gemsbok horn has a lot of length compared to the water Buffalo horn & would be well suited for the long bow type composite , I'm going to use butt jointed water Buffolow horn on this build , but for any body thinking about building one Gemsbok horn would be a cheaper solution too !
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Bear in mind that you don't need horns that long anyway. You caould safely end the horns a few inches earlier and simply shape the core to stop any bending in the outer limbs.
Virtually everybodies first composite (after making wood bows) is understrained. 19 inches of horn would make a bow that is capable of being drawn way past 30 inches. There is no need to play it safe with these materials! Also more bend near the handle is a good thing, the limbs are thicker there and have a faster return speed than the thinner outer limbs. Bending closer to the handle (without outer limb bend) gives the tip a longer return path. Longer non bending outer limbs can be lighter (narrower) than bending outer limbs.
Gemsbok is ok horn but you can run into problems with it being too thin after flattening and you need to heat them quite a bit to flatten the concavity across the width. Which is a shame! Just remember you do not need all that length unless making a Manchu bow and have a 36 inch drawlength haha!
After prepping these horns can you see why the Turks used concave/convex horn/cores? :)
A useful ratio is bow length to potential drawlength. bow length of 48" / 1.6 = 30 inch draw.
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Yep your right after working with these horns you see why the elders did what they did concave/convex etc & also see why the Magyar bows are popular with the shorter horn I'm attempting a longer one like Ed's bow on this one @ 30 in draw maple core !
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Im prepping the exstention horn this morning and was wondering for you guys that have done this before , how many times can you reheat horn with dry heat before making it brittle I make sure Im not exceeding 209 Deg F ? Im not trying to get it perfectly flat just enough to run on the belt sander to get one surface flat ?
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Im just trying to pass a long what Im doing as I stumble my way threw the process I always liked it when I was trying to learn something and somebody would post pics so my way might not be the right way, but on a raw horn strip where one side is concave I used the belt sander and fingers to feel the flatness on this hornstrip I dont have a lot of thickness so Im being real carefull not to get to thin but as you can see by the second pic after its off the belt sander even though its hard to feel ,the horn is still a little concave so I did the final flat side finish with a sharp scraper Im glad that I made the quick release jig it really speeds things up because you can quickly change positions for scrapping & eye balling your peace ,this horn strip was just a spare any way because of the laterale bend on the end so it was a good canadate for the exstention and it was also thin !
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Still concave
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Flat side ready for the drum sander
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I ended up finishing all horn peaces I need ,still need to dimension the width & tapper but need to figure out how to make a tapper sled for the drum sander , I decrowned a hard maple air dried stave earlier but need to make up some 1/8 ply templets from the specs Ed sent and the list goes on I need to processe about 1400 grains of elk sinew,make yellow croaker bladder glue ,make a reflex form , a bending call to match Ed's for the hooks & hit the bike shop for some old iner tubes Etc, If any body has any suggestions please let me know !
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Maple core stave
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Don't use innertubes. They stop the water escaping and don't have the clamping power when they touch the hot core and horn. Look up the rope and wedge method. Wrapping with the rope and binding tool. Or clamps and a pressure strip.
You can make a taper sled by getting 2 pieces of dead straight wood, figure out the taper you need and then insert a spacer of the desired size inbetween the two pieces of wood, put the whole shebang up against your fence and run through the bandsaw. Simple :) Or contact a galls bow builder like Big Jims bow company and ask them to send you some precut/ground tapers. The will ask for the taper rate in thousandths per running inch.
Consider what I said earlier about butt joints/horn length/drawlength....
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You know Mike I have been fixated with using the drum sander that I never thought about the band saw tapper sled, I kind of wanted to make the sanding sled for future lam type bows to, on this bow Im using smooth on ,hence the rubber bands , also a updated using the doubble back tape the first time I used it a older roll It had worked great I bought a new improved roll and it was much sticker to get off no problem getting it off just a pain to get all the addhesive off , used soap & water but there is still some residue left I will have to figure out how to clean them before glue up or rescrape they still are thicker then finished dimension !
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looking great,, (-P
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Thanks Brad this one is a new experience for me it's a lot of fun so far !
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Acetone.
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Thanks for adding that Mike I was going to use it but was afraid it would dry the horn out I have a 0.005 actionboo tapper sled comming from one of the guys on another site figured I would use it as a pattern it was cheaper then buying the materials to make it !
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I didn't have a lot of time this morning but got a chance to lay out and make a limb templet from 1/8 in. Pattern ply wood for laying out the horn , you really get a concept of how short and narrow one of these bows are when you lay it out , also got a friend from another site Kenny to make me a 0.005 tapper sled for the horn , I'm going to double check all the measurements & start laying out the core next & build a Dean Torges style form for glue up !
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Tapper sled
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how does a taper sled work,,??
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Brad it's basically a platform bed that's tapered like a bow limb that drops Aprox. 1/32 every 6 in. the horn is put on it basically as a parallel lam and feed thru the drum sander so that tapper is ground into the horn and the core is done by hand with the same tapper so when it's glued up it has a tapper that drops Aprox 1/16 every 6 in. the only problem with using it for horn is with the slight bow in the horn the pressure rollers on the drum sander won't hold the horn flat enough for a precession grind so I will have to secure it with double back tape it's really important on these bows that it's done right 90% of the tiller is done before the bow is strung ! Also the tapper sled is wide enough that both horns can be done at the same time to get exact twins !
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wow,, (SH)
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Brad these bows can be done all by hand to ,so it's not that complicated it takes far less talent to use the machine so don't let that scar you if your thinking of making one )W(
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Got a chance to work the core a bit today every thing that I have studied over the last year says that the core and the core selection is the most critical part of making a composite and realy good sugar maple is hard to find but I got lucky and found this stave I decrowned it last year and it's been inside at 50% RH or lower for a year, at the apex of the crown perfect strait grain lines up for the whole length got lucky ! This is where making the limb templet realy helped with exact dimensions I laid out the center line & handle ,fade locations put the templet on the center line traced it rechecked the numbers and done with front view layout as long as I maintain the center line I can check or redraw the layout any time I left the lever fades & leavers wide so I can lay out the tappers and bend the hooks I cut the profile close on the band saw and snuck them in closer whith the osolating sander (thanks Ed for talking me into geting it ) I also changed the bow lay out from Ed's plains his was 58 TTT I'm extending my leavers out 2 more inches per limb for 62 TTT with the hopes of a lighter 45-47 lb draw weight next is laying out the side view and tappers !
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Center
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Templet
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More
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More
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More
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More
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Don't do anymore narrowing. You may need the width later. Gluing the horn can induce twists. The thick and wide core acts like its own form.
You should get the core to the side profile you want. Glue the horn along a centreline. Then reduce the core.
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Gotcha Mike makes sense especially out on the outer 1/3 , thanks for stopping in doesn't seem to be a lot of interest on this side for composites !
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Personally I think 62" is too long. You are not taking advantage of the tension and compression properties of a horn and sinew composite.
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Yes that's good advice from Mike and see his point.I was always able to get the exact proper thickness on the core before glueing the horn on all of mine and it worked fine too.Then applying the proper amount of sinew to get to the poundage I needed evenly and crowned nicely too with 3 applications of sinew within a 2 week span of time.Using Pat M's method of shaping it and smoothing it after final application of sinew just with those 1" to 1.5" wide cotton strip wraps.Some light sanding will be required yet but it should end up nice and smooth and to the thickness taper you need.
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Aaron...Ya I know what you mean there.He should only have sinew on 44 to 46 inches of the bow though including the 8" handle.He'll be drawing it to 30" I presume which the bow should handle that pretty easily yet too.
This all depends kinda on how much reflex Ritch induces into the bow.I know he's tentative about it but it's up to him.It's a first time type bow for him having not tillered a bow with a whole lot of reflex but 10 t 12 inches should be doable easily.
I've always used to had to C clamp the bow to the tlllering tree to tiller it but since I made that peg board which I guess he might it should'nt be a problem getting it to brace and then tillering on the tillering tree.
I'l let Ritch comment himself on his intentions.
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Aaron thanks for the comments by most composite standards I agree but there is a couple caveats in this case , this bow is strickly a hunting type bow for legal reason I have to go to the field unstrung and string primitive type stringer in the blind or stand so thats a huge consideration , but by Eds reports with this design being similar should be able to get 180-190 Fps 500 grain arrow Im not looking for a rocket per say on this one just a very durable reliable hunting stable bow Im in the shop now and after Ed's and Mikes and what you said Arron sugestions , Im shortening the working limb & TTT so no need for butt joint/length so far I figure 15 1/4 horn/limb 0.005 tapper core/limb & 57-60 TTT just trying to calculate draw weight with the mods still trying for 45-50 lb , Aaron this is my first composite & Im trying to take baby steps along the way but I dont want a dog ether once I get the system down I will make a more effecent composite !
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It really is looking good so far Ritch. Have you seen how the Koreans string their bows, sitting cross legged with no tools? With a light weight bow like your are aiming for, using this technique you should be able to string your bow in the field with a little practice.
I too am working on my first horn sinew composite right now, so I understand what you mean, crawl before your walk....
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Also I plan on shooting heavy arrows 600-650 grain out of this bow so Im not looking at getting Eds numbers but here is the lay out with 62 TTT & 16 1/4 horn Im still leaning towards the longer 62 in. & butt jointing the exstention and I might prep some more horn and see if I can get some longer slats ,well see Im in no hurry just trying to get it right for what Im trying to do these bows are pretty work intensive for the time I have to put in so weighing my options !
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Your plan on using matching grooves, or no?
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Non matching how about you ? And Im using smooth on ,you ? I think Ed if I remember right didnt use any groving at all with smooth on Im probably going to just ruff up the surfaces with 50 grit like the glass guys do , I think Adam mentioned in his book that matching grooves are a moderen addaption he never found any historical evedence for it , I think down the line I would like to try the magyar style like you, they seem to be Idealy suited for the WB horn , Hey Aaron did you end up getting yellow croaker bladders for glue ? Im using elk or moose sinew on this one I havent got around to making the bladder glue yet ! also are you tappering your horn ?
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Matching grooves, with fish bladder glue and rawhide glue. You are correct, there is no evidence of matching grooves being used before 1930.
I ended up getting some sturgeon bladders from Bulgaria, I can give you a contact if you want it. Croaker bladders would work probably just a well at half the cost of the sturgeon, but they say sturgeon is the best of the best when it comes to air bladder glue. I used it for peace of mind.
And yes, I tapered my horn from 5mm at the grip to 4.5mm at the base of the siyahs. 15" long horn, 48-49" ttt bow
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Ok I just remembered you where asking a while back on the yellow croaker bladders I'm just going to use that and high grade hide glue combo on the sinew I think if I were doing traditional glue up like you on the horn I would look to the sturgeon glue ,to that bow sounds nice ,what weight 65-70 lb there just guessing from your horn ? Look forward to you posting , I'm letting the sinew cure 16-18 weeks when I get there good luck there !
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Good guess, I'm hoping for anywhere from 50-70# if it makes it at all
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Any good quality glue is good enough. The main reason for using croaker glue is a longer 'open' time before gelling. Hide glue gels too fast for me but then it is never above 20 degs in my workshop, now I have a hard time getting it above 12 - 14 degs so the slower gelling glues are needed. Like I said don't worry about the strength of the bond with any collagen glue.
Bow length divided by 1.5 will give a drawlength. 62/1.5 = 41.3 inches.....:) I hear what you are saying about length/playing it safe etc honestly there is no need to play safe by under stressing the materials...they can take it and more. Sinew/wood/horn is a truly amazing combo after working with wood and all its limitations ;) You are highly unlikely to break a hornbow that is well made. Making it well made is the hard bit haha!
Put your sinew on in 1 mm thick layers, 2 weeks drying inbetween layers, sand with 80 grit inbetween layers and you can safely forgo the lengthy waiting times. I totally agree that if you put on thick layers you do need to wait - thickness in mm squared - weeks. With the 1mm layers it really doesn't matter.
I would advise against wrapping a composites sinew layer, it is essential that there is enough glue in the matrix if not it could go bang...wrapping was not used on the old bows and they seem to be doing fine with beautiful aligned and flat sinew. It is all technique :) The Korean method of sinewing has a lot going for it. Excess weight is much better removed from the non bending sections.
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With the croaker glue I'm using it like you said to prolong gel time I do most of my work in the winter months ,making these bows can be a daunting task if you never did one but they are a heck of a lot of fun to make ,but with all due respect to all here why is Ed's bows capable of the speeds that he is getting I know he goes out of his way to publish honest real speeds , when this type of composite long bow goes against a lot of doctrine ? I'm just trying to open a honest topic about it ,not be a smart ass but with this type of design and the thinner horn longer working limb strategically placed sinew & mass it seems to work ,certainly above self bow and some glass bow performance I know from my meger exsperience there is always a trade off with varying designs , Mike I know you have made a heck of a lot of bows so your input would be appreciated , the interesting thing about this type of long bow composite is there is actually some historical reference to it found in Russia, I'm just trying to wrap my brain around the concepts I know Adam talked about efficientcie of the different designs and why shorter bows are more efficient I don't know maybe the bow would be faster shorter with less working limb but wouldn't I give up field user friendliness & stability ?
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Well this is where Im ending the week end bow work needs some time to think out the design , but here would be the ruff layout at 62TTT that would give me aprox including the 2 3/4 static fades 12 inches of static it doesent seem ballanced to me when I look at it the other 2 pics are a 62TTT & 58 TTT static comparison the block is the limb cut off for the shorter both limbs would have around 17 in. Working horn if you subtract the static fades that includes the handle fades, thanks all for the input Im going to give it some thought for a few days.
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62 TTT
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58 TTT
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Mike I will recheck the lay out the stave was sawn from the supplier it did not follow the grain so I put the center line accross the apex of the crown some of that is optical with the phone camera But I will recheck it I'm plaing on steaming the recurves in at the tips and inducing limb reflex at the time of horn glue up and after sinew hoping for a total of 10 in. Total reflex I'm sticking to the original plan of 58 TTT I decided , I might thin the horn slightly and reduce sinew to 1000 grain insted of 1100 to slightly reduce draw weight instead of lengthening the limbs or deal with the exstra draw weight
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Looks like a great project, and I am thoroughly enjoying the build along, thanks for putting it up. In my humble opinion, I would get the core bent to shape before proceeding with any more layout, as the centerline might change after bending. Then I would draw the centerline as Mike suggested, on a flat surface with a spacer block, and do the layout off that. Also I would bend it to shape as thick as the thickest part of the final bow, this will help minimize twist during the horn glue up.
I wouldn't shy away from going for 58" ttt if stability is the main concern. I've naver made a horn bow longer than 48" ntn, and I am comfortable stringing most of my bows in the field and dragging them through the woods. Once they are tillered and tamed, their behavior becomes quite predictable (unless, perhaps, they are left unused for months, then they may begin to revert to their old ways). I almost always use the korean stringing methods, both sitting and standing variations, the standing method is easier with longer bows.
I look forward to seeing your progress!
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Thanks for joining in here Dave first off I should call it a bumble along never having done it Before I thought it might help others on the side lines that never did it to see all the trials and tribulations it takes ,on this design the only bending on the core is the recurves the remainder of the the core/horn reflex is put on at horn glue up in a perry type fashion and the rest from sinew cure I was planning after I recheck the lay out is to start thinning the stave to the static thickness dimension and bend the hooks prior to thickness tapering the limbs I was leaving the last third wide tell the hooks are done . I'm basically trying replicate for the most part BowEds prodigy bow !
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Ok Mike thanks the stave is flattened I meant I followed the crown on the end view of the flat back the grain under the flat back I will hopefully get some time next week end to process the core , going to be busy with work over the next couple of weeks !
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Perry reflexing is probably a poor choice of words inducing this reflex.Not the same as reverse bracing.I've made a bunch of these bows.At least 6 without any failure.4 different woods also.Tips are flipped on them all.Some more than others.Reflex induced at stages letting sinew gel and even cure a few days between applications.The sinew being put on crowned takes care of any poisene effect the back may have during full draw.Getting the most out of the sinew so to speak.No delamination problems.Types of applications explained properly clear up misunderstandings.Used the back for the sinew too.Horn on the inside of core too.No problems.Pre tapered core and horn glued together with no twisting problems with core just braced and tips aligned before horn is added.
This will be low stressed intermediate type bow between long and short to get 2 things done I gather from Ritch.More stability and accuracy from the added length compared to a turkish horn and lots of kept reflex with light set back outer tips for speed with a very much lowered mass weight type bow yet way under the reccommended mass weight on an all wood bow of this profile.The reason for it's outstanding fps showings besides design and tillering.I still would'nt call it a holmgaard really either.Some people I guess can shoot really short bows accurately maybe at the range but hunting is a completely different ball game.You are'nt shooting in any comfortable position as at a range and sometimes there is something about a moving wild animal that puts their mind set into a shaky in accurate mess.I guess practicing is the key here but I can't seem to get the hang of it.Too fidgity.Longer bows have always been more accurate and dependable in that department for hunting for me speaking from lots of experience.Guess it's a personal thing.
Anyway all I can say is that not one of the bows I've made in this way has failed from a construction type flaw and I know that sometimes through inquiring we all hear something we don't want to hear as far as advice.I wish sometimes people would put way all these hard line scare tactics to new bow makers without full explanations for their statements.I realize there are things to be aware of but stating that something wo'nt work when it does is incorrect.Could be lack of info and understanding here also.
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Yes it was a poor choice of words on my part I meant the horn is applied and secured with rubber band type clamp,Smooth on and then put on the form to induce the reflex during cure the form will 8 in reflexed In hopes of keeping 5-6 in. Of core/horn reflex prior to sinew this style bow can be confusing in it's idenity in the sense it sort of a Asian/Amercan Indian/moderen fusion hunting type bow for lack of better words...lol The details are in Ed's Prodigy thread below I'm just trying to replicate it's construction more or less , all the different thoughts are appreciated as I would like to make a Magyar bow in the future with more traditional construction !
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Here is a bow of similar design found in the Ural mountains of Russia #3 note how the belly core is flat and the horn rounded the others are American Indian west region bows not a lot is known about the Ural bow other then it was comon in the area !
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Your right Mike it's hard to make all your points and come accross on the right note, I have learned every thing about making bows threw correspondence & reading and school of hard knocks...lol so interpreting thoughts from people via words is tuff or exspressing what your trying to accomplish doesent always come accross right , and there is no dought the old ways are superior and more work intensive I know that , That's why I choose this design not trying to short cut or I'm not a lazy person I just have very little time for bows so any thing I can do to simplifie or speed my proseses I do whith the caveat not effecting performance for the design that's why I choose this design over a more traditional one I was originaly going to make a form, fire hose system to put the horn on & hot box like a glass bow but decided not to,all though bet it would work I don't exspect my bow will be perfect on my first one fore sure I'm just trying to get a solid hunting bow threw non traditional methods using mostly natural material , I know Adam used smooth on , on some bows to ! But a lot is learned from the old ways & the old material and I'm going to try one like that in the future.
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Mike...So to talk sensibly about the dynamics of limb strain you don't think by crowning the sinew that it helps with the poison effect and make the sinew more efficient?Soild thinking is behind that too and stated in Adams' book.I totally realize Adam Karpowicz investigated and worked out more things about cultural horn bows than I ever have or will.
The bow Ritch wants to make the way he wants to there will hold up IMHO.Speaking within the context of this design.If not every sinewed self bow would be delaminating and blowing apart.There is'nt all that much strain on that design.With your shorter more extremely tight bending type cultural horn bow I can definitely see the reasons why.From what I've read it's for steam bending reasons the exchange of back to belly orientation use.
A regular cultural type horn bow is a completely different animal then what Ritch is trying to make.Context crossing of construction statements should'nt be confused here.To me it's all about the ending thickness for draw poundage no matter what way it is done.
I can definitely see why starting out with a thicker core before rope wrapping the horn onto the core will reduce most if any twisting occuring on turkish horn bows.Then reducing core thickness to accept thickness of sinew to get final thoughtof thickness.This is not the case here with the bow that Ritch is constructing.