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Main Discussion Area => Bows => Topic started by: globalmark on April 15, 2018, 12:58:54 pm

Title: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: globalmark on April 15, 2018, 12:58:54 pm
Hi Guys

i hope someone can help – I have made a couple Bows – one with Bowyer “Chris Boyton” here in the UK , but would like to Make a reflex .deflex recurve or longbow (whatever you call them) – I am also a cabinet maker so have no problem with making forms , Glue ups or anything like that  and have started making the form .

However I dont want to use Glass (bo-flex) this time but have bought some 2.4m lengths of bamboo slats 45mm wide from a bamboo supplier who sees to Bowyers – so good looking stuff needs tiny bit flattening but pretty close already .

I need a long bow as 6’3″ and draw like 32″ when measured my arms – so came up i needed a 70-72” bow one long bow i have is 80+ lbs I cannot draw all the way , my other 50+lbs i can draw just about (had dislocated shoulder before) , and friends recurve bow easy to draw – I enjoy making rather then using so Dont care about draw strength , I DONT hunt so just a decent strength bow 40-50lbs maybe but whatever works ok .

But as only made long bow types before have no idea of the lamination thickness – how much taper etc

So can anyone help just recommendations on how many laminations , thickness of laminations , what taper to put in them and which ones – I was thinking maybe either “all Bamboo – with timber handle” , or “bamboo belly and Bamboo back” with core or timber ? or other suggestions ?

SO width’s , thickness total at handle and tips , what recommend etc .

Any help would be great

Thanks Mark

Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: Stick Bender on April 15, 2018, 01:36:05 pm
Hi Marc I made a simple bamboo backed hickory bow last year 68 TTT 48 lb @ 31 in  with a 14 in. Riser front profile was parallel 1 5/16  for the first 14 in out of the fades then direct tapper to 3/8 at the tips it was a single core ,taper just under 3/8 at the fade  to about 5/16 at the tips Aprox. (0.005)  I glued in a little over 2 in. Of reflex on the form it keep  about half of that  it's a very soft shooter and constantly does 173 fps with 520 grain arrow
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: globalmark on April 15, 2018, 05:34:24 pm
Hi Stickbender

Thanks so Much for the reply
if its ok couple questions

Do you have 2 layers or 3 layers (lams) as mention the bamboo back and core but nothing about the belly ??

What was the Thickness of the Bamboo Back Lamination ?? and is this straight or tapered - I presume the measurements you mentioned here (from profile) was the width of the bamboo Back NOT the thickness ?
you also mention the Core taper 3/8 to 5/16 at the tip (this is dimension of JUST this core Lamination or overall thickness of the bow)

Thanks Mark
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: PatM on April 15, 2018, 05:40:23 pm
Using deflex and reflex you actually don't need to make a bow that long.

 There's only a couple of guys on here who make lam bows in glass style (without glass) where your tillering options are more limited to tapers done before gluing up.
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: globalmark on April 16, 2018, 03:02:54 am
Hi Patm

Thanks for the Reply
Yes I also thought was Long but all the Information I could find on a recurve Bow length related to my Draw length which I measured and I am 6'3" tall and think my Draw was 30" + so everything I read said 70" bow , but maybe i should shorten before build to 68-70" ?? i really dont know here myself ..

Yes I understood that tillering was done before final glue up or tiny bit on the side -
Does anyone know if i sanded the Nodes off the Bamboo belly to tiller (as some bows have these sanded off i have seen) - would that make the bow weak or cause a problem ??  to aid in Tillering ?
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: Ryan Jacob on April 16, 2018, 06:09:22 am
Depends, how deep did you sand?, a picture might help illustrate the situation.
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: Stick Bender on April 16, 2018, 06:35:46 am
Hi Mark , name here is Ritchie but my bamboo was just a hair shy of 1/8 and slightly thinner towards the tips the bow posted is just a simple long bow that you mentioned in your OP the belly hickory is single lam as posted above ,I  find keeping my bows longer at the 31 in draw helps hold the reflex better , I might suggest getting a hold of a copy of Dean Torges Hunting the Bamboo bow excelent DVD he covers soup to nuts & forms on these style bows there is a couple of guys around here that have made quite a few R/D bows in that style , Bayu Ben & BowEd come to mind , that simple long bow posted is one of the smoothest shooting natural material bows that I have made and shoots a near 11gpp arrow well !
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: Stick Bender on April 16, 2018, 06:49:30 am
Also ether style mentioned can be made on a simple 2x4 form
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: globalmark on April 16, 2018, 07:51:21 am
Hi Guys
thanks for replies

Ryan - nothing Built yet - just gathering Materials and dimensions first so can get prepared to Build - started the form is all so Far and hand planed little of the bamboo but lots meat left on that to plane as necessary - picture attached I think but nothing to show yet ..

Ritchie - thanks for that Info will see if can find that video - or info , I have googled every thing i can find and watched many youtube videos etc .
          - Have already Made a form and used them many times when making other things - so might use that this time and try your method next time - do they work better then a form or just not necessary ?

Thanks Mark
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: Stick Bender on April 16, 2018, 01:38:38 pm
Marc I'm no expert on these bows I can only share what I have done or experienced but the 2x4 form is a really versatile form the pillars can be changed for different levels of reflex or deflex , the only bows that I have repeatable made are leaver self bows , I like to experiment with different  designs and the 2x4 form is very adaptable , also I found it helpful to make a templet of my limb lay out for future bows or modification , also these bow are not automatically tillered there is always some thing to tweak, but like a friend of mine says the devil is in the details , the more time you spend in preparation before glue up the closer your going to be !
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: Jesse on April 16, 2018, 02:57:20 pm
A lot depends on what type of wood do you use for the belly side. As the general guide 1 1/4 to 1 1/2 wide tapering to 3/8 at the tips to start. The thickness taper should be about . 0 0 4 per inch. If you are planning on a bamboo belly with nodes I would glue up the bamboo back and your tapered cores first. Tiller until it looks good and it's about 20 lb underweight keeping the belly flat. Then add the bamboo belly because you can't do much tillering without going through the nodes.
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: Jesse on April 16, 2018, 03:34:35 pm
I'll go a little bit further. I recommend using ipe , Osage, or hickory as a belly wood. If you use ipe 31.75 mm wide is fine. Make a tri lam. Natural bamboo with raised nodes on the back. Use your bamboo as the center  core making it. 4mm thick with a .05mm per 25.4mm taper . make your ipe belly 6mm thick with a .05mm taper for a total taper of .10mm per 25.4mm. Skip the bamboo belly. This should give you roughly a 60lb bow at 66" ntn. Tiller to your desired weight of 50lbs. Use an 18 to 20" power lam between the bamboo back and the core. Make it 6mm thick tapering to nothing. Make your handle 11 " long including fades. Hope this helps :D
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: Bayou Ben on April 16, 2018, 03:56:30 pm
I agree with Jesse.  If you're dead set on using bamboo for the belly it can be done but you will be limited by how much you can tiller, and there's not that many out there doing it, so you would be on your own some. 
For your 1st tri lam I would suggest using ipe or osage on the belly.  You can use a bunch of different core woods. Some good ones: walnut, maple, red elm, ground down bamboo, hickory.  You already have the best backing IMO, natural bamboo. 
Another option would be a bamboo backed board bow.  This would be my recommendation on your 1st try.  It's just a lot less complicated.
Let us know which way you are leaning.  There's guys here that can help you in any case.
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: globalmark on April 16, 2018, 05:09:20 pm
Hi Guys

Thanks so much with all the help
I actually went to local timber yard today but had nothing i could use really as sold only slabs - I am in the UK so need a specialist exotic hardwood supplier so cheapest i can find would be over $100 just for small plank of Hickory ..no IPE or Osage here that can find ..
I already have the Bamboo Slats - cost like $5 us each - and can put core in or oak, maybe have ash , or elm - or can use more bamboo ..

I am not bothered so much By how many pounds the bow is as enjoy making and here in UK cannot Hunt anyway so will only shoot few Hay bales - so as long as 35-50Lbs i dont mind ..

Currently was thinking Bamboo back - hardwood core , Power lams as some one suggested and Bamboo belly or even complete bamboo laminated bow with hardwood riser .. but really have no idea here .
any more thought appreciated , and what parts should be tapered ?

cheers Mark

P.s saw this in bamboo shop had for demo see pics was a idea all bamboo-
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: PatM on April 16, 2018, 06:15:41 pm
 leonwood could probably advise. Check out his boo belly retrofitted bow on this thread.
 http://www.primitivearcher.com/smf/index.php/topic,63176.msg886936.html#msg886936
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: Springbuck on April 16, 2018, 11:01:44 pm
Also not an expert, and it's been a long time, but I learned a few things.

First, flatten the glue surfsce of your belly bamboo, but leave it thicker than finished thickness. Do your toasting/tempering next.  What happens here is that the rind surface shrinks and actually flattens somewhat laterally (removes some of the crown) as a reaction to the heat.   The flat surface you prepared to glue will bulge slightly in response and must be flattened again prior to glue-up.

Yes, you can sand the nodes flatter on the belly side, but don't go crazy.   If you mill the entire surface very st, you are violating some fibers rather steeply.

I went with a consistent thickness back and belly (as near as obtainable with bamboo), of 1/8 on the back and 3/16" on the belly.  I tapered a thin core of vertical bamboo flooring from about 3/16" middle to less than 1/8".   I think I added reverse wedges at the tip, but very thin. 

The handle was two tapered blocks glued together and sandwiched between the rest.  The backing on one side, core and belly on the other.  I glued core to handle, belly to core, and backing to handle and core in stages, sanding transitions each time.

I did not force either bow into a deflex form, but the shape of the handle filler deflexed it slightly, and I reflexed the tips about 2-1/2".   I left the whole thing full width,  just shy of 2" wide, and relied on clamps and shims.   I planned on doing all tillering from the sides.

These bows were very stiff, and had to be narrowed to less than 1-1/2"   They took enough set near the handle that they became R/D bows, but the tips stayed ahead of the handles.

Hope it helps.
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: leonwood on April 17, 2018, 05:58:14 am
Thanks Pat, missed this post somehow!

You can follow Springbucks advice above and that will work for sure but is probably a little harder because once glued up there is not much wiggle room to change your draw weight or tiller.

This is the way I did it a couple of times:
First make a really flat back lamination of bamboo.
Then pick a core lam, you mentioned ash or oak and they will both work fine.
You can leave your core relatively thick at this point but you can also pre-taper it a bit if you like. Mine are usually about 8 mm at the middle tapering to 5 mm at the tips. I don't really measure a lot as I build all my bows by feeling.
Glue the core and the back together with a little deflex and reflex. I do this with just a few blocks under the tips, midlimb and the handle section.
Pick a handle wood and glue that to the core lam. You can pre-saw the tapers but I usually cut them after I glued them up and sand them flat
Now the weird thing, start tillering you bow from the core. This will help you make sure it bends nice and even and prevent surprises after glueing the whole thing in one go.
But don't tiller to full 28 or higher but say tiller to max 18 or 20 inches so you can see it bends even an has nice tiller that conforms to your profile and your reflex.
Now make two really thin bamboo slats for the belly, you can even heat treat them to improve compression resistance and performance but this is optional. I pre-bend the ends with a heat gun so it glues easier up your handle fades

Does this post thing make sense at all? I am not really used to writing howtos O:)
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: globalmark on April 17, 2018, 07:56:14 am
Hi SpringBuck and leon

Thanks so much for all that info - I think I have enough info to actually Make a workable bow Now

Leon you mention make a really Flat Back of Bamboo - any rough thickness as stuff i have bought i planed by hand and could get a good 5-6mm thick out of it - i saw many people mention 1/8" for the back ?
and when you say Thin for the belly what sort of thickness here ???

thanks again guys will post some pics and info when i get around to staring actual build soon hopefully - shop I just tried to Buy glue from was 5 years out of date ..
Thanks Again all
Mark
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: leonwood on April 17, 2018, 08:57:15 am
By thin I mean as thin as possible;-) What I do is I trace the profile of the bow on the bamboo and cut that out with my draw knife (a few mm wider obviously), then I make the bamboo as thin so the edges are sharp and you really can't take off more without losing width. I do this for both the back and belly bamboo.
This also has the benefit of automatically tapering the bamboo a bit in thickness which helps keeping the tiller pretty after glue up
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: globalmark on April 17, 2018, 05:51:18 pm
Hi león

Thanks for all that - gives me plenty to be getting on with ..
thanks Mark

Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: Springbuck on April 19, 2018, 12:07:14 am
Leon:  "You can follow Springbucks advice above and that will work for sure but is probably a little harder because once glued up there is not much wiggle room to change your draw weight or tiller."

  Whoa, whoa, whoa, wait up a minute!  I think ADVICE" is too strong a word. ;D  ;D  ;)

  These are just memories of how once, long ago, something kind of worked ok..... trying to share what I remember, and hopefully he can cherry pick a bit.

  Results may vary...
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: globalmark on April 19, 2018, 10:10:05 am
Hi Guys
I want to say Thanks for advice - or suggestions so far
I was starting clean up the Bamboo today and just couple questions about the general measurement (not Including Leon's last post)
but

 a question on general Bamboo shaping -
1. also Dimensions given on Bamboo thicknesses are these measured in the edge or the middle of the bamboo as it curves higher (obviously bamboo is thicker in the Middle (so am i trying to get edge knife sharp with a eg a 1/8' in middle or leave edge 1/8" - 1/16" etc ?


2.I Just started to try and taper them -
but due to the Nodes on one side and as its a natural shape when you plain or sand them how do you get it a even Parallel or even Taper - as at looking from the side it looks like waves a bit if you know what i mean ..
do i need to put something in-between the nodes to stop dipping or is it really not that important (being a cabinet maker i like it precise )

Again Cheers Guys
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: Jesse on April 19, 2018, 10:56:44 am
You will never get it precise. The back will stay wavy. Just get the belly flat so it provides a good joint between the lams. Go as thin as possible at the width of your bow leaving a thin edge. Since bamboo is thicker in the center in general you will notice it gets thicker out towards the tips after you cut out the bow. I don't mind the reverse taper look on mine because it actually makes lighter tips due to the fact that I use a heavy belly wood. To avoid this cut out the bow shape and then re-sand to a consistant thin Edge.
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: Dances with squirrels on April 19, 2018, 11:13:46 am
I run the bamboo backing piece over the jointer to flatten the underside and get rid of the bulk of the waste. Then cut it out to the front profile, slightly oversized, smooth and straighten the edges, then do the rest of the thinning and tapering by hand with a toothing plane. As I'm doing that, I have it laying on a flat piece of lumber(nodes touching the lumber), with pieces of 1/8" rubber strips supporting the bamboo between the nodes, so they won't push down as the plane travels over that area. It works rather well.

A single clamp holds the bamboo on its end so it doesn't slide around. I work the plane away from that clamp, and when I need to thin the area near the clamp,  I move the clamp to the other end, and work in the opposite direction.

Be careful with that bamboo, as you thin it, the edge can get as sharp as a knife and cut you.

Too bad you can't get Osage over there. I feel for you.
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: Jesse on April 19, 2018, 11:24:24 am
Here is an example of the tip vs. The handle bamboo thickness.
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: Jesse on April 19, 2018, 11:26:51 am
Handle
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: Dances with squirrels on April 19, 2018, 11:30:43 am
Measured at its crown/highest point, I like the bamboo(backing piece) to be 1/8" thick in the handle area, and 1/16" thick at the tips... or very, very near that.

Coming off the jointer, there may be places that the edges are knife-sharp, but then its cut to profile, which gives you little flat sides again, then thin it with the tooting plane, or whatever, to 1/8 to 1/16 to the crown as noted. If the 'cut to profile' method is used, after its done, there's approximately 1/16" flat sides all the way around... if that makes any sense.

I make my bamboo backed bows with wood lams underneath, and leave the wood full width until after glue up... usually about 1 1/2 to 1 3/4".

This is all explained well in Dean Torges' DVD Hunting the Bamboo Backed Bow.

Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: Jesse on April 19, 2018, 11:32:20 am
Another method for thinning the bamboo and flattening it and also the method that I use. Take a long piece of the pink extruded styrofoam like they use on foundations. Put the node side down and press them into the foam. Then run the 2 through a thickness/ drum sander. Comes out flat. I have also just done it by hand eyeballing it on a belt sander and that works well also.
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: globalmark on April 19, 2018, 01:11:05 pm
Hi Guys
Thanks for the replies

I actually Just used a Long no-7 plane (pretty long heavy plane) and can make it pretty smooth and dead flat and straight that took just a few minutes to get flat - just a quick belt sand after that and is perfectly flat and smooth .
I just was not sure if measured from Edges or the Middle - "so seems mainly the middle part" - cheers

Thanks for the suggestions of using Foam or Rubber strips - I actually clamped exactly the same as Dances with Squirrels already and planed it but was thinking best put something under the node spaces .. - but still got to remove more as at moment the sides are that thickness so will do a bit more tomorrow .

- Does anyone know on Tempering Bamboo - heat treatment - how much supposed to do ?? i got my blow torch out and made even as possible the belly - but turns brown pretty quick -
Thanks again Guys Much appreciated .
Mark
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: DC on April 19, 2018, 01:22:12 pm
If you do a google search on "tempering bamboo" there is a lot of stuff the fly rod makers have posted.
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: Springbuck on April 19, 2018, 03:39:23 pm
1. also Dimensions given on Bamboo thicknesses are these measured in the edge or the middle of the bamboo as it curves higher (obviously bamboo is thicker in the Middle (so am i trying to get edge knife sharp with a eg a 1/8' in middle or leave edge 1/8" - 1/16" etc ?


2.I Just started to try and taper them -
but due to the Nodes on one side and as its a natural shape when you plain or sand them how do you get it a even Parallel or even Taper - as at looking from the side it looks like waves a bit if you know what i mean ..
do i need to put something in-between the nodes to stop dipping or is it really not that important (being a cabinet maker i like it precise )

Again Cheers Guys
 

  Measure the thickest dimension, which is the crown.  Getting an EXACT thickness taper is pretty much impossible.  You will have thin spots, then thicker at the node.     One important starting point is to use the largest diameter bamboo you can find, from a species with less pronounced nodes.  I would try to get as much length between the nodes as possible and get as much of that space consistently thick, then just leave the nodes.  Unless you are going for just such a look. 

It all comes out in the tiller.   One idea I had, but haven't tried, was purposely using bamboo with closely spaced nodes and placing the belly nodes between the back nodes.  Lot's of lumps, but maybe average things out? 
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: globalmark on April 19, 2018, 05:10:12 pm
Hi Springbuck

Thanks for that clarification - "crown" yes thats the word i needed .
Not much bamboo choice here in the UK as well as Exotic timbers for core , the Boo i am using posted a Picture on 1st page - its sold for Bow makers in 2.4m x45cm lengths 6-8mm thick so plenty to use - Nodes are as is so not much choice but looks like great stuff .

Thanks for all Help
regards Mark
Title: Re: Help needed with dimensions for laminations on reflex/deflex Bow with BOO
Post by: Springbuck on April 19, 2018, 05:59:15 pm
 Indeed.  I kind of meant "in a perfect world",  but use what you got, right?