Author Topic: Help needed with dimensions for laminations on reflex/deflex Bow with BOO  (Read 1316 times)

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Offline globalmark

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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


Offline Stick Bender

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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
If you fear failure you will never Try !

Offline globalmark

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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

Offline PatM

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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.

Offline globalmark

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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 ?

Offline Ryan Jacob

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Depends, how deep did you sand?, a picture might help illustrate the situation.
You don’t know desperation till you’ve split a stave with screw drivers.

Offline Stick Bender

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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 !
If you fear failure you will never Try !

Offline Stick Bender

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Also ether style mentioned can be made on a simple 2x4 form
If you fear failure you will never Try !

Offline globalmark

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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

Offline Stick Bender

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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 !
If you fear failure you will never Try !

Offline Jesse

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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.
"If you can find a path with no obstacles, it probably doesn't lead anywhere."
    --Frank A. Clark

Offline Jesse

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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
"If you can find a path with no obstacles, it probably doesn't lead anywhere."
    --Frank A. Clark

Offline Bayou Ben

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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.

Offline globalmark

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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-

Offline PatM

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 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