Limb twist help!!!

[Apex Predator]

I think I have a flaw in my form, because I have had problems with limb twist on the last couple of bows.  I thought I knew how to correct this, but am having my doubts.  I have been removing wood along the side of the limb on the right, but think it may be getting worse.  I have trouble wrapping my head around this theory of wood removal to correct side lean, or twist.  What to do?

[Ryano]

Stop! Removeing wood unevenly doesnt work ! It only causes more problems......Your going to need to make a heat correction. Looks to me like your getting some lateral bend..Is the bow still pretty heavy? You may be able to correct it some just by finishing tillering to your draw weight, but only remove material from the belly not the sides.

[Apex Predator]

This is a liaminated bow with TB3 for glue.  The glue will release at around 155-160 deg.  I don't think heat is the answer.  I have corrected this in the past by taking wood off of one side of the limb, but can't remember which side.  There is conflicting info on the subject.   It is still very strong.  It is pulling my target of 55# at brace.  I wanted to get an even brace before removing wood from the bellly to reduce weight/tiller.

[adb]

Ryan is right, heat is best to correct twist. However, you can try to remove wood on the high side of the twist. In other words, if you're looking down the limb. and it twists to the right, you can try to remove a bit of wood from the left side of the limb, on the belly only. Remember, the wood will twist towards the weak side. Be careful, don't remove too much wood, and go past your intended target weight. Also, if the twist isn't too bad, you can just live with it. It really doesn't affect the bow's accuracy or performance. it just looks like crap. I don't like prop twist either. It just doesn't look right.

[Apex Predator]

All my bows have a rectangular limb cross section at this point in construction.  Should I be rounding the belly right off, before I start tillering? This problem has arisen with all my narrow bows.

I worked this one quite a bit this morning, but it was giving me fits! I measured the limb thickness along the edges of both limbs on each side. It was not off much, but I made them way off trying to correct the twist. Nothing I did made much of a difference. I finally clamped the handle section in my vice and tweaked the tips over toward center several times while braced. This helped more than anything. Now I have removed so much wood that I will have trouble making 50#.

[Ryano]

Hate to say told ya so, but........
Been there done that. If you had used urac instead of titebond you could have heat corrected the problem for sure. I have had some luck with minor heat corrections using titebond 3 but your right, if you get it to hot it will delaminate on you. To answer your other question, yes I round my limbs before I begin tillering.

[adb]

Have you shot the bow yet? If it shoots OK, just live with it. A bit of prop twist is really no big deal, except it looks kinda bad. Working with organic materials has limitations. Just shoot it.

[Rich Saffold]

Marty,
Ipe won't bend with heat anyhow so thats out.

 In addition to what I wrote on the PP forum your tips are also too constant in width and too deep in thickness..This also causes the limbs to twist one side or the other..

Plus usually when they both are on the same side the bamboo isn't even as well...

Shortening the bow and tapering the tips opposite to the bend is your only real solution...And getting it looking much more like a bow before stringing it..like rounding the limbs On a bow like this your tips have to look like points, or very close..

And if its close to straight you can put side nocks on it..and they can look real slick if you get them right...

Rich

[George Tsoukalas]

Was it a twisted stave? I don't see much of a twist at all. Sometimes the twist is caused by uneven wood removal. Like Ad said remove wood from the highest side or where the distance from string to bow is the greatest. Sometimes the twist is just in the wood. I remember working on a yew bow. I was careful to remove wood evenly- to the point of checking the limb with a gauge. When I strung it, it was a leaner. So I removed wood from the side furthest from the string. No more leaner. Heating is the last option for me. It's gotta be pretty bad before I use heat to correct a twist. Jawge

[Apex Predator]

This was at the first brace stage of tiller.  I got it pretty close and now have it tillered to 18".  I have been leaving the belly flat when I get to this stage in the past.  I guess maybe I should round the belly some before bracing it?  I haven't been rounding the belly any until almost finished with tillering.  Does a flat belly make them laterally unstable?  Thanks guys.

[Rich Saffold]

Don't round the belly so much as just round the edges a bit. If the bow bends or flexes through the grip then used the rounded belly, if you have a rigid grip use a flat belly..

These bows being more slender than what is "normal"  means the alignment can be a bit more critical. Also how you go about it is different than with NA bows, and so on...Don't pull wood from the opposing sides unless its wide like over 1.25' since you should have the belly symmetrical before gluing up. This is why getting a good floor tiller on the belly matters..

On these bows when both tips go to one side it usually

The bamboo isn't even
The taper straightens out to much, in either height or width.
the cross section is too tall in a section or all the way

Before gluing these bows up hold the two sections together and look at them and check for the above 3..

[Apex Predator]

I had everything looking really good before glue up.  They only thing I can think of is the ipe maybe having some funky grain structure that I can't see.  I think this one will come out ok.  I'll know more tonight.  I'll keep you folks posted.

[sailordad]

you could just keep reducing the weight and when it quits twisting,wha la    a great kids bow.

after all kids need bows too

[Apex Predator]

Well, I worked out most of the twist.  It will probably finish at 40@27.  She shoots real well though.  I built up a leather grip that I think I'm gonna love.  I'll try to post some finished pics tomorrow.

[Apex Predator]

This is my first bend in the handle bow.  She is a bamboo backed ipe,62" NTN, and draws 40@27.  She has elk antler tips and a built up leather grip.  I'm getting really good at these 40 pounders.  It wouldn't be so bad if they weren't intended to draw 50-55.  I had some limb twist issues with this one early in the tillering stage and had a time working it out.  I think it could bend a little more in the fades, but shoots really well so I'm leaving it.  Luckily, I have a good buddy who needs his first traditional bow.  Perfect for him.