Recurves

[DC]

I've been having a bit of a problem getting the string alignment right on this bow http://www.primitivearcher.com/smf/index.php/topic,60803.45.html
What I'm wondering about is not how to fix this particular bow but how to avoid this instability in the first place. I'm thinking design stuff. Limb width, limb length, recurve size and angle. Limb cross section. Front profile. Does any of this stuff make the bow less likely to be unstable?

[wizardgoat]

Don, hard to tell what your really dealing with, but I tweak nearly every recurve I build.
When it's strung, if you can manually torque it and tell that's what's needed to fix it, surely
dry heat is your best option.
I clamp the bow side ways on a caul, and hang a weight off the very tip of the recurves.
I heat the 3" section of limb where the recurve meets the limb.
The correction holds well there, and you shouldn't unravel any of your recurve.
As others stated, very little heat is needed.
Design stuff for sure matters with stability, but in my experiences, staves with any degree
of twist make recurves a little more challenging

[DC]

I'm wondering about future bows. Is there anything I can do to avoid this or at least minimise it or is it just as the hooks get bigger the bow gets more unstable?

[wizardgoat]

Nowadays I only select ideal staves for recurves, biggest thing, no twist.
your bow is quite narrow which probably isn't helping you.
Like I said, I tweak every recurve I make, even if they never throw the string.

[Danzn Bar]

+1 What goat said
DBar

[bradsmith2010]

also keep in mind it does not take much curve to get your performance,, how far the tips are in front of the handle is key,,

[PEARL DRUMS]

Exactly. That may mean you can snip some length of the statics and possible get them better aligned. Im a big fan on small, tight statics. I use a quart paint can diameter bend.

[upstatenybowyer]

Like Goat said, I only make recurves from the straightest and best staves. I don't steam the curves in until the tillering is almost done and I leave the handle and tips wide until the very end.

[DC]

Thanks guys. If a wider limb is better(in this case) do you think a pyramid is any better/different than a parallel limb?

[gfugal]

I have always been afraid to heat treat anything I've already treated, fearing that it will undo what I did. You say a little heat is all that's required. Have any of you ever had your recurve flatten out by doing too much heat

[Pat B]

The recurves I've built have been more like a Mollie shape with wide working limbs that narrow abruptly towards the non working tips. A pyramid will work for a recurve but the narrow outer working limb is more apt to be unstable.

[bradsmith2010]

I am not an expert on recurves, I have made a few,,
when I did alignment,, I heated below the recurve gently and then twisted to align,,, successfully several times,,the recurves did not come out,,

[Danzn Bar]

Ditto what Brad said..
DBar

[mikekeswick]

As said above straight, clean staves are the way to go.
Short sharp recurves.
Parallel width limbs with elliptical tiller are much more stable and resistant to any twist than pyramid, narrow outer limb bows.
Recurves will uncurl if you get them hot enough.
I made a jig to hold the curves in place and allow me to heat the limb up hot enough to plasticize the wood so that I know my corrections will hold (if the tip itself needs heating).
What Wizard said about heating the portion just before the curves is best if you can avoid having to heat the tips themselves.
Adding deflex to the handle area of recurves was the best thing I ever did on my recurve 'journey'! Fresh wood has a faster return speed that wood with set.

[DC]

Nowadays I only select ideal staves for recurves, biggest thing, no twist.
your bow is quite narrow which probably isn't helping you.
Like I said, I tweak every recurve I make, even if they never throw the string.

No twist. Does that mean that a twisted stave will continue to twist as it bends?
 Is that what causes this. In order to get the tips to line up at brace they have to be way crooked unbraced. Is this going to twist more as I draw the bow? Is it possible for it to be lined up at brace but twist enough to throw the string at full draw?