Itty Bitty Osage

[tanner]

Hello all - a little sanity check please. I have a small osage bow I'm making for my 5-yr-old. I'm currently working on tillering and have a couple questions. First - the prop twist. I read a recent thread about string alignment. The gist was that if you look down the bow from the tip and the limb twists left (counter clockwise), you scrape the right side. I've done this some and it's not coming out. Then I realized that the above advice is only relative to which side is UP when you're sighting down the bow. If the back is up, the "right" side is different than when the belly is up. Can anyone please clarify this for me? I think I might have done it bass-ackward and made it worse.

Question 2 is just a tillering sanity-check.

The limbs appear to be fairly well balanced at brace:



Here's my elliptical overlay to try and help me finish the tiller:



As I look at the last pic, my read is that my outer thirds are too stiff. Am I getting this right?

Thanks much!

[adb]

It doesn't really matter, as long as you remember: the limb is twisting towards the weak side. If you hold the bow at brace with the back down and the belly up (which is the only way to check string alignment), if the limb twists left (counter clockwise), remove wood from the high side (the right).

[tanner]

That makes more sense - thanks. I think I needed to think of it more as string alignment than twist. I just picked it up as braced and looked at the end while I drew the string a little. It turns out I had the back up (again - not looking at it as string alignment through the handle). SOooo I made it a little worse, but the good news is that I have some room to go so I'll try to correct it some.

Thanks again!

[Pat B]

Is the twist in the unbraced limb or only when the bow is braced?  If only when braced check the limb thickness from side to side. Generally that is the culprit. Remove wood from the thicker side.   If it is in the limb unbraced don't worry about it. It will have very little ill affects on the bow if any.   What weight are you shooting for?

[PAHunter]

adb and Pat are right on.  Another way to think of it is the side of the limb that is closer to the string of a braced bow needs wood taken off.  Take some wood off and watch the limb straighten up as that side weakens.  Good luck!

[SLIMBOB]

Prop twist (to me anyway) is visible when there is no string on the bow.  If that is what you have then just make sure the thickness is the same on both sides of the limb (with a caliper or something similar) and call it good.  String alignment is a horse of a different color and may have little or nothing to do with the prop twist.  As Pat B said, once strung the prop twist may not even be visible any longer.

[bubbles]

In regards to your question #2: be careful of overlaid ellipses in Photoshop. If you follow it strictly, you will end up with weird hinges near the tips.  The areas near the end of the ellipse increase in curvature, which is (usually) the exact opposite of what you want your bow to do (i like the tips a bit stiffer) if I use Photoshop, I make the ellipse a fair bit larger than the bow, or use a circle, but also check it without the overlaid shape to see if I can see the problem without the aid.

[ohma2]

agree with slim a friend has a stick that looks like a twisted mess braced but drawn it is pretty much all gone,wouldnt believe it to be the same bow at full draw.

[tanner]

Solid advice - thanks guys! I believe one of the limbs is twisted when unbraced and the other is not. I think I have enough to rebalance them and finish it up. Hopefully I'll get some time tonight.

Thanks again!