Does a twisting limb behave like a piece of aluminum angle?

[Red Dwarf]

I have become pretty confused lately while trying to sort out twisted limbs on a pair of yew billets that I am trying to tease into becoming a bow.
In an effort to clear my mind I looked for an extreme example of limb with a strong & a weak side and came up with a length of aluminum angle. I clamped this in my vise "back down, belly up" and pulled up on the tip simulating drawing the bow. I have attached a basic drawing of how this "limb" moved.
Basically the weaker edge lifted up more than the stronger edge and the whole limb moved laterally in the direction of the weaker edge; ie. the tip moved to the right when the weaker edge was on the right.

If a limb that is straight when unstrung but twists/warps when braced/drawn behaves in the same manner, and I can see no reason to think that it would not, then I think that I have finally got my head around this one.



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[George Tsoukalas]

I could not see that doc. I assume we are talking about a twist caused by uneven wood removal-not a natural twist. Anyway the limbs twist towards the weak side. Say the bow is strung. Measure front and back. The side closest to the string is the weak side. Remove wood from the other side. Jawge

[Red Dwarf]

Jawge

You should be able to view the document by clicking on the document name at the bottom of my first post.

Red Dwarf

[George Tsoukalas]

I can't view it.  Can you post a picture of your billets? Jawge

[tom sawyer]

I saw your drawing (its a Word document guys) and yes, that is what happens.  The weaker sides bends more and the whole thing "rolls" toward the weak side.  It may be that you have one edge slightly thinner and this is causing your problem.  I've had this happen on a few bows, mostly ones that have pretty wide limbs.  When a limb is wide (like 2") you have to make it pretty thin, and at that point a small difference in thickness form one side to another can cause this rolling effect.  You can usually straighten it up some by reducing the strong side.  But you can also avoid it by using a skinnier/thicker limb and makign the bow long enough that the bend won't mash the belly.

[richpierce]

Good explanations.  Generally I am dealing with staves with natural propellor twists and trying to fix that.  I have a locust bow that looks a little twisted and humpy when strung but comes into plane as drawn.  I can't figure out how I accomplished that.

[George Tsoukalas]

OH. If it is a minor twist just leave.  How many degrees? Jawge

[PK]

I could not see that doc. I assume we are talking about a twist caused by uneven wood removal-not a natural twist. Anyway the limbs twist towards the weak side. Say the bow is strung. Measure front and back. The side closest to the string is the weak side. Remove wood from the other side. Jawge

Do you Have Microsoft word 2003 0r 2007 or not at all?

[El Destructo]

What T.S. is talking about is true....I love my Paddle Bows and Pyramid Bows....but to make such a wide limb from a Stave ...means really thin Limbs....and even a 64th of an inch can be dramatic...look at the pictures I attached ....this was all I had to take off to get this Bow back to looking like a Pyramid Bow....and not a Cessna Prop!!!

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