I was working on a longbow for a Christmas present today and things were moving right along until I strung it up. It looked like there was a bit too much bend at the tips, so I thought I would remove more wood from the rest of the limbs to even things out. I only removed wood from the fades out to about mid limb. Then I strung it up again and I saw the lower limb hinging badly about 8 inches from the tip.
Here it is on the long string.
(http://i1177.photobucket.com/albums/x349/1wood1/IMG_0641_zpsbcqidqlz.jpg) (http://s1177.photobucket.com/user/1wood1/media/IMG_0641_zpsbcqidqlz.jpg.html)
I unstrung it and it went back to it's original profile right away.
(http://i1177.photobucket.com/albums/x349/1wood1/IMG_0642_zpsrlmmkkzz.jpg) (http://s1177.photobucket.com/user/1wood1/media/IMG_0642_zpsrlmmkkzz.jpg.html)
This bow is bamboo backed and bellied with a purpleheart core and a thin walnut power lam. 68 inches tip to tip and 1 3/8 inches wide at the fades.
Is there a fix for this or is it bandsaw fodder?
Dave.
Remove wood from above and below the hinge until it is gone. Watch the other limb to make sure it stays even.
Thanks John.
What causes a hinge like this? The limbs are both evenly tapered and the core lam is free of defects and is symmetrical in both limbs. The only work I did before noticing the hinge was to sand to my profile and round off the edges a bit to prevent splinters during tillering. Could it be a weak area in the wood?
Dave.
Changes in limb thickness cause exponential changes in limb stiffness .... Fractions of a mm stand between a stiff spot and a glaring hinge.