Lam Bow Limb Center Finder

[HalfRack]

So I’m working on a new style bow, I have a lot of work already into it and don’t want to screw it up.

 

I wanted to make a limb center finder like what Hera did so here's my version, made of super strong plastic. I made the location of the nock at about the same place as the nock would end up on the limb.

 

 

I wanted to have a set screw so the thing wouldn't slide around or off the limb, which turned out to be handy to use in stringing the thing up.

 

One limb was dead straight, the other had some lam slippage, didn't look like much strung:

 

But when the stick was added to get the limb brace back about 15 inches there was some twist:

 

So I moved the jig to the direction I thought would take the bend out and it looked good:

 

So the limb center shifted about 1/4", being this is the first time I've tried this I'm hesitant about cutting the limb out intentionally off center, so here I sit trying to reason it out.  Should I go for it, anyone use this type of jig successfully on an iffy limb?  

Thanks.

-Mike

[kennym]

No I haven't ,but I like it!! Keep us posted on this rig!

[stmpthmpr]

If the lam against the form didnt move(if one moves, it is usually the top one) then I would find center of the bottom lam, transfer it over the end/tip to the top one and go from there.

I dont think one need worry about pulling string on the bow before limbs are cut to shape and string nocks cut in. If your form is straight and limbs cut precisely to pattern, and string grooves aligned and cut to the same depth, then a laminated bow should come out pretty close to perfect.

Any little adjustment needed can then be done by filing one side of the string groove deeper than the other.

I draw out my center lines AND my limb shape pattern on both sides of the glass before I glue up. I then check and re-check the lams until Im sure they are straight. A couple little blocks screwed to the sides of the form after glue up and celophane ensure that there is no slippage.

Hope that helps.