Tillering a glass laminated recurve

[Dave521]

This may sound a bit dumb, but I am new to building glass and wood laminated recurves and was wondering if someone could explain how you tiller one. I have a friend that has a beautiful bow that is un-usable due to the fact that the tillering is of and the string comes off everytime he shoots it and when you look down the limb one side is bent more than the other, can this be corrected easily or is it a wall hanger? any help would be greatly appreciated since I am almost to the tillering stage on the bow I am working on and have to much time invested to just make a wall orniment LOL

[Pat B]

Most of the tillering of a glass bow is in the lam selection and laying it up evenly. A bit of adjustment cam be made by scraping the sides of the limb(s). I don't build glass bows so someone more knowledgeable than me should chine in soon with an answer for you.     Pat

[DCM]

"Tillering" in the glass bow game has a different meaning than in the selfbow game.  It's what we would call correcting limb twist, and the methods are the same.

Unless there is a structural flaw, ie. the form was twisted, you can correct limb twist.  The idea is to have the string line up perfectly with the center of the bow.  Adjust the string grooves and/or the limb width as necessary.  The strong side or stiff side of the limb will bend less, so remove material from the stiffest, straightest side.  If the center line is achieved perfectly and you still have some twist, you can sometime coax the limb straight by a) bending it beyond straight in direction opposite the twist and b) doing same after application of very mild heat, say 110 degrees F max.

I don't actually know shiite, but I've built a couple of glass bows from scratch, corrected mild twist in a few production glass bows, and corrected limb twist while building about a bazillion self bows.

[BMN]

I saved a copy of this sketch someone sent me some time ago. It may help.

 

[Dave521]

thank you for all the pointers, I am sure I can get it taken care of with what you ahve told me. thank you very much, I know my buddy will be happy