Ive been working on a hickory backed osage bow blank that I won recently... This is my first attempt at making a bow.. Today when I was cuting the string nocks in to begin tillering, a 1/4 inch square piece of the hickory backing chipped off the end.... My question is, can I sand the backing down on each end and glue some osage to the tips to beef the tips back up before shaping the tips? If I can what should I use to glue them on?

I don't know why not. use Tite Bond 11 or 111

Can you post a pics? Like in Ranger's pic an overlay should fix your problem.
 Why did a square piece of hickory pop off?

That pic is just what I needed to see.... Some how or another the piece had allready splintered and finally came off while cutting the nocks..

Make sure you file from backing down to the core wood when cutting nocks or you can splinter the backing.

OVER LAYS