I want to try drilling the balls myself. I wonder what kind of drill bit I should get? I went to Home Depot and they only have larger size bits for concrete. Nothing really big for metal. Do I need metal drill bits for occasional drilling into the core? What are they made out of? Does Sears have those bits?

Thanks for your help!

Do you have a jig to hold the ball and set your spans and pitches?  And a drill press with enough quill travel to allow you to change bits without removing the ball from the jig?  If so, Jayhawk is one of several websites where you can buy new bits, and they're all priced about the same.  Or you can watch e-Bay for used bits.  If you use finger grips and a thumb sleeve you can get by with two bits, 31/32" for the fingers and either 1 1/8" or 1 1/4" for the thumb sleeve.  Or if you want to just drill a thumb hole in the ball substitute the proper size bit for your thumb instead of the bit for the sleeve.  If you want to use a slug you'll need both a 1 1/4" bit and the bit for your thumb hole.  --  JohnP

www.bowlingindex.com - lot's of pro shop stuff at decent prices.  Including single drill bits.