Anybody try to build their own ball drilling jig? Care to share what you tried and/or learned? My first attempt is a vacuum jig that vibrates too much during drilling (just testing with old balls so far). I think the ball cup is the problem, I converted a Donkee Workstation ball holder to hold a vacuum and I think I have to cut the plastic support webbing off the bottom so that the bottom of the cup sits flat on the aluminum plate.  Or I might scrap that holder and try another one I've been working on, or go to clamps. I'm mounting all my experiments to an X-Y table mounted to my drill press.

Pitches are defined as distance from the center, not the bottom of the ball.  So, for example, 1/4" reverse pitch is !/4" away from the grip center at the center of the ball.  To measure at the bottom of the ball, you would have to cut the distance in half.  --  JohnP

Router mat or the non slip matting you can get fixed in place with double sided tape works great for keeping the ball from slipping.
I use it in my home built spinner and thats got some revs.
--------------------
Happy go lucky bowler from the UK.
   Did someone say tough luck
 Want to learn to read lanes then visit:-
      www.thebowlingprofessor44.com/