You can drill the ball without unclamping it after each hole.  Holds the ball very solid, no chance of knocking the ball off the press while cutting down plug or slugs.

That being said, "I" prefer the Vacu Jig milling system.  I love how fast it is to lock and unlock the ball.  99% of the time no problems.  Every so often you encounter out of round balls, too small balls, holes across the o-ring, etc, that make getting a good vacuum tough.  Usually this can be solved with modeling clay or duct tape.

Good luck, wish I was buying a press!
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Ahhh, Pro Model.  My bad, missed that part.

Only drilled 2 balls on a Pro Model.  A friend here in Oklahoma has one at his house.  Holds the ball very solid.  Figuring out how to set the pitches was tricky/confusing.  Once you do that you should be fine.  Very smooth.  Motor has enough power.  Only thing you won't be able to do is mill oval holes.  Good luck!
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