If buying a drill press to drill bowling balls, what is the minimum quill stroke/spindle travel that I would need? (meaning, the depth to which I could drill)

Most presses are about 3.5 - 4 inches. To get over 4 inches, there's a big jump in price.

Jess

The more the spindle travel the better. Especially when drilling extra holes.

Plus, it is better to have the option of having too much spindle travel than not enough.

You also have to remember that you need a space to be able to remove the ball from the press/jig.

The first press I had had a 2.5" spindle travel. Which for drill a normal pattern (3 holes) is usually okay. But when I really needed to drill holes deeper to really change core configuration, I couldn't do what I needed.

Now I have a drill with 3.5" of spindle travel. That has made it so much easier to change the reaction of a ball with deeper finger/thumb holes or deeper weight holes.
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Larry Verble