Most peoples fingers taper from the hand to the fingertip. If you Drilled the hole at just the size of the first joint, you wouldn't be able to insert your finger all the way to the second joint.
So in a conventional grip, the bowler's ring and middle fingers are placed into the ball up to the second joint, while in a finger tip grip the ring and middle finger holes are made to accept the bowler's fingers only up to the first joint.
Bookmarks