Start by drilling a round "pilot" hole, then shape it with an end mill.
In tenpin bowling, bowlers who are having difficulty with release, usually related to the ball sticking on the thumb, will sometimes have a very small hole drilled just below the thumb hole, at angle that enters into the lower part of the thumb hole. This is to allow air into the lower region of the thumb hole and prevent a vacuum from taking hold.
Get a halfway decent drill. I'm assuming it happens right at the base of the thumb? What you probably need to get done is have the thumb hole moved a little right and up (if you're right handed) or if you're left handed get the thumb hole moved left and up.
For plastic, urethane or rubber inserts, a hole is drilled the size of the outer diameter of the insert to be used. Care must be taken to factor how the span of the inserts are placed with where the holes are placed. After drilling has been done, the inserts are glued in. While thumb inserts can be replaceable, it's more common to drill a large hole where the thumb goes and a solid thumb insert is glued in the hole. The thumb hole is then drilled into the solid insert.
3. two fingers, one thumb *unless ball has a balance, or weight hole to make the ball USBC legal.
This used to be a very popular way to drill balls--one finger hole, one thumb hole. My grandfather was a very avid bowler, and he always drilled his balls with two holes. No one does it anymore, but it's still legal.
They don't HAVE to have three holes - people used to drill two holes and palm the ball, but it's easier to control the ball with three holes.
There is usually 3 holes in a Ten Pin Bowling Ball. 1 large hole for your thumb and 2 smaller holes for your middle and ring finger. Some bowlers may have different numbers of holes based on their bowling style.
u can have up to five (one for each finger) but most balls have 3-4 holes. one for thumb, one for middle finger, one for ring finger, and for higher preformance bowling balls, they usually have a counterweight hole so that it balances the ball ass it rolls down the lane.
Zero, the ball is smaller than normal bowling balls and it fits into your hand so you don't need finger holes in order to roll it.
yes
Drill a small hole in the ball. Take a back out screw driver and pull it out.
A proshop operator drills a bowling ball the same way for left handed bowlers as they would a right handed bowler. Proshop operator use measurements for span, hole sizes and pitch angles based on the throwing hand. So they will measure the left hand for left handers and the right hand for right handers.