I've been drilling four fingers for myself for years (pinky finger hole), but I've always been kind of curious whether adding an index finger would be a good idea or whether it would even work.
So I bought a $10 ball off eBay (an old AMF RPM Ultra C pearl) and decided to experiment a little. I've yet to throw it in practice or league but will update this thread when I do.
I did want to pass along information on setup, at least: Not knowing how to set it up and flying completely by the seat of my pants, I first just took the ball, relaxed my hand, and held it. Then I marked the angle away from the middle finger based on where my hand wanted to go naturally.
From drilling pinky finger holes, I've found that a 20-degree angle away from the ring, center-to-center, works best. For pitches, I take whatever the ring is for laterals -- meaning, 1/2 inch away (right). For forward/reverse, if it's a ball I plan to want to swing or know I'll need to rev, I'll take my ring pitch (which is 0, but with inserts becomes a default 1/8 to 1/4 forward depending on which insert I'm using) and cut it in half. So on a 1/4 ring, the pinky will be 1/8 forward. If it's a ball that I'm going to be going more up the back of and shooting off the corner, I'll cut the pinky at 0.
For the index, I decided to just use the middle finger pitch, 1/4 forward. I quickly found out that wasn't going to work. I've got a big backyard with soft grass, and prior to drilling the Ultra C, I took an old cracked Velocity that I use to confirm my drill press is being accurate, and put an index in it, then went out and threw it in the backyard and taped myself.
What I found out was the index finger made me want to turn the ball counterclockwise too soon at release. Instead of being able to stay on the inside part of the ball until the last fraction of a second and then snap out of it, the ball would want to turn earlier and as a result, the ball would come out with different axis/tilt numbers. Obviously, you can't count "grass rings" so this will have to wait until I get to the lanes to confirm.
But I did find that 1/4 forward is way too much and was actually causing some discomfort. So I drilled the one in the Ultra C at 1/8 reverse and, at least when throwing it into an old recliner I have in my shop to test releases, determined that it was much more comfortable than forward.
Early tip: The standard of how to measure proper fingertip length on the fly by using the forward lip of the hole and where it falls on your finger joints won't work here. I feel I need to drill the index shorter by about 1/8 - 1/4 inch. If I'm right, I'll have to plug the Ultra C next week and adjust, but that's the beauty of doing this with a $10, twice-plugged-already ball.
Jess
Edited on 3/8/2009 10:27 PM
