Here is a span to pitch guide.. based on the span and the thumb flexibility it will tell you what your thumb pitch should be..

http://www.innovativebowling.com/images/charts/Thumb_Angle_Conversion_Pitch_Chart.gif

7/8 reverse would be used for a span from 6 1/8 to 5 5/8 inches

what is your span?? Anywhere close to that..
A stretched span will need more exaggerated reverse to get out of the ball. or a ton of bevel.. or both..

Oh boy! - CoachJim!!!

There is a set starting point for thumb pitch and span. But you have to go from there. So many poeple knuckle the ball and pretty much NO ONE of those really wants to work hard enough to eliminate it. Especially the seniors. So a driller has to work with knuckling bowlers.
6" span is huge. So the pitch reflects that.

Yes, bowlers are knuckle heads!

According to the charts, I should be about 1/8" reverse for my span. In reality I started with 1/2" reverse because I used to grip the ball hard and also had a stretched span (didn't know any better at the time). Since opening my own shop and getting some bowling lessons, I have worked my way up to 3/8" forward, and have also gotten my span to the correct length. As Erin said, those charts are a starting point but shouldn't be considered a de-facto standard. I actually don't even look at my charts much anymore, I ask how the person releases the ball, how much they think they grip ("do you squeeze it to death or just hang on to it a little?"), check their flexibility, and go from there. The nice thing about the measuring ball that most shops use is the ability to try different pitches and spans on a person without actually drilling a ball, and while it isn't an exact representation of how your ball will feel, it is a good starting point.

That said, if some one is determined to use their numbers or brings me a ball that just doesn't seem right but swears by the measurements, I will drill it that way. I want it to be how I think is best, but I want it to be how the customer wants it too. I recently gained a couple of customers because their longtime friend / ball driller refused to change their pitches, despite the pains they had with their fingers.

In regards to your thumb pains, it sounds like you either have the wrong lateral pitch or you need a larger oval. Given that they are on both sides of your thumb I would lean towards you needing a larger oval.

Also, the pin to cg distance does matter (but ONLY because of current rules), it's the static weights that aren't so important anymore. USBC determined that static weights effect less than 5% of a balls reaction. But putting the weight block into a specific position based on your PAP can change how it reacts for you. If the layout you want puts the pin 1.5" above your fingers then with a pin to cg distance of just 1" on the ball that would put the cg 1/2" above the fingers. There is no way you would be able to remove the extra finger weight to bring the ball into legal static weight with such a pin to cg distance, so either you have to change the layout (possibly giving up your desired reaction) or get a different ball with a longer pin to cg distance. Hopefully in the future the rules on static weights will go away, but until then pin to cg distance does matter.

Where in Texas are you?

Sorry txbowler, don't mean to hijack your topic but I have questions of my own about this subject.

TenPin, out of curiosity, what do your spans and pitches happen to be?

I have 1/4 left and 1/8 forward right now pitch myself. For a while now, I've had some rubbing/dragging around the right side of my thumb(looking at the back, pointing up) and I can't seem to get rid of it no matter what the lateral pitch is. I might even want to move the thumb pitch more forward but I have a feeling the span is a little long since the area bothering me is near the part of the thumb hole closest to the fingers. I do have an oval thumb hole. I'm not 100% sure I'm doing the span test right but if I am it seems mine could stand to be shortened. If I explained my problem well enough, could it be possible the span is off?

I've heard unless the span is right, pitches are irrelevant and that's sort of how I feel. Right now I keep my thumb hole bigger than it should be so I can get out of it well enough. It forces me to maintain grip on the ball until release but if I keep the hole as snug as I'd like it I risk slight hanging or losing it early(when relaxed). An over/under in ball fit so to speak.

There's your answer.

If you are gripping with the thumb (even if you are gripping with a straight thumb), the thumb will rub on the edge of the hole as it comes out because you are still pressing the thumb against the ball - against the edge. I've seen this lots of times on slow motion release videos... Maybe I can dig one of those videos up and show you, if you want.

As far as pin to CG distance, as TenPin said, it matters because the ball has to weigh legal. If you have a short pin to CG distance, you can't put the pin real high, without balance holes, drilling a finger or two into the core, etc..

The other reason they matter is because you may want a balance hole to change your reaction. You'd then pick a ball with an appropriate pin to CG distance so you could place the CG in a position that would allow you to put the weight hole where you wanted.

My cut to cut span is 4 1/4" (middle finger), 4 5/16" (ring finger), 1/4" left lateral in my middle finger, 1/2" right lateral in my ring finger, 5/16" reverse in my fingers, and 3/8" forward in my thumb. Thumbhole is 57/64 with an 060 oval at 35*.

I agree with Luksa that having an oversized thumbhole and knowing you have an oversized thumbhole is probably causing you to grip it more than you should (whether conciously or not), which in turn is going to cause some rubbing. Another thought I had is if you are turning your hand around the ball too much you could be putting more pressure on the side of your thumb. I have worked with some people who not only got on top of the ball but twisted their hand around so far that their hands were practically on the front of the ball at the release point, which causes a lot of problems. That's pretty extreme, but it does happen and they weren't even aware of how far around the ball they were getting. Where is your hand / thumb pointing after you release the ball?

I'm a tweener. My Track has changed since I got the span/pitch changed. Medium Track and further from my thumb than it used to be. Inch and a half or so from what I saw on Wednesday. Used to be much closer like yours.

My span is 5 x 5 1/8. I am at 3/8 reverse. I also have a very flexible thumb/fingers. Like Gumby basically. 7/8 is WAY too far. What is your span?