I would say that being a full grown adult, you're less likely to get injured with a properly fitted fingertip ball than you are with a properly fitted conventional grip.

Conventional grips cause more injuries than they prevent because they promote more muscling thus more stress on tendons. An improperly fit fingertip ball will cause injuries as well, so make sure the person that fits you doesn't stretch your span.

You can tell if your span is correct by placing your thumb in the ball and laying your fingers across the holes. The leading edge (side closest to the thumb) of the finger hole should be no longer than half way between the first and second knuckle of the middle and ring finger without stretching your hand, it should be relaxed. It can be a little shorter than that, but not shorter than one quarter from the second knuckle.

The thumb should be tight enough to where you don't have to squeeze it to hang onto it. The top edge of the hole should be a little bit sharp so it digs in a little bit at the base of your thumb which may cause a blister and a callus which is normal.

Keep the forward pitch in the fingers to a minimum so you don't callus up your fingertips. If you start out with 0 pitch in the thumb you should be fine until your hand learns to relax more, then you might start squeezing the thumb to hang onto the ball, it sounds like you have a good feel for that so you might want to consider starting out more forward than 0 but I will leave that up to you.

So if I have calluses at the tips of my fingertips (middle/ring), what does that mean?

Hey Jim, a couple of questions. On the subject of not squeezing(yet again), one should be able to hang onto the ball even while keeping their thumb straight, and maybe even pressed to the back of the thumb hole. Is that correct?

My other question is about the top edge of the hole. Are you saying that with less bevel the thumb hole will "grab" on the your thumb on its own? If this is the case, I don't quite understand the reason behind this. Could you possibly explain it more in depth?

Thanks.

Check out this site. You'll probably find an answer.

Finger tip calluses

Yes this is the case, you want to be able to swing the ball with your thumb straight or the back of your thumb pressed to the back of the hole, but when you do this it pushes the base of your thumb forward and you can then relax the thumb and the top edge of the thumb hole will lock itself onto the base of your thumb. Pressing the thumb deeper into the hole while doing this helps lock the ball onto the thumb tighter, but if the edge of the hole has been beveled off (this is common) then the locking effect will not happen.



If the thumb is locked into the ball then you don't have to bend your thumb knuckle to hang onto the ball in fact you don't have to hang onto the ball at all, as it will now hang onto you and gravity will pull it off your hand at the bottom of the swing very quickly and you will get more revs. If you have to bend the thumb knuckle to hang onto the ball then you have to unbend it at the right point in the swing to let it go and that is too much for anyone to try to get right every time.

This is why I recommend Bowling This Month magazine to everyone of my clients. Rolf Guager has written about his thumb locking technique several times and I have learned it to do it by reading his articles. It goes like this: Start by keeping your thumb nail in contact with the back of the hole, then push the thumb all the way into the hole, and let it come back a little so that the base of the thumb locks in on the edge of the hole.

Note that if you try this with an ill-fitting ball, it won't work. It *requires* correct pitches, spans, and tightness. I had a bunch of bevel and some reverse when I first tried it, and it failed miserably. If that's the case - the ball does not lock onto your thumb - you need to fix your fit.

I'm amazed at Chris Warren bowling on tour with the conventional grip. Are there any other pros that bowl this way on tour, too?

Thanks for that information Jim. I'm still a little iffy on how to get the lock effect but that was still helpful. So, after my thumb hole has been drilled how much should it be beveled? Just enough to get rid of the sharp edge of the thumb slug that would cut the base of the thumb? Or are you not supposed to bevel it at all and if you're not squeasing it won't hurt your thumb? This information will be handy because my driller bevels the entire part of the slug where the bae of the thumb sits so that it's really smooth.

As for ill-fitting equipment not allowing the locking of the thumb, it's possible that my ring finger span is a little stretched. And my pitch in the thumb is 1/8 reverse(one has 1/8 forward for testing purposes) but I've never not had to squeeze so I don't know what the right pitch will be.

It should be beveled to a point that its comfortable but still locks the thumb in. Start out with the least amount bevel, just enough to kill a hard edge and then use it some and if it needs a little more bevel take it down a little more. You can add bevel, but you can't take it away short of re-doing the thumbhole.