What are the differences between Oval thumb and a Round Thumb drilling? What are the benefits of having a oval thumb? Does it help with ball control? Why some people use round?

I use round thumbs because I use tape to mold my thumb to the hole. The advantage of this is there will be an air gap that will allow air to flow around the thumb and prevent suction in the hole. Oval holes are fine as long as there is air flow either with the slug, or by way of a vent hole.

OK, drill bits are round, most thumbs, nearly 95% are oval. Now maybe 50% can get away with a round thumb hole. But for optimum fit, most need an oval thumb hole.

Why the round thumb?......A lot of drillers are lazy or NOT proficient at ovaling a thumb hole to fit.

Typically an oval thumb hole will fit better from the get go without aid of tape and other thumb aids. Less squeezing needed therefore freeing up your arm muscles and freeing up your swing. A free-er swing will allow more repetition therefore repeating shots.

Most beginner to intermediate bowlers do not know how to fine tune their thumb hole (round or oval) with tape. Therefore an oval thumb is usually a good head start to a better fit. Many don't know what tape is, much less how to put it in the thumb hole.

Erin

Been there done all that $$$ - Oval, Oval, OVAL.
Get the drill bit size from the Pro Shop operator for the front to back - like 29/64 (That is mine with 1 magic carpet with 1 black tape behind it) then request the width bit size: Mine is 67/64. If the Pro Shop operator is using a mill you are set, if they are ovaling with a sander they can stick the drill bit (67/64) in the hole for size testing as they sand. This way, when you need new holes drilled or adjustments made, they come out pretty exact.

~ John

Does the round thumb holes cause more sticking that the oval? Also if the degree of the oval is a little off could that also cause sticking in the ball?

If the degree of the oval is off it can cause the thumb not to come out correctly which will cause it to hang up, or force you to alter your release in order to get out of it. That is not advisable.

Round thumb holes won't cause more sticking unless the hole is too tight on the wide side. That's why some bowlers have the thumb hole opened up which often means running a bigger drill bit all the way around and that's what leads to too large of a thumb hole.

Not everyone needs or can use an ovaled thumb hole. I am one of those that can't use one. The base of my thumb is pretty much the same size all the way around and near the knuckle there is very little difference. A piece of two or tape is enough to make it right. I actually use Magic Carpet in the back side.

What Coach Jim said.


I've used Magic Carpets before. They work and I got a really good release, but after a while my thumb was irritated in back. (prolly means I needed to put in a new piece).

I'm getting dizzy from editing, but most of the drillers I ever met love using the sander, and most of my thumbholes wound up tapered...bigger at the bottom than the top. I prefer a larger rounded hole from the drill and I'll work it out if I have to (by hand) and use tape.

Well here is my problem.. I just got my thumb re drilled and they plugged the old one and put the thumb in more of a 45 degree angle. Perfect fit right now. My other balls has them thumb sleeves in them.. I think thous are too narrow... Is it better to get your thumb drilled better into the ball or a slug because you can shape the hole more proper to your thumb?

Rob, it is trial and error, every hand is different, there is no exact science to fitting the thumb exactly to your hand, it takes several trips to the shop to get it exactly right.

CoachJim, that can't be true. There is a guy in town who told me he has been doing this for X years and will get it right the first time.

Yep, I don't plan on using him.