i am a one handed bowler but sometimes i throw a 2 handed back up ball for ten pins (works pretty good for me) would i have to plug up a thumb hole on a ball to use it for that even if i use it one handed most of the time.

i used to be able to throw straight at a 10 pin but since i started getting better roll and revs i haven't been able to. i started throwing the back up when i went up for practice one sunday and i missed 4 ten pins in one game and i wasn't even close, stood far left and threw a straight ball, but it went straight where the 7 would have been. haven't had any luck changing back either

I would have thought so long as you have the  very tip of your thumb in the hole then you will be complying with the rules. Even a finger from the opposite hand in the hole as you are using that hole then. May have to check if that’s legal but would have thought it’s ok.

That shouldn’t be too hard to practice for you.

I would have thought so long as you have the  very tip of your thumb in the hole then you will be complying with the rules. Even a finger from the opposite hand in the hole as you are using that hole then. May have to check if that’s legal but would have thought it’s ok.

That shouldn’t be too hard to practice for you.

would have to guess that it would be illegal to have fingers from both hands in the ball at the same time

You are hooking polished plastic shooting at 10 pins?  Polyester making the pattern disappear is well worth how cheap it is.

Quote from: tritonj on May 07, 2019, 01:46:07 PM

Quote from: star on May 07, 2019, 01:58:35 AM

I would have thought so long as you have the  very tip of your thumb in the hole then you will be complying with the rules. Even a finger from the opposite hand in the hole as you are using that hole then. May have to check if that’s legal but would have thought it’s ok.

That shouldn’t be too hard to practice for you.

would have to guess that it would be illegal to have fingers from both hands in the ball at the same time

Like I say it may be legal as in scratch tournaments, “handedness” is not counted separate. I have played in many where right handed bowlers have bowled left handed at splits. That was deemed legal. In handicap events you have a separate handicap based on hand used.

Like I say you would have to check. I honestly don’t know for sure.

"handedness" would be irrelevant, if i remember correctly the new rules clearly state all holes must be used for gripping the bowling ball 

Edited:

According to the USBC Rule Book, Chapter 8:

a. Effective through 7/31/2020:
1) Holes.
a) Holes or indentations for gripping purposes shall not exceed five and shall be limited to one for each finger and one for the thumb, all for the same hand. The player is not required to use all finger holes in any specific delivery, but they must be able to demonstrate, with the
same hand, that each gripping hole can be simultaneously used for gripping purposes. Any thumb hole that is not used for gripping purposes during the delivery would be classified as a balance hole.
b) One hole for balance purposes, not to exceed 1¼-inch in diameter is permitted. (Slugs and bowling tape will be allowed in balance holes; however, interchangeable devices are not allowed).
i) Any hole that cannot be reasonably shown to be used with a single hand is classified as a balance hole.
ii) Balance holes may not intersect gripping holes.
c) One vent hole for each finger and/or thumb hole, not to exceed 1/4 inch in diameter is permitted.
d) One mill hole for inspection purposes not to exceed 5 ⁄8 inch in diameter and 1⁄8 inch in depth is permitted.
2) Balance. For balls weighing more than 10.00 pounds (all measurements are to be taken with
respect to the center of grip):
a) No more than 3 ounces of top/bottom weight.
b) No more than 1 ounce of left/right side weight.
c) No more than 1 ounce finger/thumb weight.
d) A ball used without any holes or indentations may not have more than one-ounce
difference between any two halves of the ball.
b. Effective 8/1/2018:
1) Holes.
a. Holes or indentations for gripping purposes shall not exceed five and shall be limited to one for each finger and one for the thumb, all for the same hand. All holes must be used on every delivery. If a bowler does not use their thumb, there must be a scribed or engraved cross-hair lines (“+”) near the center of the palm to indicate the grip orientation. The ball must be delivered in the marked orientation (i.e. palm must cover the “+”).
b. No balance holes are allowed.
c. One vent hole for each finger and/or thumb hole, not to exceed 1/4 inch in diameter is
permitted.
d. One mill hole for inspection purposes not to exceed 5 ⁄8 inch in diameter and 1⁄8 inch in depth is permitted.
2) Balance. For balls weighing more than 10.00 pounds (all measurements are to be taken with respect to the center of grip):
a. No more than 3 ounces of top/bottom weight, left/right weight and finger/thumb weight.
b. A ball used without any holes or indentations may not have more than one-ounce
difference between any two halves of the ball.
For center of grip determination and balls weighing 10.00 pounds or less see the USBC Equipment Specifications Manual.

https://www.bowl.com/Rules/Rules_Home/USBC_Playing_Rules/
.

The rule is simple ----

if there is a hole in the ball, it must be used EVERY SHOT you take with the ball.