This is an Estimated Weight Hole removal chart in Ounces.
As of August 1, 2020, per USBC rules, balance holes are illegal and are not to be drilled into bowling balls that are intended to use during USBC sanctioned events. A maximum of up to 3 oz. of top or bottom weight and up to 3 oz. of static weight, thumb or finger weight is considered legal as of August 1, 2018, provided the ball does not have a balance hole.
Previously, the USBC stated that a bowling ball may have no more than one(1) ounce of side weight after the holes are drilled.
You need a DoDo scale to weigh the ball for side weight. If you are over one(1) ounce (we recommend 3/4 ounce) then use the guide below to help determine what size drill bit you should use, and how deep you should drill. Please note again that balance holes are now illegal per USBC rules, as of August 1, 2018.
Drill
Bit
Size |
Hole Depth in Inches (Estimated) |
| 0.500 |
0.750 |
1.000 |
1.250 |
1.500 |
1.750 |
2.000 |
2.250 |
2.500 |
2.750 |
3.000 |
| 19/32 |
0.119 |
0.178 |
0.238 |
0.297 |
0.356 |
0.416 |
0.475 |
0.534 |
0.594 |
0.653 |
0.713 |
| 5/8 |
0.122 |
0.184 |
0.245 |
0.306 |
0.367 |
0.428 |
0.480 |
0.551 |
0.612 |
0.673 |
0.734 |
| 21/32 |
0.135 |
0.202 |
0.269 |
0.336 |
0.403 |
0.470 |
0.538 |
0.605 |
0.672 |
0.739 |
0.806 |
| 11/16 |
0.148 |
0.222 |
0.296 |
0.369 |
0.443 |
0.517 |
0.591 |
0.665 |
0.739 |
0.813 |
0.887 |
| 23/32 |
0.157 |
0.235 |
0.313 |
0.391 |
0.469 |
0.548 |
0.626 |
0.704 |
0.782 |
0.860 |
0.939 |
| 3/4 |
0.176 |
0.263 |
0.351 |
0.439 |
0.527 |
0.615 |
0.702 |
0.790 |
0.878 |
0.966 |
1.054 |
| 25/32 |
0.191 |
0.286 |
0.382 |
0.477 |
0.573 |
0.668 |
0.764 |
0.859 |
0.955 |
1.050 |
1.146 |
| 13/16 |
0.206 |
0.309 |
0.412 |
0.515 |
0.618 |
0.720 |
0.823 |
0.925 |
1.029 |
1.132 |
1.235 |
| 27/32 |
0.238 |
0.356 |
0.475 |
0.594 |
0.713 |
0.831 |
0.950 |
1.068 |
1.188 |
1.306 |
1.425 |
| 7/8 |
0.250 |
0.375 |
0.500 |
0.625 |
0.750 |
0.875 |
1.000
|
1.125 |
1.250 |
1.375 |
1.500 |
| 29/32 |
0.263 |
0.394 |
0.526 |
0.657 |
0.788 |
0.919 |
1.050 |
1.182 |
1.313 |
1.444 |
1.576 |
| 15/16 |
0.273 |
0.409 |
0.546 |
0.682 |
0.819 |
0.955 |
1.092 |
1.228 |
1.365 |
1.501 |
1.638 |
| 31/32 |
0.300 |
0.450 |
0.600 |
0.750 |
0.900 |
1.050 |
1.200 |
1.350 |
1.500 |
1.650 |
1.800 |
| 1 |
0.325 |
0.488 |
0.650 |
0.813 |
0.975 |
1.138 |
1.300 |
1.463 |
1.625 |
1.788 |
1.950 |
| 1 1/32 |
0.350 |
0.525 |
0.700 |
0.875 |
1.050 |
1.225 |
1.400 |
1.575 |
1.750 |
1.925 |
2.100 |
| 1 1/16 |
0.368 |
0.553 |
0.737 |
0.921 |
1.105 |
1.289 |
1.474 |
1.658 |
1.842 |
2.026 |
2.210 |
| 1 3/32 |
0.388 |
0.581 |
0.775 |
0.969 |
1.163 |
1.357 |
1.550 |
1.744 |
1.938 |
2.132 |
2.326 |
| 1 1/8 |
0.400 |
0.600 |
0.800 |
1.000 |
1.200 |
1.400 |
1.600 |
1.800 |
2.000 |
2.200 |
2.4000 |
| 1 5/32 |
0.425 |
0.638 |
0.851 |
1.063 |
1.275 |
1.488 |
1.700 |
1.913 |
2.125 |
2.338 |
2.550 |
| 1 3/16 |
0.450 |
0.675 |
0.900 |
1.125 |
1.350 |
1.575 |
1.800 |
2.025 |
2.250 |
2.475 |
2.700 |
