Doing the math, I think this is correct
Volume of a bowling ball is 267.947 cubic inches
Volume of finger holes calculation:
Radius of 31/32 finger hole is 31/64 or 0.474 inches
Maximum finger hole depth is 4.5 inches
Volume of cylinder V = π r squared h
Just google volume of cylinder and all you need to do is put in numbers:
At 4.5 inches a finger hole takes out 3.31719 cubic inches
Double this for two finger holes little more than 6.6 cubic inches.
6.6/267.947 = 0.0246% of the volume of the bowling ball is removed with two finger holes drilled to 4.5 inches.
A 14.0 pound ball has 224 ounces
224 X 0.0246% = 5.5 ounces
So a 14.0 pound ball, with 2 finger holes drilled 4.5 inches will end up being 13 pounds 11.5 ounces
A 15.0 pound ball has 240 ounces
240 X 0.0246% = 5.9
rounding that up to 6.0 ounce
A 15 pound ball with 2 finger holes drilled to 4.5 inches would end up 14 lbs 11 ounces
Of course since the weight block is more dense, what balled is drilled, and what layout will change how much of the heavier weight block is removed, so the above is only an estimate.
Why did I do this math?
I have one ball, which despite being a 14 lb ball, just feels heavier than my other 14 lbs balls.
So was thinking about just having really deep finger holes drilled.
I should probably weight it my other 14 lbs stuff to compare first.
The ball came at 14.4 ounce of of box
My other 14 pound balls: once came in at 14.1 out of back. The others were plugged, formerly had thumb holes - so those are lighter.
