Definitions for "Balance Hole"
Keywords:  abc, pba, tune, drilled, gripping
An extra hole not used for gripping purposes, drilled to keep the ball within legal specifications as regards to weight balance.
As a general rule, if you take a bowling ball and place the label in front of you and then exactly dissect the ball into two equal halfs, a right and left side, the gross weight of each half would be the same. However, if you dissect the ball off center, a greater portion of the weight block will be on one side of the ball, possibly making that half of the ball too heavy vis-a-vis the other half; also, modern high tech balls and their asymmetrical cores can be drilled in such a manner as to be in violation of the maximum tolerances allowed by the ABC for side to side weight (which is a one ounce differential); to get the ball back to legal compliance an extra, non-gripping hole may be drilled to remove the excess weight. This extra hole is the balance hole. The balance hole can also be used to increase or decrease a ball's reaction and/or to fine tune a more subtle change in ball reaction.
(n.) The place in a combination wheel where material has been eliminated to provide an equal distribution of weight over the entire wheel relative to the axis. Source: Lock Industry Standards and Training (LIST) Council