Bowling Ball Drilling Information

When drilling holes in a bowling ball, you must take several factors into consideration. Holes make a ball lighter, which can affect balance, and the span and pitch of the holes can affect comfort. You should also plug old holes.

  1. Finger and Thumb Weight

    • Drilling a thumb hole closer to the label creates negative weight, making the ball roll earlier for a straighter shot. Drilling finger holes closer to the label makes a positive weight, which enhances the ball's hook, delaying the roll.

    Top and Bottom Weight

    • Drilling holes to give a ball a higher top weight will cause it to go farther before hooking. A ball with higher bottom weight will change direction earlier.

    Span

    • The span measures the distance from the thumb hole to the finger holes. If the span measures too long or too short, it will not fit the bowler's hand.

    Pitch

    • A forward pitch allows you to hold the ball longer because the thumb hole angles toward your palm. A reverse or back pitch angles the hole away from your palm, so your thumb exits the hole sooner.

    Plug

    • A plastic plug fills a previously drilled finger or thumb hole. The plastic hardens to make a smooth surface, so you can drill holes in a different location.