Drilling is where a bowling ball becomes yours. It is not just punching three holes. The layout, the position of those holes relative to the core and your hand, changes how the ball revs, where it reads the lane, and how strong the backend is. A good drilling makes a ball fit your hand and your game. A bad one wastes a good ball.
Two jobs: fit and reaction
Drilling does two things at once. First, it fits the ball to your hand through the right span and pitches, so you can hold and release it cleanly. Second, it sets the ball reaction through the layout. Fit makes the ball comfortable and repeatable. Layout makes it move the way you want. Both matter, and a good pro shop handles both.
The pin and how it guides layout
Every modern ball has a pin, a small colored dot that marks the top of the core. Where the driller places that pin relative to your hand changes the ball motion. This is the heart of layout, and it is why the same ball can be drilled to behave differently for different bowlers.
Pin up vs pin down
One of the most common layout choices is pin position relative to your fingers.
- Pin up (pin placed above the finger holes) tends to give the ball more length and a stronger, more angular move at the backend. Good when you want the ball to save energy and snap.
- Pin down (pin placed below the finger holes) tends to make the ball read the lane earlier and roll smoother and more controllably, with a more rounded shape.
Neither is better, they are different tools. Pin up for length and pop, pin down for early, smooth control. A good driller picks based on your game and the lanes you bowl.
Dual angle and the rest
Modern layouts use a dual angle system that controls how quickly the ball revs up and how strong and how far down the breakpoint is. The details get technical, but the practical point is simple: tell your pro shop how you bowl and what reaction you want, and a good driller translates that into a layout. You do not need to master the math, you need a driller you trust. Understand what the layout is shaping in our ball motion guide.
Balance holes and current rules
Balance holes, extra holes drilled to adjust the ball static weights, used to be common. The rules have changed, and in sanctioned play balls now generally cannot have a separate balance hole. A good pro shop keeps up with current regulations so your equipment stays legal for league and tournament play. When in doubt, ask your driller before a competition.
Get drilled by a real pro shop
This is not a do-it-yourself job. A reputable pro shop measures your hand, talks through your game, and drills both the fit and the layout to match. The same ball drilled well outperforms the same ball drilled poorly by a wide margin. Build the relationship with a driller who watches you bowl. It pays off for years. Pair the right cover from our coverstock guide with the right layout and you have a ball built for your game.
Frequently asked questions
What is pin up vs pin down drilling?
Pin up places the pin above your finger holes and tends to give more length and a stronger, more angular backend. Pin down places it below and tends to make the ball read earlier and roll smoother. Each is a different tool for a different reaction.
What does the pin on a bowling ball do?
The pin marks the top of the core. Its position relative to your hand, set during drilling, controls how the ball revs and where it reads the lane. The layout built around the pin is what shapes your ball motion.
Can a bowling ball have a balance hole?
Rules have changed, and in sanctioned play balls generally can no longer have a separate balance hole. A reputable pro shop stays current on regulations so your equipment is legal for league and tournament play. Ask your driller before competing.
Can I drill my own bowling ball?
It is strongly not recommended. Drilling requires measuring your hand for span and pitch and choosing a layout for the reaction you want. A pro shop does both correctly, and a good drilling makes a big difference in performance.
For the official specifications behind this, check the USBC.
Bottom line
Drilling fits the ball to your hand and shapes how it moves. Understand pin up for length and pin down for control, keep your gear legal, and trust a real pro shop to drill both the fit and the layout. Stay Hungry.
