Balancing

? Balancing a Bowling Ball — Norms to Follow & Dodo Scale

When a bowling ball is drilled, holes for the fingers and thumb remove material and shift its center of gravity (CG).
To ensure the ball remains legal and properly balanced, pro shops measure the ball’s static balance using a dodo scale and follow USBC balance norms.

⚖️ 1. Norms to Follow — USBC Static Balance Rules

The United States Bowling Congress (USBC) sets the official balance limits that all drilled bowling balls must meet.

? USBC Legal Limits (Current as of 2025):

Type of Weight Imbalance	Maximum Allowed Difference
Top or Bottom Weight	3 ounces maximum
Side Weight	3 ounce maximum
Finger or Thumb Weight	3 ounce maximum

⚠️ Weight holes (balance holes) are no longer allowed — since August 1, 2020.
Only gripping holes (fingers and thumb) are permitted.

? Static Weights Explained

Term	Description	Ball Motion Effect
Top Weight	Weight above the ball’s center line	Helps delay hook (more length)
Bottom Weight	Weight below the ball’s center line	Promotes earlier roll
Side Weight	Difference between left/right halves	Affects flare and backend motion
Finger/Thumb Weight	Difference between upper/lower halves	Impacts roll and reaction smoothness

Norm: Keep these weights within limits while achieving desired ball reaction.
Excessive imbalance makes the ball illegal and unpredictable.

⚙️ 2. Using a Dodo Scale to Measure Balance

The dodo scale is a specialized tool used by pro shops to measure static imbalances (top, bottom, side, finger, and thumb weight) in ounces.

? Parts of a Dodo Scale

Base Platform: Holds the ball in place.
Balancing Arm / Beam: Works like a scale arm with weights to measure imbalance.
Pivot Point / Knife Edge: It allows the arm to move freely.
Indicator Dial / Counterweights: Shows weight difference in ounces.

? How to Use the Dodo Scale (Step-by-Step)

Find the Center of Gravity (CG):
- Marked on the ball by the manufacturer.
- It’s the point used as the reference for all balance measurements.
Measure Side Weight:
- Place the ball on the dodo scale so the CG is aligned horizontally (left to right).
- Rotate the ball 90°.
- The scale shows the difference between the right and left halves (in ounces).
- Must be ≤ 3 oz.
Measure Finger/Thumb Weight:
- Rotate the ball so the CG is aligned vertically (top to bottom through the gripping holes).
- The reading shows weight difference between finger and thumb sides.
- Must be ≤ 3 oz.
Measure Top/Bottom Weight:
- Place the ball with the CG on top and measure the vertical imbalance.
- Reading must be ≤ 3 oz.
Adjust If Needed:
- If imbalance exceeds the limit, adjust drilling depth or plug/redrill holes to bring the ball within legal range.

? Norms When Using a Dodo Scale

Step	Norm / Best Practice
Before Drilling	Record factory top weight and CG location.
After Drilling	Check all three balances (top, side, finger/thumb).
Adjustment	Stay comfortably below USBC max limits (not exactly at them).
Documentation	Record final readings for reference.
Verification	Test-roll to confirm expected ball motion.

⚙️ 3. Why Balancing Matters

Proper balance ensures that:

The ball rolls evenly and predictably.
The core orientation performs as designed.
The ball is USBC-legal for competition.

Unbalanced or illegal balls can:

React unpredictably on the lane.
Violate competition standards.
Affect the bowler’s release or control.

✅ Summary — Norms to Follow

Category	Norm / Standard	Measured By
Static Balance	3 oz top, 3 oz side, 3 oz finger/thumb	Dodo Scale
Dynamic Balance	Proper core layout and reaction shape	Dual Angle / CAD tools
Physical Fit	Comfortable grip and pitches	Fit tools / Pro fitting
No Balance Holes	Only finger & thumb holes allowed	USBC Rule
Check After Drilling	Verify legality before use	Dodo Scale Measurement

? In Short

“Balancing a bowling ball” means making sure it meets USBC static balance limits and rolls as intended.
The dodo scale is the key tool used to measure and confirm those weight differences after drilling.