Three-times-angle rule (draw)Ball first, with draw — the cue ball turns 3 times the cut angle

Difficulty FREE🖨 Drill cards✓ Exam on this system PRO📐 Measure on your table PRO
Reference positionBall fraction 1/2Deflection angle (°) 90

Spinside 0 · low

1/2

Ball fraction1/2

SpeedNot specified

⧉ Project on table▭ Show on wall

Cut angle 30° → the cue ball turns 90° from the cue line.

A cue ball struck with good draw comes back after hitting ball 2. If the cut angle is between 0° and 40° (3/8 ball and fuller), the final direction of the cue ball departs from the cue line by three times the cut angle. The line of impact (the line joining the centers of the two balls) divides this total angle into three: there is 1 part between the cue line and the line of impact, and 2 parts between the line of impact and the final direction.

When? In ball-first shots, to estimate where the cue ball will go after ball 2 with draw (coming back), i.e. from which direction it will go to the 1st cushion; especially in positions that call for a full ball and a draw shot.

✓ 6/6 examples verified by the formula
Calculate
Deflection angle = 3 × cut angle (cut angle 0°–40°)
Ball fraction
Deflection angle (°)90
  1. Deflection angle (3 × cut angle)90
  2. Deflection angle (°)90
✓ Example: Reference position: half ball

Voice coach

PRO

The voice coach is part of the Pro and Club plans.

See plans

Watch outThe values are a theoretical reference; they may vary by a few degrees with the table, the balls and the stroke. The diagrams show not the curve of the cue ball but only its final direction.

Watch outSide spin is not taken into account.

Rate this content
Your rating
Was this helpful?

Comments

Loading comments…