Billiard Basic - Bank

When the cue ball hit the object ball and bounce the object ball off one or more rails then into a pocket, you’ve just pulled off a bank shot. The basic technique for aiming bank shots is to first assume that the ball will rebound at the same angle that it hits the cushion. This can be used to estimate the angle; however, pool tables bank shorter than a mirrored rebound angle. Making banks seems easy if an adjustment is made for the shortened bank angle. Unfortunately it is not that simple. The path of the banked ball can actually curve after the ball hits the rail. Any spin in the vertical axis (forward or backward) will cause the ball to curve after striking the rail. The amount of curve is dependent on the ratio of spin to the velocity of the ball. The higher the spin in relation to velocity, the more the ball curves. Note that what is meant by forward spin here means any rotation forward, and rolling is a rotation forward. Backward spin on an object ball is negligible and can only be caused by spin transfer. You can demonstrate what backward spin does by hitting the cue ball into the rail with draw spin. This shot is useful when kicking at balls. Banks are also be affected by English. The same angle bank with the object ball further from the rail and the same speed stroke misses the pocket. The friction of the table causes the object ball to start rolling causing the ball to curve forward after hitting the rail.

Judging bank shots is very difficult because of the number of variables affecting the rebound angle. You can simplify this by removing some of the variables from the shot. If you hit banks firmly removing most of the curvature caused by the object ball rolling.