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Brian Pursel:Ebonite Product Manager

I have had numerous questions regarding the positive axis point and its relation to the release and to ball drilling. Most all drilling instructions denote a certain pin distance from the positive axis point to achieve a desired reaction. Without knowing a bowler“s positive axis point, the driller cannot predict a ball reaction with certainty, even with general knowledge of the physical attributes of the bowler (axis tilt, axis rotation, rev rate, and ball speed) and the lane conditions.

Every ball released rotates on an axis. It is a direct result of the release and swing plane of the bowler. The axis is an imaginary line through the center of the ball, extending from one side to the other. The two points on the ball“s surface through which this line extends are the negative axis point (NAP) and the positive axis point (PAP). For righthanded bowlers, this would be to the right side of the grip. For lefthanded bowlers, the PAP would be on the left side of the grip. The PAP is on the side of the ball opposite the ball track. The ball track for righthanders would be to the left of the fingers, the ball track for the lefthanders would be to the right of the fingers. The exception to this would be the backup bowler (reverse hook).

Righthanded hook bowlers release the ball with a wrist rotation in a counter-clockwise direction. The fingers exit the ball anywhere from 5:30 (behind the ball) to 3:00 (on the right side of the ball). This causes the ball to revolve from right to left, creating a hook from right to left. A righthander who throws a reverse hook rotates the hand in the opposite direction, turning clockwise. The fingers exit the ball between 6:30 and 9:00, causing a left to right rotation. This will result in a left to right hook. The ball track (where the ball comes into contact with the lane surface) will be to the right of the grip. This will make the reverse hook bowler“s ball track look similar to the lefthanded bowler“s ball track. The PAP of the righthanded reverse hook bowler will on the left side of the grip, the lefthanded reverse hook bowler“s PAP on the right side of the grip.

It is easiest to locate the PAP from a lower flaring ball. I would suggest a spare ball. Clean off the ball with a towel, removing all of the oil rings. Find the part of the lane where there is oil (usually around the 4th arrow) and throw the ball down the lane with your normal release. When the ball comes back, there will be an oil ring. This is your ball track. Trace the ball track with a wax pencil to make it easier to locate. Place the ball in a ball cup (ashtray, etc.) with the ball track side of the ball down. The PAP will be the point that is equidistant from each point of the ball track. Use a tape measure from several points of the ball track until you find the spot that is the same distance from all points of the ball track. This point will be your PAP.

The easiest method of finding your PAP is to visit your local Striking Effects Pro Shop, or other IBPSIA certified pro shops. They will own a ball spinner. Using the spinner, place the ball with the track side down. Turn on the spinner and look for the ball track outline to rotate smoothly, not wavering up and down. If it is wavering, stop the ball spinner and readjust the way the ball is sitting in the spinner cup. Once the ball track is constant, press a wax pencil at the top of the rotating ball. It will center up onto a point. This center is the PAP. To verify the location of the PAP, place a piece of thumb tape on this spot and throw a shot down the lane. This spot should stay still throughout the first 25 feet. For low flare balls (those with weaker core designs), this spot will stay still longer. Higher flare balls (those with stronger core designs) will cause the tape to begin wobbling sooner. This is why I suggest to use lower flaring balls (ideally your spare ball) to locate your PAP.

To measure the location of the PAP, you will need to be able to find the center of your span. This will be half the distance from the front edge of the thumbhole to the front edge of the fingers. From the center of span, draw a perpendicular line (lets call this line ”Horizontal‘) to the same side of the ball that the PAP is located on. More times than not, this line will not intersect directly with the PAP. You will need to draw a line vertically up (or down in some cases) to the PAP. This ”Vertical‘ line is perpendicular to the ”Horizontal‘ line. This will give you two measurements, horizontal and vertical, to accurately locate the PAP from the center of your span.

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