Important definitions used is this blog.
PAP (positive axis point) - The point on the pocket side of the ball that is at the end of the bowler's axis of rotation upon delivery.
Midlane - This is the middle part of the lane past the heads (1st 20 feet of the lane) and before the backends (last 20 feet of the lane).
The pin in a bowling ball (the colored ½” plug) signifies the center of the core. Besides surface texture it is the single most important factor in determining ball reaction. The distance the pin is from the PAP determines the amount of track flare and energy released which in turn determines how much total hook there is.
Pin Up refers to the pin being located above the fingers holes on your bowling ball.(see picture below for example) The pin could be located above either finger, between the fingers, or anywhere above a line drawn from the top of your finger holes. Depending on your PAP, a pin up drilling can mean a multitude of things. A bowling ball drilled with the pin above the middle finger will react differently than a ball drilled with the pin above the ring finger. Pin up ball drilling will in essence get the ball further down the lane before making its hook motion. This can be enhanced by the distance the pin is above the fingers (the higher up the longer). Most of the ball’s energy will be stored for the midlane and backend of the lane.
Pin Down refers to just the opposite of Pin Up. The pin would be located anywhere below the finger holes.(see picture example below) Pin down bowling balls will tend to start up or get into a roll faster. Pin down drillings can be useful when attacking a longer oilier lane condition where you want the ball to read the lane the soonest. The downfall to this is the ball uses most of its energy in the front portion of the lane and may lose carry potential.
When building your bowling ball arsenal it is always a good idea to have at least one pin-up and at least one pin-down drilled bowling ball. Even better would be to have multiple pin-ups/pin-downs with different surface textures. In my current arsenal I have 2 pin-ups and 2 pin-downs, with one of each at a duller texture and one of each at a shiny texture. With these options there isn’t a lot of conditions I wouldn’t be able to tackle.
|Example of a Pin Up Drilling|
|Example of a Pin Down Drilling|