Bowling Evolution Forum

after reading s2dio's "let's make holes in stuff" post that is about ball drillings and teaches people to drill a bowling ball using arcs I am going to do a guide on dual angle drilllings.

I used to hear things like "cg kicked out at 90°" or "MB at 45°" and would get confused but I looked into dual angle drillings and now understand what they are talking about.

How to actually lay out the ball
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I will explain about your angles later on in the post first off which way to do it.

This will be for a right hander and a layout of 4" with 55° cg and 35° VAL... this layout will be relatively skid flipy but still recover enough in the midlane.

Step 1
add in your reference line going through cg (or mb if thats the only thing there)


Step 2
from the centre of your Pin create your angle from the reference line
this will give you your cg angle





Step 3
along the second line you made measure your pin distance (mine is 4") and this spot will become your positive axis point


Step 4
measure your PAP angle from your cg angle line as 0 (when you create this line it will make a z like shape if it makes a c like shape you made your pap angle the wrong way round) and this will create your VAL (vertical axis line)


Step 5
Reverse your PAP to find your centre of grip (I am going to use 4" across and 1/2" down)


Step 6
use your grip specs to measure up and drill

How do these effect your balls reaction
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Cg angle

The Cg angle helps determine how your ball will roll such as whether it is going to skid alot or transition early

PAP or VAL angle
basically the same effect as the Cg angle to help determine how your ball will roll.

Pin length
This is the biggie in your layout it will determine THE MOST.
Your Pin length determines when your ball will hook how much it will flare and how early it hooks.

Laying it out how your want
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CG angle
Your basic rule of thumb is the smaller the angle the earlier it effects the balls roll, although it doesn't effect the balls roll by too much it still does.
For a steady roll (good for sport conditions) I personally find it best to use angles of between 25° and 45°
For a skid flipy roll (good for house shots because carry is your main factor) anywhere above 55° is good
The 90° drilling is very versatile and is very useful on many patterns.


VAL angle
Your basic rule of thumb is the larger your angle the earlier it will roll
For a steady roll I find it best to go between the 25° and 45° range.
it is hard to create a skid flipy roll from changing Val it is best to change both VAL and CG

Pin length
Longer pin length later it rolls and less it flares
I CANNOT TELL YOU WHAT YOUR PIN LENGTH SHOULD BE AS IT DEPENDS ON HOW YOU BOWL