This is what I found that describes how the thumb offset is layed out.
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Here's how the centerline shift layout is done.
1. Draw the centerline and midline of the persons grip on a ball that fits them very well.
2. Place persons thumb in the ball so that their fingers lay across the finger holes.
3. Take a pencil and draw a line from the center of the finger holes toward the grip midline between your fingers following the angle of the fingers.
You are looking for the angle that the fingers are in reference to their thumb.
4. Now you must take the dimensions form the center point to the two points of the triangle youhave created. These dimensions are what you will use to set up the new ball to be drilled with a CLT Drilling.
5. Create the same lines using the dimensions off the other ball. Also draw a line perpendicularto the new finger centerline. That will help you rotate the grips to the proper angle. The angled line that you have created will be you centerline for drilling the finger holes.
There is many different ways people set up the ball to be drilled. Some drill thumb first others drill fingers first. It doesn’t matter
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6. The angled line that you have created by drawing between the fingers becomes the new centerline for drilling the fingers. Rotate the ball so that the new centerline is straight up anddown when the ball is in the jig. Set your pitches, line-up the bit to your lines and punch the hole.
7. Repeat step 6. For the other finger.
8. Rotate grips to be parallel to the line you drew in step 5.
This grip will help the hand lay a little flatter on the ball and to most people it feels more comfortable
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This is what one person said:
Ok, I have to interject into this topic...
I'm currently running through Ebonite's Powerhouse Pro Shop Training class, taught by Jeff Ussery. Just yesterday, we went over spans, pitches and such, and he stressed that there is no such thing as an 'offset thumb hole'.
See, when you drill a new thumb hole, you just shifted your center line, as well as your mid line. The center line is the line that passes through the middle of the bridge and the center of the thumb hole. Therefore, if you have a ball already drilled, find the center line, then plug and move the thumb hole to the left (or right), you now have a NEW center line, NOT an 'offset thumb hole'. Yes, the hole is now shifted to a different spot, but all that you have done is change the full span for the two fingers.
A center line is a center line, no if's, and's or but's. To say that this isn't true is to pretty much tell Ebonite that they are wrong.
Just thought I might interject my current studies.
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Edited on 1/4/2008 4:34 PM