question about finger hole drill depth??? help needed

[JAnderson]

Also I believe it lowers the flare potential a little bit, depending on the pin location. Drilling the fingers deeper make the core shorter, and lowers the differential.

It depends on whether or not any core material is removed when the finger and thumb holes are drilled and the resulting core shape/mass distribution. The same is true for pins above or below fingers. Generally speaking, I agree that pins below the fingers tend to help create earlier hook, but if no core material is removed either way, pin below or pin above will have the same effect. Pancake "cores" are a good example, but not the only example.

The angle created in relation to how you deliver the ball is EXTREMELY important

There are different schools of thought on this. The USBC and Brunswick maintain that surface preparation and pin placement are the two biggest non-bowling/non-lane-condition factors on ball movement and that changes in layout cause a much smaller change in ball movement. My experiments back up the surface argument. You can take a ball with a layout that is "strong and early", polish it up with turtle wax (clogs the pores) and (all other factors equal) make it go stick straight. Take a ball with a "length" or weak layout and sand it down to 80 grit and (all other factors being equal) it is going to hook at your shoe laces. I have yet to see a change in ball layout - however drastic - create such large changes in ball movement.

[playbowl]

JAnderson you wrote:

The USBC and Brunswick maintain that surface preparation and pin placement are the two biggest non-bowling/non-lane-condition factors on ball movement and that changes in layout cause a much smaller change in ball movement.

Absolutely - See the USBC Ball Motion study for the effect each has on overall motion. Great information.
Stremmel/Ridenour

[JAnderson]

The bowl.com site seems to be unreachable for me today, so I can't verify the link to the study, but I believe it is http://www.bowl.com/articleView.aspx?i=14185

There's an introduction and overview that was written before the study:
http://www.bowlingdigital.com/bowl/node/3473