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Author Topic: Really Dumb XH Questions  (Read 2248 times)

RSalas

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Really Dumb XH Questions
« on: June 28, 2003, 12:18:39 AM »
For you experienced ball-drillers out there, when you need to drill an extra hole to take out a specific amount of weight, how do you decide upon the dimensions of the hole?  Do you use a standard hole width or depth?  Also, do you treat the ball as having a uniform density, or do you take into account such ball construction factors as coverstock thickness and proximity of the core to the surface of the ball?

Last question (for now):  Do you ever pitch the extra hole, and if so, under what circumstances do you do this?

Thanks.
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Re-Evolution

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Re: Really Dumb XH Questions
« Reply #1 on: June 28, 2003, 04:16:47 PM »
Not an expert but this is what I know about balance holes.

Generally find the place for it buy drawing a line from grip center through the CG to the VAL and place it at the intersection of this line and the VAL. This can be altered to some degree by moving the hole up and down the VAL, as long as finger and thumb weights stay legal, this is for fine tuning, thumb weight earlier, finger later.

The deeper the hole the more delayed the reaction, due to the fact the drilling deep raises the RG factor of the ball.

The hole can't be larger than 1 1/4" in diameter.

The actual diameter and depth of the hole is determined by the static balance of the ball which is measured on a balance scale by putting the ball in different positions. After determining imbalance the driller can determine how large and deep the hole needs to be. A large factor in this is the amount of predrilled top weight when going with an aggressive drill pattern.

High Rev bowlers will generally want a smaller deeper hole.

I believe this is all correct but like I said not an expert. Anyone have corrections and/or additions?
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STORMIN1
F5 TORNADO IS COMING THROUGH, WILL THE 10 PIN SURVIVE AGAIN!
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Re-Evolution

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Re: Really Dumb XH Questions
« Reply #2 on: June 29, 2003, 02:18:56 AM »
king of the mill; balance holes do affect the RG of the ball if the hole is deep enough to reach the core. The core is denser than the cover therefore the more core you remove the lighter the center of the ball is and RG is a measurement of the more center heavy the ball the lower the RG. If you would like to test this, do a test on a "determinator" with a ball that the balance hole reaches the core and one that it does not with the same ball and overall static weight the deeper hole will have a higher RG, granted the difference will vary depending on how deep into the core you drill and if you barely touch the core it will lower the RG. Regardless the RG is affected wether it goes up or down.
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STORMIN1
F5 TORNADO IS COMING THROUGH, WILL THE 10 PIN SURVIVE AGAIN!

Edited on 6/29/2003 2:30 AM

Edited on 6/29/2003 2:32 AM
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B Pirnie

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Re: Really Dumb XH Questions
« Reply #3 on: June 29, 2003, 09:45:28 AM »
This page will give you ebonite's view of balance holes
 http://www.ebonite.com/techcenter/balanceholes.php
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Re-Evolution

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Re: Really Dumb XH Questions
« Reply #4 on: June 29, 2003, 10:36:55 AM »
king of the mill

RG is one of the major factors in determining how long it takes for a ball to reach its Positive Spin Axis, therefore RG is affected as I said. But I guess if you say I am still wrong then I guess Storm is wrong too.
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STORMIN1
F5 TORNADO IS COMING THROUGH, WILL THE 10 PIN SURVIVE AGAIN!
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