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Author Topic: Method to check mismarked CG in symmetrical ball?  (Read 2366 times)

Asura

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Method to check mismarked CG in symmetrical ball?
« on: February 20, 2008, 12:22:56 AM »
Anyone care to share any method to check whether a symmetrical ball has mismarked CG? Can we use a dodo scale to find the actual CG ? How?

Thank you
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bluerrpilot

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Re: Method to check mismarked CG in symmetrical ball?
« Reply #1 on: February 20, 2008, 09:51:05 AM »
With the marked cg at the top, the scale should remain balanced regardless of which way you position the ball.
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tenpinspro

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Re: Method to check mismarked CG in symmetrical ball?
« Reply #2 on: February 21, 2008, 12:13:53 PM »
quote:
Anyone care to share any method to check whether a symmetrical ball has mismarked CG? Can we use a dodo scale to find the actual CG ? How?

Thank you


Hey Asura,

Yes, we can use a dodo scale to help find true cg.  A generic rule of thumb on an undrilled ball is one inch of shift will equal one ounce of imbalance for a ball with 3 ounces of top.

Based on this, "t" up your ball at the marked cg and weigh it.  Then reverse your lines in any direction needed to get the scale to read at zero.

For example: If you "t" it up on marked cg and now have one ounce of positive side weight, I'd draw my next line one inch to the left and re-weigh it.  Keep doing this until you get the scale to read at zero.  Use the same method for your vertical weight (finger/thumb) as well.  Hope this helps some....
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Rick Leong - Ten Pins Pro Shop
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Rick Leong - Ten Pins Pro Shop
Co-Founder - Tag Team Coaching
"El" Presidente of the Legion

T-GOD

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Re: Method to check mismarked CG in symmetrical ball?
« Reply #3 on: February 21, 2008, 05:29:59 PM »
quote:
A generic rule of thumb on an undrilled ball is one inch of shift will equal one ounce of imbalance for a ball with 3 ounces of top.
Actually that is true for a ball with 4 oz. top.

Just do what bear said. Here's the link... http://www.lane1bowling.com/tech/cg.html

This works on all balls, not just symmetrical cores. You can use this method to find the ending CG also. Instead of starting near the label or punch mark, start halfway between the original CG and your PAP for balls with 3 oz. or more starting top weight.

For ball with less than 3 oz. starting top, draw the first line using your VAL, then follow the rest of the steps to find the ending CG of the ball. =:^D
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Asura

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Re: Method to check mismarked CG in symmetrical ball?
« Reply #4 on: February 21, 2008, 07:31:21 PM »
ok, Thank you guys!

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tenpinspro

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Re: Method to check mismarked CG in symmetrical ball?
« Reply #5 on: February 22, 2008, 02:56:16 AM »
quote:
Actually that is true for a ball with 4 oz. top


Thanks T...I was guestimating.....
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Rick Leong - Ten Pins Pro Shop
Tag Team Coaching - Co-Founder
"El" Presidente of the Legion

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Rick Leong - Ten Pins Pro Shop
Co-Founder - Tag Team Coaching
"El" Presidente of the Legion

T-GOD

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Re: Method to check mismarked CG in symmetrical ball?
« Reply #6 on: February 22, 2008, 07:43:37 AM »
No problemo. That's the good ole Bill Taylor working on that one. =:^D
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Asura

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Re: Method to check mismarked CG in symmetrical ball?
« Reply #7 on: February 23, 2008, 08:10:42 AM »
Hi again, actually I have a Secret Agent with 3" pin to CG with 3.76oz of topwt. After several failed attempt at laying out the ball (all the layouts have more than 2.5oz of +ve sideweight) I suspected that the must be something wrong with the CG marking.

Using you guys' opinions, I tried using the dodo scale as suggested in Lane 1 site. Result: the actual CG was 2 3/4 inch to the right of the marked CG and 2 1/4" from the pin.

Later I tried laying out the ball and managed to get the layout that I want. There was 7/8 excess +ve sideweight that I eliminate by drilling a balance hole.

So again, thank you guys.
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T-GOD

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Re: Method to check mismarked CG in symmetrical ball?
« Reply #8 on: February 23, 2008, 09:51:47 AM »
The DODO is King..!! Glad things worked out for you Asura. =:^D
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