Symmetric vs. Asymmetric Layouts
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Author:  JimJimTheGreat [ Fri Feb 11, 2011 12:31 am ]
Post subject:  Symmetric vs. Asymmetric Layouts

Can you use the same angles for symm as you do for asymm or is there a special rule that you have to follow?
For example: would a 45x45 @5in for an asymm ball give the same general reaction on a symm ball or would it be different?
I ask this because on a symm ball the box layouts are all different than the asymm for the same box layout reactions.

Author:  JustinWi [ Fri Feb 11, 2011 11:23 am ]
Post subject:  Re: Symmetric vs. Asymmetric Layouts

You have to have a completely different approach to drilling symmetrical vs. asymmetrical balls. The main reason is differences in flare. You also can get a much more precise result out of an asymmetric. Here are the main points:

3 3/8" pin to PAP is maximum flare, longer(towards 6.75") and shorter(towards 0") reduce flare.
Drilling angle is completely irrelevant to final reaction.
The after drilling PSA is located in or very close the the thumb.

0-2.25" is minimum flare, 2.25" to 6.75" is maximum flare. But, pins closer to 2.25" retain axis rotation longer, pins closer to 6.75" result in forward roll.
After drilling the PSA remains very close the the marked PSA.
Any "asymmetrical" ball with less than a .008" intermediate differential should be treated as a symmetrical ball, as it will still spin to the thumb.

Those are the primary differences, when choosing a layout you really have to think about what the mass properties will be after drilling on a symmetrical. The asymmetric will be much more predictable, and adhere to the initial layout.

Author:  Bob Michalojko [ Fri Feb 11, 2011 10:22 pm ]
Post subject:  Re: Symmetric vs. Asymmetric Layouts

Excellent summary of the importances & differences between symm's & asymm's. I'm printing it out & putting it up on my pro shop wall to refer back to. Good job!

Author:  JustinWi [ Sat Feb 12, 2011 12:42 pm ]
Post subject:  Re: Symmetric vs. Asymmetric Layouts

Glad it helped you out a bit Bob.

It is admittedly a summary and there are more variables, but those are the major bullet points to consider.

Author:  JimJimTheGreat [ Sat Feb 12, 2011 12:46 pm ]
Post subject:  Re: Symmetric vs. Asymmetric Layouts

Thank's for the info.

Author:  JCumbie [ Tue Apr 10, 2012 12:35 pm ]
Post subject:  Re: Symmetric vs. Asymmetric Layouts

Not sure if this helps at all, but...

From my visits with Mo Pinel, when he suggests benchmark angles for his pupils, he generally adjusts for asymm by removing 5 degrees from the drilling angle, adding 5 to the val angle, and adding about a half inch pin to pap.

Symm benchmark - 55 x 4 1/4 x 55
Asymm benchmark - 50 x 4 3/4 x 60

That may be too general to apply all the time, but he did the same thing for me, my dad, and my wife during our initial visit with him. ( -5 x +1/2" x +5 for asymm's)

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