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 Post subject: How do you figure out symmetrical ball layouts
 Posted: Thu Feb 01, 2018 3:56 am Post Number: #1 Post
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How do you figure out symmetrical ball layouts. There are formulas for figuring out layouts for asymmetrical balls on the wiki page. How can I go about figuring out layouts for symmetrical ball cores.

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Average THS: 209
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Axis Rotation: 40*
Axis Tilt: 30*
PAP: 4 7/16" <, up 7/8"


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 Post subject: Re: How do you figure out symmetrical ball layouts
 Posted: Thu Feb 01, 2018 5:16 am Post Number: #2 Post
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Figure the asymmetrical benchmark then add 5* to the drilling angle and substract 5* to the val angle.

Example:
Asymmetrical Benchmark 90 totals (2:1 ratio) 60 x 4 x 30
Symmetrical Benchmark would be 65 x 4 x 25

Keep in mind pin to pap distances behave differently from asymmetrical to symmetrical.
http://wiki.bowlingchat.net/wiki/index. ... echart.JPG


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 Post subject: Re: How do you figure out symmetrical ball layouts
 Posted: Thu Feb 01, 2018 6:23 pm Post Number: #3 Post
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TonyPR wrote:
Figure the asymmetrical benchmark then add 5* to the drilling angle and substract 5* to the val angle.

Example:
Asymmetrical Benchmark 90 totals (2:1 ratio) 60 x 4 x 30
Symmetrical Benchmark would be 65 x 4 x 25

Keep in mind pin to pap distances behave differently from asymmetrical to symmetrical.
http://wiki.bowlingchat.net/wiki/index. ... echart.JPG



Okay, that makes sense. What do I do if my ratio is not 2:1. I have high axis tilt at 30* and low rotation at 40*. Following the ratio chart, my ratio should be 1:1.75. My dual angle sweet spot is 80*. Do I figure out what my ratio is based of the 1:1.75 ratio. If so my ratio equation for my benchmark would be dual angle sweet spot divided by my ratio.

Benchmark asymmetrical would be 35 x 4 x 45
Benchmark symmetrical would be 40 x 4 x 40?

Am I right in thinking this?

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Left handed
Speed 18.5 off my hand
Average THS: 209
Average on Sport: 191
Rev Rate: 407
Axis Rotation: 40*
Axis Tilt: 30*
PAP: 4 7/16" <, up 7/8"


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 Post subject: Re: How do you figure out symmetrical ball layouts
 Posted: Thu Feb 01, 2018 8:43 pm Post Number: #4 Post
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1:1.75@80º would be 30x4x50
1 + 1.75 = 2.75
80/2.75 = 29 (round to 30º drilling angle)
80 - 30 = 50º VAL angle

The drilling angle on symms should be calculated to be legal, but allow enough static thumb/positive for a balance hole if you need one after rolling the ball on a fresh pattern. Long pin-CG is very helpful here.

I agree with the 4" pin, but not the 1:1.75 ratio; it's too low for a symm layout IMO.
You would be better off with an Asymm with PSA value higher .015 in that case.

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 Post subject: Re: How do you figure out symmetrical ball layouts
 Posted: Thu Feb 01, 2018 11:01 pm Post Number: #5 Post
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snick wrote:
1:1.75@80º would be 30x4x50
1 + 1.75 = 2.75
80/2.75 = 29 (round to 30º drilling angle)
80 - 30 = 50º VAL angle

The drilling angle on symms should be calculated to be legal, but allow enough static thumb/positive for a balance hole if you need one after rolling the ball on a fresh pattern. Long pin-CG is very helpful here.

I agree with the 4" pin, but not the 1:1.75 ratio; it's too low for a symm layout IMO.
You would be better off with an Asymm with PSA value higher .015 in that case.


So you think that symmetrical cores would not fit in my arsenal.

_________________
Left handed
Speed 18.5 off my hand
Average THS: 209
Average on Sport: 191
Rev Rate: 407
Axis Rotation: 40*
Axis Tilt: 30*
PAP: 4 7/16" <, up 7/8"


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 Post subject: Re: How do you figure out symmetrical ball layouts
 Posted: Fri Feb 02, 2018 1:37 am Post Number: #6 Post
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kzues765 wrote:
How do you figure out symmetrical ball layouts. There are formulas for figuring out layouts for asymmetrical balls on the wiki page. How can I go about figuring out layouts for symmetrical ball cores.

As Tony has already explained -5 from the VAL and +5 to the Drilling angle from the Asymmetrical layout to find the Symmetrical layout Target. Then you adjust the Pin to PAP.

When I figure the Basic Symmetrical arsenal deriving it from the Asym layouts I list the Drilling angle to the Cg.
This is to position the Cg for balance hole use.

To do this I model the derived Symmetrical as figured and see where the PSA needs to be.
Then I figure out where a balance hole will be needed to get it as close to the Target as possible.
That is what snick was getting at when he mentioned the Target drilling angle for you being too low for Symmetricals. You can only pull the PSA so far from the thumb with a balance hole. Its not that you Can't use Symmetricals you just have to realize that you will have better control of the Drilling angle with Asyms. Symmetricals will rely on balance holes and surface for you.

I will go through the excercise of figuring out the Basic arsenal layouts for both Asyms and Syms.
Sweetspot 80* total, 1:2.25 Ratio Your totals and ratio are lowered because of being left handed.

Totally Strong ....... 20-5.5-40 P3
Midlane ............... 15-5.25-45 P3
Benchmark .......... 25-5-55 P3 pin in the Middle finger
Long and Strong ... 45-4.25-55 P2.5 Pin in the Ring finger
Control ................ 25-4.5-75 P3

Symmetrical Layouts (derived layout from Asym) (Drilling angle to the Cg for balance hole placement)
Totally Strong ....... 25-3-35 ..................... Double Thumb
Midlane ............... 20-3-40 ......................
Benchmark .......... 30-3-50 ..................... 65-3-50 Balance hole 2" below midline on the VAL
Long and Strong ... 50-4-50 .....................70-3.5-50 P3
Control ................ 35-4-70 .....................70-4-70 Balance hole 2" below midline on the VAL

The Midlane was left blank intentionally, you need an Asym for that one like snick had mentioned.
You could use a Double thumb layout with 360 grit surface for a Midlane reaction.

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 Post subject: Re: How do you figure out symmetrical ball layouts
 Posted: Fri Feb 02, 2018 4:48 pm Post Number: #7 Post
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For symmetrical balls I use the old pin to PAP and pin to cg system to locate the PAP for the layout. The pin to PAP determines the percentage of the potential flare that is used and whether the ball hooks earlier or later. The pin to cg determines the horizontal cg location for static weights and potential use of a balance hole. After the PAP is located the angle to the VAL is used the same as in the dual angle system, primarily setting the pin height. If you have an Armadillo the PAP is very simple to locate. -- JohnP


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