How to tune Rack Attack Pearl's reaction

Which layout is right for me?

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TonyPR
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How to tune Rack Attack Pearl's reaction

Post by TonyPR »

Hello, I recently started playing thumbless (2 handed approach) and got a Rack Attack Pearl drilled. My initial intentions were 80* x 4 1/2" x 40* which would be a benchmark layout for my current specs. Unfortunately my friend (pro shop operator) got a bit confused when laying out my PAP and the ball came out 5 1/4" Pin to PAP (which is alright for me) and a very small 20* VAL angle. I tried the ball on a 41' THS with backends that are famous for hooking a lot, and the reaction was too much flip for me. While I know the ball's design is skid flip and I got an undrilled Grease Monkey I intend to drill for control to complement the Rack Attack Pearl, the reaction to dry was too jumpy for my slow speed/high revs and I had a hard time keeping it right of the head pin (even swinging it). I am still developing my two handed footwork and have made some improvements speedwise but have not yet reached my goal of 17 mph in the monitor. Currently I don't play Sport conditions so we are talking ball reaction for THS only.

Got the ball sanded with 1000 then 2000 on a spinner and will try it soon, hope this helps to tame the back end. Will report back on this.

I had been reading the symmetric drilling instructions and noticed the pin on my ball is over the RF. Balance hole was drilled to help open the Drilling Angle but after re-reading Blueprint's track flare study which proves Drilling angle has little to no effect in symmetric balls, I think there probably would have been better places to drill the balance hole.

What would be my best option if surface adjustment alone does not get me the reaction I want? Please don't say increase my speed, I am working on that...
1. Plug the balance hole and drill it some other place? Where?
2. Plug the whole thing and redrill with original intended layout?

!!! Bowl 2 handed with thumb in to have more options with balance holes. (being sarcastic but seriously considering it jejeje).

Please advise.
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Re: How to tune Rack Attack Pearl's reaction

Post by Mo Pinel »

TonyPR wrote:Hello, I recently started playing thumbless (2 handed approach) and got a Rack Attack Pearl drilled. My initial intentions were 80* x 4 1/2" x 40* which would be a benchmark layout for my current specs. Unfortunately my friend (pro shop operator) got a bit confused when laying out my PAP and the ball came out 5 1/4" Pin to PAP (which is alright for me) and a very small 20* VAL angle. I tried the ball on a 41' THS with backends that are famous for hooking a lot, and the reaction was too much flip for me. While I know the ball's design is skid flip and I got an undrilled Grease Monkey I intend to drill for control to complement the Rack Attack Pearl, the reaction to dry was too jumpy for my slow speed/high revs and I had a hard time keeping it right of the head pin (even swinging it). I am still developing my two handed footwork and have made some improvements speedwise but have not yet reached my goal of 17 mph in the monitor. Currently I don't play Sport conditions so we are talking ball reaction for THS only.

Got the ball sanded with 1000 then 2000 on a spinner and will try it soon, hope this helps to tame the back end. Will report back on this.

I had been reading the symmetric drilling instructions and noticed the pin on my ball is over the RF. Balance hole was drilled to help open the Drilling Angle but after re-reading Blueprint's track flare study which proves Drilling angle has little to no effect in symmetric balls, I think there probably would have been better places to drill the balance hole.

What would be my best option if surface adjustment alone does not get me the reaction I want? Please don't say increase my speed, I am working on that...
1. Plug the balance hole and drill it some other place? Where?
2. Plug the whole thing and redrill with original intended layout?

!!! Bowl 2 handed with thumb in to have more options with balance holes. (being sarcastic but seriously considering it jejeje).

Please advise.

My suggestion is that a balance hole in the PAP, taking it to 3/4 oz of negative side should help a bunch.
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Re: How to tune Rack Attack Pearl's reaction

Post by TonyPR »

Thanks a lot Mo, I will try that balance hole. Love the color of this ball and I was surprised by how much backend reaction one can get from the coverstock. Would it have been better if I would have gotten my intended VAL angle originally or is pin (up, down, right of RF, etc) and cg (for balance hole placement) location and pin to pap distance more important in symmetrics, I noticed you don't mention VAL angle recommendations (except for the double thumb) in your new symmetrical drilling instructions. Also, do all the layouts in those instructions apply to thumbless bowlers too?
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Re: How to tune Rack Attack Pearl's reaction

Post by DarkHorse »

Understand something about the Blueprint Track Flare Study - it never said the actual Drilling Angle has no effect in symmetrics, it said that swinging the CG as a means to determine the Drilling Angle has no effect.

Drilling Angle will absolutely have an effect on symmetric ball motion, but you establish the Drilling Angle by balance hole placement, for a no-thumb layout, not by swinging the CG left or right.

Hope that helps.
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Re: How to tune Rack Attack Pearl's reaction

Post by Mo Pinel »

DarkHorse wrote:Understand something about the Blueprint Track Flare Study - it never said the actual Drilling Angle has no effect in symmetrics, it said that swinging the CG as a means to determine the Drilling Angle has no effect.

Drilling Angle will absolutely have an effect on symmetric ball motion, but you establish the Drilling Angle by balance hole placement, for a no-thumb layout, not by swinging the CG left or right.

Hope that helps.
Balance hole size and location is the most critcal factor to ball motion on a symmetrical ball because it moves the PSA of the drilled ball around so much. On no thumb drillings, the balance hole can cause wild swings in the PSA location because the drilling holes remove so little mass from the ball. I recommend drilling the finger holes at least 3" deep on no thumb balls to help stabilize PSA movements when adding a balance hole. I've been tracking the movement of the PSA on no thumb balls with a DeTerminator to learn more about the PSA movement. No solid determinations, yet. My 13 year old son, Levi, is a no thumb bowler because I wouldn't let him use his thumb when he started. So I get plenty of practice on these layouts.
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Re: How to tune Rack Attack Pearl's reaction

Post by TonyPR »

So Mo, could we expect a symmetric drilling instructions sheet for thumbless balls sometime in the near future?
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Re: How to tune Rack Attack Pearl's reaction

Post by gunso »

Mo Pinel wrote:
Balance hole size and location is the most critcal factor to ball motion on a symmetrical ball because it moves the PSA of the drilled ball around so much. On no thumb drillings, the balance hole can cause wild swings in the PSA location because the drilling holes remove so little mass from the ball. I recommend drilling the finger holes at least 3" deep on no thumb balls to help stabilize PSA movements when adding a balance hole. I've been tracking the movement of the PSA on no thumb balls with a DeTerminator to learn more about the PSA movement. No solid determinations, yet. My 13 year old son, Levi, is a no thumb bowler because I wouldn't let him use his thumb when he started. So I get plenty of practice on these layouts.
when drilling for your son, do you adjust for the difference in val angle since val angles measured to the center of fingers tend to be much larger (30+º) than measured to grip center of thumbin bowlers?
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Re: How to tune Rack Attack Pearl's reaction

Post by TonyPR »

Gunso, I see no difference, for VAL angle you need Pin to PAP an Vertical Axis Line, centerline is the same no matter if the ball is thumbless or not, if thumbless you just draw the centerline down from the grip center and VAL would be the line that goes through the PAP parallel with that line. Now it is true that thumbless bowlers typically align inserts using this centerline instead of a CLT but centerline is always the same.
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Re: How to tune Rack Attack Pearl's reaction

Post by Mo Pinel »

TonyPR wrote:Gunso, I see no difference, for VAL angle you need Pin to PAP an Vertical Axis Line, centerline is the same no matter if the ball is thumbless or not, if thumbless you just draw the centerline down from the grip center and VAL would be the line that goes through the PAP parallel with that line. Now it is true that thumbless bowlers typically align inserts using this centerline instead of a CLT but centerline is always the same.
Thanks!
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Re: How to tune Rack Attack Pearl's reaction

Post by gunso »

Mo Pinel wrote:
Thanks!
Thanks for claring that up. I distinctly remember reading it somewhere but that must have been the wrong information. I will adjust my notes accordingly :)
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Re: How to tune Rack Attack Pearl's reaction

Post by gunso »

Mo Pinel wrote:
Balance hole size and location is the most critcal factor to ball motion on a symmetrical ball because it moves the PSA of the drilled ball around so much. On no thumb drillings, the balance hole can cause wild swings in the PSA location because the drilling holes remove so little mass from the ball. I recommend drilling the finger holes at least 3" deep on no thumb balls to help stabilize PSA movements when adding a balance hole. I've been tracking the movement of the PSA on no thumb balls with a DeTerminator to learn more about the PSA movement. No solid determinations, yet. My 13 year old son, Levi, is a no thumb bowler because I wouldn't let him use his thumb when he started. So I get plenty of practice on these layouts.
would you be inclined to inform us of some of your favorite balance hole locations for him and what those locations would be useful for? I'm redrilling my whole arsenal this fall and have another thumbless 2hander on my team which I have to think of layouts for. any help on the balance hole locations would be awesome :)
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Re: How to tune Rack Attack Pearl's reaction

Post by TonyPR »

Update: Did not need to plug and redrill the balance hole, surface change did the trick. Ball is 500, Royal Compound, Royal Shine out of box. We applied a 1000 then a 2000 and that really helped to tame the backend reaction. Tried it on a fresh THS 39' and ball was still skid flip but controllable at 14 mph monitor speed, once I get my speed up I will adjust surface accordingly.


Thinking about something like:
85* x 5 1/4" x 55*
or
85* x 5 1/4" x 60*
as a control layout for the Grease Monkey to use it on fresh and then use the Rack Attack Pearl when the lane transitions.
Am I on the right track?
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