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 Post subject: Re: Fun one for you Eric
 Posted: Mon Dec 17, 2018 8:42 pm Post Number: #21 Post
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EricHartwell wrote:
It is not about where the palm is. The ball doesn't know or care if your palm is anywhere or if even you have a palm or not, examples Throbot or E.A.R.L.

It is about the PAP and the initial track.

The grip center is basically the center of removed mass. This the ball does know and care about because it is affecting the physical properties of the ball.

This is an interesting topic and something that needs to be kept in mind. The CAD models used to determine the dual angle methods were done with a thumb hole in mind, I believe. The idea is that the smaller VAL angles cause the thumb hole to be drilled more into the side of the core, thereby making it taller relative to its width, thereby raising the differential of the drilled ball. The bigger VAL angles have the opposite effect, drilling the fingers into the top of the core and the thumb less into the side, reducing the height relative to its width, thereby reducing the diff of the ball.

So with the above information in mind, placing the pin several inches above the fingers will be putting holes in the side of the core, and is probably increasing the diff. This is where a typical drilling would have the thumb hole placed. I would think that placing the pin near the fingers is not advisable, as you wouldn't be able to reliably predict where the Low RG axis moves. I do, however, see that Mo's recommended no thumb layouts does have layouts with the pin near the fingers, so there's likely something I'm missing.

I would expect the Low RG to move away from the fingers. All of the example layouts have the pin up and to the right of the fingers, and in those cases I would expect the Low RG to move up and to the right, lowering the drilling PAP to low RG and thereby the expected flare. Knowing Mo, he factored that into his suggestions.

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 Post subject: Re: Fun one for you Eric
 Posted: Tue Dec 18, 2018 4:46 am Post Number: #22 Post
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This is a super interesting topic and I have been doing empirical research by drilling balls different ways and by asking some key people. As I see it there are two main options:

Use center of bridge as center of grip

Use a regular span (4” for example) and center of grip like a thumb in bowler but do not drill the thumb.

This last method seems to work on Asymms by drilling fingers only 2” deep so they do not affect the core much. It’s basically about positioning an asymmetrical core on your palm in a certain way and not affecting the undrilled numbers much by drilling the fingers at regular depth.

The center of bridge as center of grip version seems to create quite a strong reaction by placing the pin way up and drilling the fingers 3.5” deep not quite where a thumbhole would be but midway between where fingers and a thumb would be on a regular three hole ball and affecting the core shape by drilling deep closer to where a thumb would be as opposed to the other method.

Then we have some symmetrical balls that work by using the center of “span” method drilling fingers 2” deep and not drilling the thumb. I have a Purple Hammer which I sold and came back to me plugged. I drilled fingers where they were 2” deep but didn’t drill the blance hole it had basically where a thumb would be. Pin is close to above and to the side of the rf. About 1/2 away from it and at a 45* angle from it. This isn’t dual angle, it’s just to give you an idea where the pin is at. This ball rolls nice but with very low flare. Reads early and continues great through the pins by throwing it out to around 6 at 40’ on a high volume house shot...

I believe core design is going to have to be considered more rigorously from now on for no thumb drillings.


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 Post subject: Re: Fun one for you Eric
 Posted: Tue Dec 18, 2018 6:58 pm Post Number: #23 Post
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My interest is piqued now. I've been out of the game for about a year now, but I may visit the shop this week and spin a few no thumb balls on the DeTerminator to see where the PSA ended up and where I think the Low RG is. Will report back if anyone is interested.

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 Post subject: Re: Fun one for you Eric
 Posted: Tue Dec 18, 2018 7:21 pm Post Number: #24 Post
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Arkansas wrote:
Will report back if anyone is interested.


I am!

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 Post subject: Re: Fun one for you Eric
 Posted: Tue Dec 18, 2018 7:56 pm Post Number: #25 Post
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Yeees, pleeeease do!


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 Post subject: Re: Fun one for you Eric
 Posted: Wed Dec 19, 2018 1:05 am Post Number: #26 Post
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Looking forward to seeing the DeTerminator results.

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 Post subject: Re: Fun one for you Eric
 Posted: Wed Dec 19, 2018 2:04 am Post Number: #27 Post
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Just drilled a 14 lbs plugged Purple Hammer for the 12 yr old high speed high rpm two hander. Went experimental on this one: X x 1.5 x 55 drilled using center of bridge as center of grip, fingers 3.5” deep.
CG ended up on positive side with 2.5oz of side weight. Mo wrote on his drilling instructions that shorter pin to paps would be used more to play straighter. I know it’s a very low diff core but was just curious as I’ve never seen this done on a Purple Hammer which is a great ball for the sport shot playing rev dominant crew. Will report back.


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 Post subject: Re: Fun one for you Eric
 Posted: Mon Dec 24, 2018 3:05 pm Post Number: #28 Post
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I was able to spin 2 symmetrical balls this weekend. Neither ball had the pin close to the fingers.

I asked that as he drills no-thumb balls in the future that he spin them and send me a picture. The drill angle on the two-tone ball came out to be 125*. It was about 35* higher than where it was anticipated.

Hopefully I can get some more balls spun in the coming weeks.

He also has a copy of Blueprint, so if I get some free time I'm going to go up there and run some simulated drillings through there and report back.


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 Post subject: Re: Fun one for you Eric
 Posted: Mon Dec 24, 2018 5:33 pm Post Number: #29 Post
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You say not the anticipated results. With these being fresh drillings no plugs I was expecting the PSA to show up on the line from the pin through the fingers. If I was to try to predict even closer I would calculate the center of the removed mass producing deviations from the drawn Center of Grip based on the pitches and depth of the drilled fingers.

The more no thumbers I talk to the more disdain for the new rules I hear and complaints about having to plug the balance holes.
An interesting one would be a before and after on a ball that just has the thumb/balance hole plugged.
For this I would expect the PSA to stay close to the original point But I expect the spin time to be longer. An indicator that the PSA is weaker.

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 Post subject: Re: Fun one for you Eric
 Posted: Mon Dec 24, 2018 7:25 pm Post Number: #30 Post
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Same thought on drilling angle being from PAP to pin to finger holes.

Interesting would be to drill a low int diff Asymm like the Kinetic Emerald and drill the fingers shallow (2”) using a 4” span to layout but not drilling the thumb and then do the same layout on an identical ball using the center of bridge to lay it out and then compare spin times and where the psa ends up.

After recording results drill fingers on both balls 3.5” deep and record how spin times and psa locations vary.

Finally do the same experiment on two strong Asymms like a Rip’D or Paradox for example.

Wish I got free balls and a determinator...


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