Predictability of reaction shape for Double Thumb Drilling?

Ask Mo Pinel and the bowling industry's best your general questions, and get straight answers.

Moderators: Mo Pinel, purduepaul, MathIsTruth, ballspinner

Forum rules
Ask Mo Pinel and the bowling industry's best your questions, and get straight answers.
This forum is moderated exclusively by Mo & Friends.
Locked
User avatar
M4R10
Member
Member
Posts: 76
Joined: October 1st, 2010, 11:12 pm
Positive Axis Point: 5-1/8 over, 0 up
Speed: 17 mph off hand
Rev Rate: 390
Axis Tilt: 5-10
Axis Rotation: ~55
Heavy Oil Ball: AMF Mega Recovery, Layout 45* x 3-1/4 x 30*
Medium Oil Ball: Track 715C, Layout 75* x 2-1/8 x 60* P2 Hole
Light Oil Ball: Brunswick Slingshot, Layout 70* x 4-1/4 x 45* DT hole
Preferred Company: whatever fits my need
Location: Hamburg, Germany

Predictability of reaction shape for Double Thumb Drilling?

Post by M4R10 »

First off, I DO understand the technical idea of the double thumb drilling. Raising the RG of the PSA as much as possible by drilling two large holes close to the PSA which increases overall and intermediate differential.

So we KNOW the ball will have maximized core dynamics but what about the reaction shape?

The following line of thoughts seems worth discussing:
- Pin distance (4") and VAL angle (30*) seem to be fixed on the first look
- Drilling Angle seems to be the only variable to that layout and depends on the bowler's PAP
- Distance from "Pin to Spin Line" to PAP will vary depending on PAP
- Angle ratios will vary depending on PAP
- Angle sum might or might not be within my sweetspot range

This leads me to think that different bowlers will get different reaction shapes out of the same ball with DT drilling. Shorter PAP (e.g. 3.5" over) will have sooner and smoother transitions where longer PAP (e.g. 6" over) will have later and sharper transitions.

Edit:
After re-reading the DT instructions I found Recommended pin distance should be between 3.5" and 5.5".

So the pin distance is not fixed. I guess I am not the only one who has been mislead into thinking this. All the instructions on finding the drilling angle use the 4 inch pin distance and the other pins distances are only mentioned once.

What about the VAL angle? Does this HAVE to be 30* or would 20* or 40* work as well? I imagine as long as the PSA ends up between the thumb and balance holes it should be OK. It might even be a good idea to use a 3.5" pin distance because the pin will be further away from the fingers for many bowlers. Drilling the finger holes close to the pin raises the low RG. Avoiding to do so while at the same time maximizing the high RG (PSA) will increase differential, or not?
User avatar
Mo Pinel
Rest In Peace
Rest In Peace
Posts: 10054
Joined: January 26th, 2010, 6:10 pm
Preferred Company: MoRich, & now RADICAL BT
Location: Richmond, VA

Re: Predictability of reaction shape for Double Thumb Drilling?

Post by Mo Pinel »

M4R10 wrote:First off, I DO understand the technical idea of the double thumb drilling. Raising the RG of the PSA as much as possible by drilling two large holes close to the PSA which increases overall and intermediate differential.

So we KNOW the ball will have maximized core dynamics but what about the reaction shape?

The following line of thoughts seems worth discussing:
- Pin distance (4") and VAL angle (30*) seem to be fixed on the first look
- Drilling Angle seems to be the only variable to that layout and depends on the bowler's PAP
- Distance from "Pin to Spin Line" to PAP will vary depending on PAP
- Angle ratios will vary depending on PAP
- Angle sum might or might not be within my sweetspot range

This leads me to think that different bowlers will get different reaction shapes out of the same ball with DT drilling. Shorter PAP (e.g. 3.5" over) will have sooner and smoother transitions where longer PAP (e.g. 6" over) will have later and sharper transitions.

Edit:
After re-reading the DT instructions I found Recommended pin distance should be between 3.5" and 5.5".

So the pin distance is not fixed. I guess I am not the only one who has been mislead into thinking this. All the instructions on finding the drilling angle use the 4 inch pin distance and the other pins distances are only mentioned once.

What about the VAL angle? Does this HAVE to be 30* or would 20* or 40* work as well? I imagine as long as the PSA ends up between the thumb and balance holes it should be OK. It might even be a good idea to use a 3.5" pin distance because the pin will be further away from the fingers for many bowlers. Drilling the finger holes close to the pin raises the low RG. Avoiding to do so while at the same time maximizing the high RG (PSA) will increase differential, or not?

I don't know where all these variables come from. MathIsTruth and I did ALL the research on the "Double Thumb" technique. Purduepaul verified our findings empirically. There is a reason for everything. It's on the home page of the MoRich website as written by MoRich. In this case, we are the authority. The variable in this is that the ball reaction is so strong that it tends to change the PAP for a vast majority of bowlers. Also, the low RG axis tends to move towards the VAL when this drilling is used. The chosen pin to PAP distance of 4" ends up with a real pin to PAP distance of about 3 3/8" with the new PAP (for this layout only). The chosen VAL angle of 30* usually ends up at 20*. The variable of the drilling angle, depending on the bowler's PAP, is designed to locate the PSA exactly between the thumb hole and the balance hole. There are variations that can be used by moving the PSA, only. Moving the PSA to the balance hole location will decrease the skid slightly. Moving the PSA to the middle of the thumb hole will slightly increase the skid. Those are the only variables I suggest you use. Keeping the pin to PAP distance and the VAL angle fixed is my recommendation. If you want a different reaction, use a different layout. The purpose of the DT drilling is to maximize the int. diff., the total diff., and the diff. ratio of the drilled ball.

AMEN, because it may have sounded like a sermon.
Rest In Peace (1942-2021)
User avatar
M4R10
Member
Member
Posts: 76
Joined: October 1st, 2010, 11:12 pm
Positive Axis Point: 5-1/8 over, 0 up
Speed: 17 mph off hand
Rev Rate: 390
Axis Tilt: 5-10
Axis Rotation: ~55
Heavy Oil Ball: AMF Mega Recovery, Layout 45* x 3-1/4 x 30*
Medium Oil Ball: Track 715C, Layout 75* x 2-1/8 x 60* P2 Hole
Light Oil Ball: Brunswick Slingshot, Layout 70* x 4-1/4 x 45* DT hole
Preferred Company: whatever fits my need
Location: Hamburg, Germany

Re: Predictability of reaction shape for Double Thumb Drilling?

Post by M4R10 »

Mo, thanks a lot for the insight. I did not take into account that the strength of the ball might acutally make the ball flare so much right out of the hand that it will have a different PAP. This is were theory meets reality...

One reason that got me thinking about this was that for my PAP the DT layout would be 70x4x30 which is very close to my benchmark layout with a P4 hole. So I was wondering if a layout with a smaller angle sum and P4 hole might transition faster. But thinking about it the answer has to be "no" because the maximum core dynamics are achieved by the DT drilling and there is no possibility that any other layout will make that ball transition faster.

Probably my initial question about the "reaction shape" is a bit absolete since the ball will be so strong that it will be hard to tell the difference. At least if the drilling was applied on a ball with already strong dynamics before drilling.

Again, thanks for your patience discussing all our questions!
User avatar
Laniarty
Member
Member
Posts: 109
Joined: July 27th, 2010, 10:54 pm
Preferred Company: Storm

Re: Predictability of reaction shape for Double Thumb Drilling?

Post by Laniarty »

Would changing the pin to pap distance make a double thumb drilling more useable? For instance 60 x 2 1/2 x 30? So the Drilling and Val angles are still strong, however the pin distance stunts a lot of the excessive flare and reduces some of the strength of the reaction.
Right handed ~450 rpm 16 mph 12° tilt 65° rotation
Virtual Gravity Nano - 35x4.5x45
Critical Theory - 70x4x40
Prodigy - 60x3.5x30
607A - 85x2.5x35
Slingshot - 60x5x40
User avatar
M4R10
Member
Member
Posts: 76
Joined: October 1st, 2010, 11:12 pm
Positive Axis Point: 5-1/8 over, 0 up
Speed: 17 mph off hand
Rev Rate: 390
Axis Tilt: 5-10
Axis Rotation: ~55
Heavy Oil Ball: AMF Mega Recovery, Layout 45* x 3-1/4 x 30*
Medium Oil Ball: Track 715C, Layout 75* x 2-1/8 x 60* P2 Hole
Light Oil Ball: Brunswick Slingshot, Layout 70* x 4-1/4 x 45* DT hole
Preferred Company: whatever fits my need
Location: Hamburg, Germany

Re: Predictability of reaction shape for Double Thumb Drilling?

Post by M4R10 »

I think modifiying a layout that is intended to maximize total and intermediate diffs with a flare reducing pin distance is a bit like buying a race horse when you need a working horse to plough your field. If you don't need a race horse why buy one on the first place? If you don't need maximum ball reaction...

Actually it's not a DT drilling any more if you use a less flaring pin. What you are suggesting sounds a bit like a control layout with a P4 hole which already is a bit absurd, isn't it?
User avatar
Mo Pinel
Rest In Peace
Rest In Peace
Posts: 10054
Joined: January 26th, 2010, 6:10 pm
Preferred Company: MoRich, & now RADICAL BT
Location: Richmond, VA

Re: Predictability of reaction shape for Double Thumb Drilling?

Post by Mo Pinel »

Laniarty wrote:Would changing the pin to pap distance make a double thumb drilling more useable? For instance 60 x 2 1/2 x 30? So the Drilling and Val angles are still strong, however the pin distance stunts a lot of the excessive flare and reduces some of the strength of the reaction.
Whats wrong with that is that the pin to PAP distance might become as little as 1", which will cause the PAP to lock on the pin early, killing the flare. Not recommended! I recommend using only the adjustments that I described.
Rest In Peace (1942-2021)
User avatar
kellytehuna
Senior Member
Senior Member
Posts: 2891
Joined: January 18th, 2010, 11:11 pm
THS Average: 195
Positive Axis Point: 3.75", 1" up
Speed: 18
Rev Rate: 480
Axis Tilt: 17
Axis Rotation: 40
Heavy Oil Ball: Morich DestroyR
Medium Oil Ball: Morich Perpetual Motion
Light Oil Ball: Morich Mojave
Preferred Company: Morich
Location: Hazard, KY

Re: Predictability of reaction shape for Double Thumb Drilling?

Post by kellytehuna »

M4R10 wrote:Actually it's not a DT drilling any more if you use a less flaring pin. What you are suggesting sounds a bit like a control layout with a P4 hole which already is a bit absurd, isn't it?
Couldn't have said it better!
Father, Husband, Bowler, Web developer

15lb Morich DestroyR, Mania, Perpetual Motion, Craze, Frenzy, Mojave
15lb Radical Yeti
15lb Brunswick Slingshot, Avalanche Urethane

Highest score: 279
Highest series: 818
Adrenaline
Member
Member
Posts: 215
Joined: January 28th, 2010, 10:22 am
Positive Axis Point: 5>1^
Speed: 15.5
Rev Rate: 230
Axis Tilt: 10
Axis Rotation: 70
Medium Oil Ball: Pink Panther
Location: Sacramento, CA

Re: Predictability of reaction shape for Double Thumb Drilling?

Post by Adrenaline »

M4R10 wrote: Edit:
After re-reading the DT instructions I found Recommended pin distance should be between 3.5" and 5.5".

So the pin distance is not fixed. I guess I am not the only one who has been mislead into thinking this.
No one else has corrected you yet, so just to clear any confusion others might have from reading your post...
The pin distance IS fixed and is ALWAYS 4".

The 3.5-5.5" comment you read, is the recommended Pin to CG distance. This is for choosing a ball that will be compatible with the layout. Short pin outs, make it impossible to use the Double Thumb Layout. In order to stay legal, you need a bunch of thumb weight, so that you can drill the X-hole deep enough to be effective.
User avatar
M4R10
Member
Member
Posts: 76
Joined: October 1st, 2010, 11:12 pm
Positive Axis Point: 5-1/8 over, 0 up
Speed: 17 mph off hand
Rev Rate: 390
Axis Tilt: 5-10
Axis Rotation: ~55
Heavy Oil Ball: AMF Mega Recovery, Layout 45* x 3-1/4 x 30*
Medium Oil Ball: Track 715C, Layout 75* x 2-1/8 x 60* P2 Hole
Light Oil Ball: Brunswick Slingshot, Layout 70* x 4-1/4 x 45* DT hole
Preferred Company: whatever fits my need
Location: Hamburg, Germany

Re: Predictability of reaction shape for Double Thumb Drilling?

Post by M4R10 »

Adrenaline, I really appreciate you pointing this out. I hadn't noticed my misunderstanding yet. :oops:

Probably it happened in the first playe because I was reading so many posts about layouts over the last weeks and there "pin distance" is mostly used for "pin to PAP distance" and not for "pin to CG distance" (a.ka. "pin out")...

I think, since this site is all about precision and education we all should try to adhere to precise terminology as well. There shouldn't be different terms used for the same thing or vice versa. This a great example why.

Again, thanks!
User avatar
Mo Pinel
Rest In Peace
Rest In Peace
Posts: 10054
Joined: January 26th, 2010, 6:10 pm
Preferred Company: MoRich, & now RADICAL BT
Location: Richmond, VA

Re: Predictability of reaction shape for Double Thumb Drilling?

Post by Mo Pinel »

M4R10 wrote:Adrenaline, I really appreciate you pointing this out. I hadn't noticed my misunderstanding yet. :oops:

Probably it happened in the first playe because I was reading so many posts about layouts over the last weeks and there "pin distance" is mostly used for "pin to PAP distance" and not for "pin to CG distance" (a.ka. "pin out")...

I think, since this site is all about precision and education we all should try to adhere to precise terminology as well. There shouldn't be different terms used for the same thing or vice versa. This a great example why.

Again, thanks!
AMEN!
Rest In Peace (1942-2021)
Locked