"Offset" thumb/fingers

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SaltandPepa
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"Offset" thumb/fingers

Post by SaltandPepa »

Hello,

What components changed when I drilled my 35 degree thumb of standard T-line like you would do it normally and then moved fingers right and drilled them so that RF cut line was touching center T-line then I've marked bridge 1/4'' and then drilled RF. Span is the same distance like it would be from standard T-line.

What exactly changed in thumb (oval angle, pitches ) and what in fingers ?

If somebody could simulate drilling and give me some answers I highly appreciate that.

Full span
RF: 4'', 1/4'' reverse, 1/4'' left
MF: 4 1/16'', 3/8'' reverse, 7/16'' right
Thumb:
47/64'' pivot drill
35degree@9/64(x=0.115;Y=0.081)
1/8'' forward, 1/8'' left

Many thanks
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VLe
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Re: "Offset" thumb/fingers

Post by VLe »

SaltandPepa wrote: What exactly changed in thumb (oval angle, pitches ) and what in fingers ?
What you are doing here is that you are turning the thumb centerline. Similar thing that for example in the "45degree thumb drilling"-method but not as radical. I suppose you are left handed? I also suppose that you drill the finger pitches based on the line that you draw from the thumb center to this "new bridge".

The result is (if I understood correctly) that if you take the drilled ball and measure the pitches you will have the finger pitches exactly as before. Your thumb oval angle is a little bit bigger. Thumb has little bit more left pitch and little less forward. Take your current ball and draw a normal thumb-to-bridge -line. Then draw another line from thumb center to another side of your RF hole, .125" from the RF hole (the transported new bridge) and measure the angle between these two lines. With this angle you can calculate the pitch changes either with some trigonometry or you can use the fingerpitch calculator that I have uploaded to another thread (viewtopic.php?f=7&t=12631). Or just take your ball and measure the pitches directly from it. :)
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PAP 4 3/8" x 0"
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VLe
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Re: "Offset" thumb/fingers

Post by VLe »

Actually I'm not sure whether you meant that the new T-line goes through your "previous" MF hole or to the other side of it. Anyway if you measure the angle you can calculate the change in pitches.

I made a very rough estimation on the angle and here is the results for example:

With transported angle of 16,88 degrees, your thumb pitches:
.156" left, .083" forward
oval angle 51,88 degrees

With angle of 8,44:
.142" left, .105" forward
oval angle 43,44 degrees
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Right Handed
PAP 4 3/8" x 0"
60* rotation
17.5* tilt
320-360 rev rate
17mph off hand
SaltandPepa
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Re: "Offset" thumb/fingers

Post by SaltandPepa »

The drilling was done by mistake, drilling at -10 degrees in garage :) but actual feel in the thumb inside the hole and at the lanes is better then normal, so I am curius what exactly changed ?..

Right handed player
The thumb is drilled from normal T-line, 35degrees, 1/8 forward, 1/8 left, but the fingers are drilled from parallel line right to the T-line, moved away aprox. max 1/2''.
Like you would have 2 T-line drawn next to each other with distance 1/2'' apart..from one you drill thumb from other fingers.

You are wright when you say that this is going towards 45 angle drilling method and I think that maybe this is what is creating better feel in the thumb hole.

I think just by looking at the hole from above that the oval angle is slightly decreased actualy to about 20-25 degrees and that that is what is bugging me.

I would like to try something again tomorrow and my plan is to drill the ball like this.

Draw standard T-line and drill fringers normally from it.
Then on the right side from that line at 55 (orange line in the picture) draw another line and make it my thumb line. I will rotate the ball on that 55 degrees line and drill the thumb with 1/8 forward, 1/8" left and 0 degrees oval angle.

Will this work ? :)
Many thanks for looking up.
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snick
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Re: "Offset" thumb/fingers

Post by snick »

It looks to me like your pitch angles will be rotated 55º, and the center of the thumbhole will be offset to the left of the T-grip.
I would draw the 55º thumb-line from the center of the thumbhole on the T-grip line and start with 3/16 left pitch, and tweak it from there.

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SaltandPepa
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Re: "Offset" thumb/fingers

Post by SaltandPepa »

Yes you are correct I did a bad drawing here and did it from cut/span line when it should have been from center of the thumb hole like you did it.
My plan is to get pitches drilled from 55 degree line and get 35 oval angle.
I will cut in half measurements off my thumb drill bit 47/64'' and mark that spot as a center of the thumb hole..... from there I will draw a line at 55 deegres. That should be correct.

Thanks for that tip. :)

Why would you go with 3/16" left ? I was planing to go with my actual pitches 1/8'' forward and 1/8'' left. I think if I go just left with the pitches I will be more close to what I would be with standard T-grip.

Don't know but this might be very good way to drill a bowl. I mean If you put your hand on the top of this picture fingers in the place where the holes are-like you would grab a ball and then you move your thumb back and forth you will see that it goes in the direction of 55 degree line and oposite to that if you move it left and right it goes along 35 oval angle line...at least for me. :)
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snick
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Re: "Offset" thumb/fingers

Post by snick »

1/8 left and 1/8 forward points your thumb 45º to the left of the T-grip.
The angled thumb line rotates this angle clockwise.
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VLe
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Re: "Offset" thumb/fingers

Post by VLe »

I think that the explaining of the subject is a little complicated here. When you say about turning the ball, use the angle from the basic t-line to the new centerline for thumb. In the picture you are turning the ball 35degrees from the t-line. I told you wrong pitches at the first post because I didnt understood the explanation correctly.

As far as i understand it now, you are using "35degree thumb drilling". If you want to drill those 1/8" left' 1/8" forward pitches "turned 35 degrees" and using only the finger t-line your pitches would be: .174" forward and .031" left.

Normal 1/8" left and 1/8" forward is a hole pitched .177" at 45degree angle from the t-line counterclockwise. If you use those pitches with 45 degree thumb drilling you are actually pitching the hole only forward (.177") based on the finger t-line.
Right Handed
PAP 4 3/8" x 0"
60* rotation
17.5* tilt
320-360 rev rate
17mph off hand
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