How to taper thumb hole?

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fc3
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How to taper thumb hole?

Post by fc3 »

I would like to know how to taper a thumb hole what is the procedure to do it?
Any input would help, thanks!
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Re: How to taper thumb hole?

Post by StrikeTheory »

Any reason you would want to taper a hole to be wider at the top? You would technically be creating additional reverse pitch by coning out the hole.

If you are meaning beveling the top of it, you use a bevel sander, and bevel knife to shape the hole to fit the bowler. Each one is going to be different.
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Re: How to taper thumb hole?

Post by Fitdocsr »

I measure the thumb in 3 segments usually. Drill the appropriate size and depth for each segment then smooth the transistions with bevel sander.

Having the hole small at the bottom helps eliminate knuckling.

There are some other threads on here already about this subject.
Search for T.O.P.S or tapered oval, tiered oval etc
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Re: How to taper thumb hole?

Post by Mo Pinel »

Fitdocsr wrote:I measure the thumb in 3 segments usually. Drill the appropriate size and depth for each segment then smooth the transistions with bevel sander.

Having the hole small at the bottom helps eliminate knuckling.

There are some other threads on here already about this subject.
Search for T.O.P.S or tapered oval, tiered oval etc
Well put!
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Re: How to taper thumb hole?

Post by RevZiLLa »

A tapered and well fit thumb hole is a thing of beauty. The only down side is for people who gain and lose weight easily. Your thumb size changes more up high than at the tip. Often the narrow part of the thumb hole still fits, but the top part is too large and tape is needed. When the tape is inserted, it makes the narrow part of the hole too tight and you can't get all the way in. experimenting with short pieces of tape.
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Re: How to taper thumb hole?

Post by Mo Pinel »

RevZiLLa wrote:A tapered and well fit thumb hole is a thing of beauty. The only down side is for people who gain and lose weight easily. Your thumb size changes more up high than at the tip. Often the narrow part of the thumb hole still fits, but the top part is too large and tape is needed. When the tape is inserted, it makes the narrow part of the hole too tight and you can't get all the way in. experimenting with short pieces of tape.
With your thumb, I consider you an expert.
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Re: How to taper thumb hole?

Post by glssmn2001 »

Fitdocsr wrote:I measure the thumb in 3 segments usually. Drill the appropriate size and depth for each segment then smooth the transistions with bevel sander.
This is how we do my thumb holes with the exception that I smooth out the transitions by hand. I will have to say that it took us a couple of times to perfect the transitions to match my thumb taper and length.
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Re: How to taper thumb hole?

Post by fc3 »

Thank guys got it , this site is amazing
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Re: How to taper thumb hole?

Post by JohnP »

Contour makes a tapered thumb sleeve, see link below, in both smooth and in a power release grip that has a "bump" in it (I don't like these). The main "knock" on sleeves is that they are vinyl rather than urethane and have a different feel. I use them myself and size it so I can use a Magic Carpet in the back and at least one piece of white tape in the front of the hole. So very little of my thumb actually touches the vinyl. -- JohnP

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Re: How to taper thumb hole?

Post by brunswickroller »

there has got to be a way to make a custom mold of your thumb and then produce exact fitting slugs from it time and time again, I don't mean copying a existing thumbhole because many of us can't get one perfect to begin with anyways, I mean actually using your thumb to make a perfect mold, sort of something like this:

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make one of your thumb when you haven't bowled in a week(never happens for me lol), one for when your thumb is average(say after 1 game in league) and one when you have swelled alot(10 games of bowling), use switch grip for everything and you are in thumb heaven

is this too much to ask for? :mrgreen:
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Re: How to taper thumb hole?

Post by fufu »

Fitdocsr wrote:I measure the thumb in 3 segments usually. Drill the appropriate size and depth for each segment then smooth the transistions with bevel sander.

Having the hole small at the bottom helps eliminate knuckling.

There are some other threads on here already about this subject.
Search for T.O.P.S or tapered oval, tiered oval etc
Where do you take measurements at? tip middle and base?
http://www.rotogrip.com" onclick="window.open(this.href);return false;
https://www.facebook.com/Round-Holes-No ... 602077080/" onclick="window.open(this.href);return false;
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Re: How to taper thumb hole?

Post by Fitdocsr »

Yes. The smallest (bottom) cut goes just above the nail.
Measure from base of thumb down to get depth of middle cut.
Just above the nail where the thumb gets larger.
You may not need a third measurement if the person doesn't have taper at the base joint.
I've found you need to subtract 1/8 or 3/16 from the depth bc when you smooth the translations it opens up.
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