BallReviews

General Category => Drilling & Layouts => Topic started by: Inferno_256 on December 19, 2005, 07:10:09 AM

Title: Oval thumb hole
Post by: Inferno_256 on December 19, 2005, 07:10:09 AM
how do you make an oval thumb hole?
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Brunswick kicks buttocks
Title: Re: Oval thumb hole
Post by: JamesCube on December 19, 2005, 03:30:49 PM
After you drill a hole, you move the jig a little bit to shave a little off of one side of the hole, thereby creating an oval.

A lot of people think the drill bit wobbles.  How the hell would the bit wobble?
Title: Re: Oval thumb hole
Post by: scotts33 on December 19, 2005, 06:31:50 PM
http://www.ebonite.com/tradesection/comercial_prod_catalog/detail.php?PRKey=25

This is what my pro uses to drill everything including oval thumb holes.  Love the fit.  Notice this ain't no cheap mil/drill....also why I don't mind paying good $ for a great job done by a master fitter/layout expert/driller.  


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Scott

Title: Re: Oval thumb hole
Post by: Inferno_256 on December 19, 2005, 06:49:27 PM
If you were to drill an oval wouldn't you need to use a smaller drill bit than your regular size circular hole because drilling it twice would make the hole too big. If so approximately how much smaller.
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Brunswick kicks buttocks
Title: Re: Oval thumb hole
Post by: solid9 on January 01, 2006, 04:35:08 PM
Inventory!!!!
Title: Re: Oval thumb hole
Post by: DukeHarding on January 01, 2006, 04:35:20 PM
quote:
stupid question, but why don't you just use an oval thumb insert....


I've always used an oval thumb insert...

Always wondered the same thing?
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Duke Harding
++++++++++++++++++++++++++++++++++++++++++++

Bowling Coaches Web Site Link (http://"http://www.bowlingcoach.com/")

"Anyone who stops learning is old, whether at twenty  or eighty.
Anyone who keeps learning stays young.
The greatest thing in life  is to keep your mind young." -- Henry Ford
Title: Re: Oval thumb hole
Post by: charlesrob on January 01, 2006, 07:17:36 PM
Use a caliper to measure the front-to-back width of the thumb for the thin part of an oval hole. Use a regular round fitting to determine the side-to-side width. Skill is needed to figure at what angle to drill the oval, or measure an old ball with an oval insert to determine the correct angle to drill the oval hole. Using a drill jig that has an X-Y axis is best. Using trigonometric functions, you can figure how far and in what directions to lay out the two hole drill pattern.

As to why drill instead of an oval insert? Feel for some people. Shop inventory for others.
Top weight has to be higher in the ball. When you drill for inserts you use a big hole. Oversize thumbs like mine require a 1-3/8" hole almost 3" deep for an insert. When I drill it is only 1-1/8" by 1" oval  2-3/4" deep. If you want to keep top weight (and I do ) this requires a ball with high top weight which is not always easy to find or stock.
Title: Re: Oval thumb hole
Post by: bowlio on January 02, 2006, 01:03:41 PM
i have had my oval thum now for over 2 years and i have never ever drilled 2 holes into my thum
what i doo is drill the hole to the size of my thum then i use a grease pencil and wet my thum and put the grease on my thum then i put my thum into the ball so that i use a scraper to get the size i need if it dont quite fit i sand out my thum
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stats:
speed: 18-19 mph
rev: hard
track: high
high game: 286
best series: 698

I love Storm and Storm loves me
Title: Re: Oval thumb hole
Post by: DukeHarding on January 02, 2006, 11:21:24 PM
quote:
Any of you folks who turn the ball a bit early, beware of a snug oval.


Snug oval thumb will sure make you NOT turn the ball early.
My driller put me in an oval thumb 10 years ago because I had that nasty habit.

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Duke Harding
++++++++++++++++++++++++++++++++++++++++++++

Bowling Coaches Web Site Link (http://"http://www.bowlingcoach.com/")

"Anyone who stops learning is old, whether at twenty  or eighty.
Anyone who keeps learning stays young.
The greatest thing in life  is to keep your mind young." -- Henry Ford
Title: Re: Oval thumb hole
Post by: Sawuser on January 02, 2006, 11:24:53 PM
quote:
Any of you folks who turn the ball a bit early, beware of a snug oval.


That's probably why I use round hole!
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Wayne
Hardcore FOS

Rom 2:2 Professing themselves to be wise, they became fools


Title: Re: Oval thumb hole
Post by: Gallo81 on January 19, 2006, 01:03:58 PM
I remember that it supposed to be some kind of rule or scale to make an oval thumb with a Jigg X and Y, is there anyone who has this scale? it supposed to have the angle and the movments in .25 or more to X and Y.

I mean that I saw in a ProShop, my driller used to have a table with all the Trigonometrical Functions.
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GALLO
Relax, is just a Game.

Edited on 1/19/2006 2:12 PM

Edited on 1/19/2006 8:09 PM
Title: Re: Oval thumb hole
Post by: JohnP on January 19, 2006, 07:17:15 PM
Gallo -- Go to the Jayhawk site (link below) and download the PDF file labeled Oval Drilling Guide.  That may or may not help.  --  JohnP

 http://www.jayhawkbowling.com/Pro_s_Corner/Pro_Shop_Forms/forms.html