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General Category => Drilling & Layouts => Topic started by: 86camaroman on October 20, 2011, 01:16:03 AM

Title: how to drill oval thumb holes.
Post by: 86camaroman on October 20, 2011, 01:16:03 AM

Can someone explain to me how to drill oval thumb holes. Would like to start doing them Thanks very much

Title: Re: how to drill oval thumb holes.
Post by: Mattski on October 20, 2011, 09:18:38 AM

There are many different ways, although they are limited as to what drill press you have.

Title: Re: how to drill oval thumb holes.
Post by: 86camaroman on October 20, 2011, 09:27:00 AM

Please explain do you just drill your hole then change pitches or what

Title: Re: how to drill oval thumb holes.
Post by: Pinhammer on October 20, 2011, 09:36:23 AM

you move table left or right and forward or reverse depending on RH or LH but you need a good jig or mill to do it correctly.  If you have a milling table with your jig it would be easy with practice.  there is a chart on JayHawks site that has the correct movement measurments.

Roger Carroll
Pinnacle Pro Shop
Clarksville, TN
http://www.pinnaclebowl.com/ProShop/proshop_main.html

Title: Re: how to drill oval thumb holes.
Post by: Pinhammer on October 20, 2011, 09:37:27 AM

Boy I need to quit using my phone to answer these thing because it doesn't capitalize worth a crap.

Roger Carroll
Pinnacle Pro Shop
Clarksville, TN
http://www.pinnaclebowl.com/ProShop/proshop_main.html

Title: Re: how to drill oval thumb holes.
Post by: 86camaroman on October 20, 2011, 10:06:01 AM

I cant find it can you post a link to it.

Title: Re: how to drill oval thumb holes.
Post by: lane1lover on November 08, 2011, 11:33:22 PM

it is a very simple geometry calculation, first thing you need to know you 'angle' of oval,  it is the horizontal line vs the direction of the widest part of your thumb, then, use some measuring tools to check the height and width of your thumb, check the different, use the height as the first Pilot hole this is the first hole with the actual span length with.

 

then this is the latest tricks:

 

minus the width and the height, it is the baseline, use this to plot the sin and cos with the 'angle' of  oval.  cos is the way to get the horizontal move, sin is the way to get the vertical move

 

you then will get the actual total vertical and horizontal move that you need with the drilled pilot hole, divided it into two part, then. reset the digital meter of your drill mill to zero, . use at least 2 moves. up + left, then down + right  (right hand, left hand reverse) with the above calculation result.

 

 I used this method even in all 3 finger holes for lots of customer and all feel very happy with that accuracy, however, because of some thumb shape issue,  sometime need to use garbage ball to test drill first

 

 

 

 

 

 

 

 

Edited by lane1lover on 11/9/2011 at 0:34 AM

Title: Re: how to drill oval thumb holes.
Post by: lane1lover on November 08, 2011, 11:37:22 PM

forgot to tell that I used this method to drill any angle, you can imagine that, i was challenged by other proshop operator that how to drill any angle between and i was sure win for any competitor. for your info, the Jayhawk drilling program also using this method to calculate the same thing.

Title: Re: how to drill oval thumb holes.
Post by: LuckyLefty on November 09, 2011, 07:24:43 AM

1/8 X 1/8   is 45 degrees.  Everything is a variation on that.  Less verticle = a smaller angle.  More vertical is a bigger angle.

 

Regards,

 

Luckylefty

PS that can all be seen in the charts.

It takes Courage to have Faith, and Faith to have Courage.

James M. McCurley, New Orleans, Louisiana