Author Topic: Drilling Oval (Read 7044 times)

dR3w · « **on:** September 24, 2009, 03:13:30 AM »

Several years ago I purchased a pro shop setup with what I guess is the older version of the dual chamber vacuum jig from innovative. I got some lessons in the basics and have been drilling for myself and close friends mostly. I never really learned how to drill ovals into a thumb slug and was wondering if there was any information/video out there that would be helpful. I have an idea about how to do it, but if anyone could pass on a link or maybe provide a short tutorial I would really appreciate it.

I am guessing that after you drill the hole for the thumb you have to move the pitches both vertically and laterally a certain amount. So I'm guessing that if someones thumb fits in the hole with maybe 45 degrees from the horizontal, you would move the press up 1/32" and left 1/32" and drill. Also doing this at 1/32" down and 1/32" to the right (with the same size drill bit). Is this the basic idea?

I would guess that you would measure the thumb over the thumb hole and get an idea of what the degrees from horizontal are by where the sides of their thumb hit the hole.

I guess I don't know how far you move up and left total, or how to measure for that.

Any help out there? Thanks in advance.
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dR3w

"This space for rent"

leftyinsnellville · « **Reply #1 on:** September 24, 2009, 11:33:42 AM »

Rather than trying to move the ball in the jig, I just layout my ball as usual but I draw the (normally short) horizontal line that marks my thumbhole all the way across the ball.

Next I mark 55 degrees from that horizontal line on both sides (which lines up with the back and front of MY thumb, yours may be different) and then I draw another line connecting those marks. (That line should go directly through the center of where your vertical grip line and horizontal thumbhole line intersect.)

When I put the ball in the jig, I use the new line (connecting the 55 degree marks) to line up my ball. This results in the ball being turned clockwise in the jig from normal drilling position, but I'm a lefty. For right-handers you'd end up turning the ball counter-clockwise.

I then set my pitches as I normally do, and drill the hole. Then I shift the ball slightly to the left and right using the crank on the jig (usually no more than 1/8 in each direction) and drill the "sides" of the thumbhole out. If your going to use this method, you'll need to start with a much smaller bit than you would normally use or the thumbhole will come out way too big. I had to drop down at least 5 bit sizes to get a good fit.
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I wanna be a house hack when I grow up.

http://averagebowlersballreviews.com/

Edited on 9/24/2009 11:34 AM

kmanestor22 · « **Reply #2 on:** September 24, 2009, 11:57:06 AM »

You got the right idea, but 1/32" (.030") is the most you want to move at a time.
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Where is the bait? I'm goin' to jail!!! - Chocolate GAYzer

LaneHammer20 · « **Reply #3 on:** September 24, 2009, 12:44:27 PM »

lefty, do you drill your own stuff, and if you do what kind of drill do you have? I always thought you either worked in a pro shop or something with all the quipment you got.
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What is sandbagging???

FrontTwelv · « **Reply #4 on:** September 24, 2009, 04:05:17 PM »

I have a MUCH better method.
this will be all based off a 45* thumb angle.

You need a pitch guage with my method though.

take a ball that feels good. find out what angle your thumb is. instead of checking pitches based on the centerline and 'span' line, measure the pitches based on the 'angle' line. (flip the ball 45* counterclockwise) when measuring pitch. you will put the ball in the jig with the 45* angle and not the 90* span mark.

lay out the ball. draw in the horizontal line you would normally draw to hit the span correctly. then draw in the (45* line). make sure this line cross-sects the 'span' line and centerline.

draw a line horizontal from the centerline to the left of it about 1/32". this will be the first line you hit. (dont want to run out of slug). Since you have the ball in the jig with the 45* angle line all you ahve to do is move the ball sideways and not sideways AND up/down. move the jig small amounts. when it feels good jot down!!

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Drew Jordan
Columbus, OH

Edited on 9/24/2009 4:06 PM

bluerrpilot · « **Reply #5 on:** September 24, 2009, 10:29:49 PM »

quote:
Several years ago I purchased a pro shop setup with what I guess is the older version of the dual chamber vacuum jig from innovative. I got some lessons in the basics and have been drilling for myself and close friends mostly. I never really learned how to drill ovals into a thumb slug and was wondering if there was any information/video out there that would be helpful. I have an idea about how to do it, but if anyone could pass on a link or maybe provide a short tutorial I would really appreciate it.

I am guessing that after you drill the hole for the thumb you have to move the pitches both vertically and laterally a certain amount. So I'm guessing that if someones thumb fits in the hole with maybe 45 degrees from the horizontal, you would move the press up 1/32" and left 1/32" and drill. Also doing this at 1/32" down and 1/32" to the right (with the same size drill bit). Is this the basic idea?

I would guess that you would measure the thumb over the thumb hole and get an idea of what the degrees from horizontal are by where the sides of their thumb hit the hole.

I guess I don't know how far you move up and left total, or how to measure for that.

Any help out there? Thanks in advance.
--------------------
dR3w

"This space for rent"

You are correct. Once you have determined the amout of oval needed and the angle, you then move the tables in one direction. There is no need to go back and do the other side of the hole.

My thumb is 15/16th bit I then move the table .030" left and .030" forward make a second cut. then move again .030 L and .030 F This completes my oval for 45degrees
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"USBC is concerned that technology has overtaken player skill in determining success in the sport of bowling"

http://www.phxbowling.com/acba
http://www.viseinserts.com/

leftyinsnellville · « **Reply #6 on:** September 25, 2009, 04:47:00 AM »

quote:
lefty, do you drill your own stuff, and if you do what kind of drill do you have? I always thought you either worked in a pro shop or something with all the quipment you got.
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What is sandbagging???

Yeah, I drill my own stuff. I have an old Delta drill press. I don't work in pro shop...I'm a novice at best. I own so many balls because I have more money than brains.
--------------------
I wanna be a house hack when I grow up.

http://averagebowlersballreviews.com/

dR3w · « **Reply #7 on:** September 25, 2009, 03:06:44 PM »

Thanks everyone, I think I know what to do. I will experiment a little.

As for a formula (absolutebowling). it is just the Tangent of the angle.

In your case 39 degrees. Tan(39) = 0.8098 or 0.032/0.04 = 0.8

Thanks again,

Drew
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dR3w

"This space for rent"

Bigmike · « **Reply #8 on:** September 29, 2009, 08:29:37 AM »

quote:
Wow... just wow....

The most you should move a table when drilling for an oval thumb is 0.040in. To make wider, you must do it in multiple cuts.

The angle of the hole is NOT based on a "67 degree gripping angle", but the angle of the sides of the thumb in relation to the grip. For those "DIY" drillers without the proper fitting tools, a jayhawk angle quaterscale can give you a good estimate. Place the thumb in the ball and the fingers over the top of the fingerholes. Take the thumb out marking where the sides of the thumb is. Draw a straight line through those marks, and place the centre of the QS in the centre of the thumb, with the overbar in line with the centreline. Of course nothing is better than having all the tools needed, but this will get you relatively close.

Get a program that decides the ratio of table movement based on width of hole and angle of hole. 45degrees is = movement vertically and horizontally, but it gets harder to work out from there. Mine being 39degrees is a 0.040 movement vertical, and 0.032 horizontally. Moving the table in 1 direction rather than cutting each side of the pilot hole also is much more consistent in taper of the hole for those of you with weaker drill/mill heads.

For those of you with older jigs without mill heads, and without digital pitch indicators, etc, go out and buy an exactacator setup. You might think you get it pretty close, but you don't. Go to a good ball driller to set you up with a proper fitting thumbhole, then take a mould.

Exactacator will have them all identical, save you hours worth of working out the holes, and if you can install them properly, the exact angle is acheived.
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Get on the G train.... GLOBAL BABY!

www.900global.com

Absolute you nailed it. Turbo Pro Sect's also can give you the degree of oval correctly and if you use Ebonite Pro Shop Coordinator, you can get the cuts by following a couple of steps. And the Ebonite program does not make moves more than .040 inches.
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"Why don't you call me sometime.....when you have no class" ~~Rodney Dangerfield to Sally Kellerman, his college professor in Back to School ~~1986

Mike Craig - Storm Products Pro Shop staff -Columbus, OH

Slick300 · « **Reply #9 on:** September 29, 2009, 08:40:03 AM »

Call innovative John showed me how to do it his method is simple and precise.
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Ray Lathrop
Better Bowling Concepts

Author Topic: Drilling Oval (Read 7044 times)

dR3w

Drilling Oval

leftyinsnellville

Re: Drilling Oval

kmanestor22

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LaneHammer20

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FrontTwelv

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bluerrpilot

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leftyinsnellville

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dR3w

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Bigmike

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Slick300

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