BallReviews
General Category => Drilling & Layouts => Topic started by: dR3w on September 22, 2013, 02:47:15 PM
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Hi,
Are there any instructional videos or articles on drilling oval thumbholes out there?
Any information is appreciated.
thanks,
Drew
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I am not a driller, but I found the following in some earlier topics on this site and it may be of help to you.
http://www.jayhawkbowling.com/Pro_s_Corner/Pro_Shop_Forms/ovalfittingsystem.pdf (http://www.jayhawkbowling.com/Pro_s_Corner/Pro_Shop_Forms/ovalfittingsystem.pdf)
http://www.innovativebowling.com/pro%20shop%20info/The_Math_Of_The_Oval_Angle.gif (http://www.innovativebowling.com/pro%20shop%20info/The_Math_Of_The_Oval_Angle.gif)
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Yeah, you just need to google it and find a chart somewhere. I'd try to explain it, but without a video or pictures it's confusing.
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For a right hander, would you always move down and right? As if to elongate the hole downward? Or do you move up and left as well? Basically with a round hole you are measuring span from the top of the hole. Is it the same with an oval?
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Yes, still measure cut to cut. For a basic oval you will make 2 or 3 cuts as you say, down and to the right. For some odd shaped thumbs or if you are using a different size end mill to make cuts you may also cut the other side of the hole, or even make notches to custom fit a thumb.
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Yeah, this is correct. If it's a larger thumb and the oval is wider than .090 too, you may have to go up and left for a cut or two, but be aware that does shorten the span slightly. If at all possible though, go down and right, it keeps all your measurements correct.
Yes, still measure cut to cut. For a basic oval you will make 2 or 3 cuts as you say, down and to the right. For some odd shaped thumbs or if you are using a different size end mill to make cuts you may also cut the other side of the hole, or even make notches to custom fit a thumb.