Another question for drillers

[bluerrpilot]

Just wanted to hear other opinions on the subject. How do you drill ovals? With the drill press or manually by hand. With maybe a drill and sanding drum or ……whatever else you may use. If you use the drill press, do you have a formula or a specific way that you do it? Maybe something that isn’t so time consuming. I have always done mine by hand for 2 reasons. One, I don’t have a ton of material to remove for the oval. And two, when there are 5 customers in the shop waiting for balls to be drilled, using the press is very time consuming. I understand people will say they use the press because thats the only way to repeat the results. But for me its about feel. And I can do it manually and get all my thumbs to feel the same.

[BubbaRay]

There is a lot of opinions about drilling oval holes and the use of doing it with drill bits. You can use a drill bit but there is some problems with this. Drill bits do not have the right cutting tool geometry for cutting on the side of a hole. When you make a side cut for an oval hole a drill bit will pound because there is only one tooth cutting and the drill will want to walk away from the hole. If your drills are very sharp it will work for a while, but once the corner polishes a little from the abrasive cores, it will want to push away from the edge of the hole.

What I usually have see done is the thumb hole being worked by hand on the sides of the thumb hole where it needs to be ovaled out. This can be done slowly with a rasp .

If you have oval thumb holes in all of your equipment What I would suggest is going to your po shop and take the ball that fits your thumb the best. Have him make a custom oval thumb slug. this way when you get another ball drilled all he has to do is punch the thumb out for the oval slug and BAM! you are done.

[bluerrpilot]

Thats another reason I dont use the drill for ovals. The bits will chatter to a certain extent. Unless I use an end mill bit. the biggest reason is time. Its much faster for me to use a drill with a sanding drum to create that oval. But its difficult to explain to customers when they say "how do you expect to repeat your results that way" Not too many people have asked about exacticating a thumb so we dont even have that kit.

[BubbaRay]

The end mill bits are great for doing the ovals when they are sharp and new. but after a while when they satrt to dull. the same problem arises. they do last longer though. As for the custom thumb slugs, it is worth having a kit and try and start to promote using them to customers.

[Stampy79]

I use the drill press. Our bits cut on the side. I know my oval size and so on, so I cut the hole, then turn the ball 44 degrees to match my thumb. Then I put the pitches into the ball(They change when I rotate the ball) Then I use a 49/64 bit to take aprox 1/16 off each side. Then I take it out and smooth it with a bevel knife and sand it down. Then we use a piece of scotchbrite pad on a sander and smooth it off. Makes for silky smooth thumbholes. If you like them that way ! Of course then I add my Magic carpet and a piece of tape as needed. And there you have the Stampy Thumb as some of you have this week in the balls you bought.

[pba6285]

We use Vise Pro V2 ovals at my shop.

I have an oval movement chart that you can compute the moves for Mills with Digital Readouts.

Plus my shop software (we use Gripware) will compute the table moves for you