Fixture for holding bowling balls while drilling fingerholes?

Fellas,

Gotta buddy at work who's a good bowler. Has several rings with 297 or such on them. I bowl about once every five years and am glad to see it go straight for the first 5 frames, then I'm just trying to make sure it stays in my lane.

He's buying bowling balls off eBay and drilling them himself in a drill press. Probably selling 'em too - he's at the rink all the time.

He's asked me to help him make something to hold the ball while drilling the fingerholes. I don't think he has a lot of experience with drills. He could hurt himself, so he needs fixture for more than just making some $$$.

Anybody know of some quick-n-ready plans for a jig?

I'm thinking of cutting a ring of 6 inch Sonotube and gluing it to a board. I want the ball to sink down into the Sonotube collar but not all the way to bottoming out. I'll put a piece of closed-cell foam in the hole to let the ball nestle into it at the bottom. This should help keep the ball from spinning, maybe a li'l vibration dampening too.

Cut a hole in the board, pass a bolt through it, and then this whole setup will be held from spinning off the drill and into the floor.

Still, the ball needs to be held down more tightly in the Sonotube ring. So far, all I've got is a way to prop up the ball and keep the jig itself bolted down. How to snug down the ball?

Lastly - is drilling bowling balls a tricky deal or straightforward? I'd hate to see this guy waste $600 or more ruining good bowling balls and selling junk to people.

I hate to say it and will have to blank it out if I pass on y'all's responses, but this guy is about 80 IQ. He's full of energy and gungho but that's about all. If there is some tricky angle to getting a good fingerhole drilled, he'll probably never figure it out himself. I'd appreciate a pointer or two, especially to some ball-drilling websites or such.

I modified one for a guy once. The ball is was not rotated during the drilling process. The drill was on an articulated type arm. It sat on a ring similar to your description and was held down with another ring on top. Line contact on both rings held it pretty good.

Look at wood working vacuum chucks for a quick setup idea(use a shop vac for the vacuum.)

have him invest in a used ball drill. angles and locations as well as size are very important. also the break around the hole is important and different bowlers like them different ways, and there is probably to much to be left to chance in trying to figure out how to do it on a drill press and those machines are not that much new, on the other hand if he is already drilling them and selling them and he and the people he is selling them to are satisfied then your fixture sounds like it would just make it easier.

http://ultimatebowling.com/equipment.asp

Check out that one at the bottom of the page.

Nervis1

Very amusing - in this world there had to be a bowling/machinist geek!

Cheers,
Bob Welland

I would use some of that "anti-slip" open cell foam used in roll-around toolboxes and also sold to keep area rugs in place on hardwood floors, inside the fixture to improve the "grip".

Back that up with some Destaco toggle-clamps and I think you have a basic ball-holding device setup.

As far as having a repeatable way to drill the holes, in a cheap/easy manner, I'd drill the first hole (doesn't matter where, right?) and then insert a turned pin that's a close fit.

Fixture the turned pin against some kind of stop, and drill the next hole.

Same deal after that, now there are two pins to locate the final hole.

Easy for me to type , but needs some more thought to actually make it a reality. However, a system of pins, stops, and drills shouldn't be super expensive to build.

You might want to tell your buddy to get the expensive one's drilled by a pro. Bowling ball drilling is "scientific" with a little art mixed in.

The balls' ability to hook and the number of revolutions it will do consistantly is all dependant on where the location of the "pin" (that yellow/orange dot on the ball near the badge...that indicates CG of the internal offset weight) is relative to the finger holes.

Oops, so the first hole location does matter

Oh well, shows you know what I know about bowling...I had no idea there was an internal offset weight...I just try for max velocity, keep it between the lines, and hope "pin splatter" makes up for my inability

I was a state champion 30 years ago but ball drilling techniques may have changed since then as I haven't picked up a ball in a long time. Back then, the proper tools came in a set. If your buddy doesn't already have one, he'll need a "try" ball master. It's regulation ball size and has locations for a wide variety of finger sized bushings. You select the proper ones to fit the owner's hand with a conventional or fingertip grip and then the ball can be rotated on a central axis to get the spacing right. At that point, the measurements are transferred to a template or ball drilling jig and the drill indexes I remember seeing were all Morse taper twist drills in 1/64 increments. The guy that used to do my fitting had a big Rockford gear head in the pro shop.

In regulation play, you are allowed so many ounces of side and top weight - the former helps it break and the latter carries through the pins. If you exceed the standards, the ball will not be allowed for tournament. Drilling balls properly definitely requires some training and know-how.

drill the first hole (doesn't matter where, right?

Click to expand...

That's what I thought, until another machinist showed me these photos from the Dyno-Thane website:





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Barry Milton

And those are only the tip of the iceburg.
The pin is important but so is the CG and the mass bias. Finger and thumb pitch and cast make it easy to get out of the ball and to get the right release.
If you're going to build a jig, it needs a repeatable and accurate method of setting pitch. A 1/16th in change in pitch makes a big difference. You may be better off suggesting that he go to a bowlers supply house/wholesaler and buy a jig. It's a lot easier.

Bill

In my opinion, after35 years bowling, it's easier to just find someone that is already good a drilling balls and have him do it. Bowling balls are pretty pricey. Even online stores are getiing $150 and up for high end ones. That's too much money for me to screw up.

Rocky

My motto is, "Anything can be found on eBay. If not today, then keep looking."

Pro bowling ball drilling outfit ($1999.99 now, with a day to go)

Book on drilling bowling balls $17.50 BIN

Larry

Forget the 'Pro bowling ball drilling outfit', I want the Pontiac in the background!!

Larry,

For $2000, I'd want something better than a Jet drill press & a half-fast jig

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Barry Milton

Hey, if the guy is knocking on 300 he sure as hell should already know about how balls are done right. Woudln't you think?

Dumb Question, about drilling a bowling ball... When you drill the holes, do you keep the drill at X 0, Y 0, & rotate the ball? In other words, while drilling, is the drill always pointed at the center of the ball ???

jkilroy,

I've worked with this guy for a few years now. He's hard to characterize. More natural energy and with a genuinely upbeat attitude than 95% of the folks one will ever meet. There's a lot right there to respect.

But he's missing something on the upper end. I don't say this lightly. In fact, if he sees this message I'm gonna be in big trouble, as his brother is the manager.

I worry about two things - his hurting himself in a drilling accident, and ruining good bowling balls he's buying new off eBay and drilling for other people.

I hear he's a helluva bowler. Not championship quality, but he loves it and I bet he's got an excellent 'feel' for what a bowling ball needs to do. No way, though, that he'd be able to take a discussion about CG dots, rotational imbalances due to interior weighting, etc. and come up with a mathematically sound decision on where to drill the holes. Hell, that kind of thing is beyond most of us here. You're talking about dynamic forces? Forget it...

He'll end up dropping holes in some spot that seems right to him, or maybe just dropping them at random, not even knowing about CG, weighting, and the rest.

My main goal is to help him come up with a jig so he doesn't mangle his fingers. I'll let him worry about the rest of it.

Use two rings, one for the base and another up toward the top. Think of it as a round version of a battery hold down bracket in a car.