jet mill/drill questions

I am considering purchasing a Jet JMD-18PFN for drilling holes in
bowling balls. I'm upgrading from an old Walker Turner 15" drill
press. If anyone has this machine, I would appreciate some advice.
I would be using the power downfeed most of the time, but I also
need manual occasionally. Does it only have two handles for manual
downfeed, and if so could another handle be added without too much
trouble? Also, I need to move the table quickly in the x and y
directions when setting up to drill a ball. Is there a way to do
this or do you have to slowly crank the handles. Thanks in advance
if anyone has any info.
Reply to
tom
Loading thread data ...
Thanks, Joe, for your reply. I looked at a Harbor Freight machine of the same basic design and was not impressed. It's made in China and it's pretty rough. I assume the Jet is made in Taiwan. I've had a little experience with their woodworking machines and they're pretty decent for the money.
Reply to
tom
I have done a little bit of milling on an early-90s Jet mill-drill. I was pretty unimpressed myself. Still, it got the job done. I don't think there's much difference between the import mill-drills compared to the difference between any of them and a Bridgeport or clone. Just my 2¢ worth, I know a ton of guys have 'em, use 'em, like 'em. No spindle lock? Lose registration every time you move the head? Chiwanese threads on the x/y feeds? Sheez. - GWE
Reply to
Grant Erwin
I have a JMD-18 without power down feed. Bought it new in 1997 or so. I am almost positive it is made in china. The motor said made in Taiwan and I went through three of them before giving up and buying a leeson motor. In my opinion, they are way overpriced for what you get. The machine cost me about 1500 and another 200 for the stand (plus tax). For the same money you are much better off buying a import knee mill and getting a lot more for your money.
Why do you need power down feed for drilling bowling balls?
Reply to
Charles A. Sherwood
No liners on cheap bowling balls. After drilling, the holes are sanded smooth, and the edges beveled. The tool for that is basically a die grinder with a long mandrel. A piece of sandpaper, shaped kind of like a figure-8, held to the end of the mandrel with a screw.
When I was in college (when dinosaurs roamed the earth ;-), I worked in the sporting goods department at K-Mart (discount stores chain). I drilled the bowling balls. I learned all I know in a 1 hour session with the factory rep. I used a normal drill press with a special jig to hold the ball. The jig had X and Y feeds (manual) like a mill table, but the feed was pretty coarse. I marked out the the ball with a grease pencil and a strange looking, curved triangle thingy with a couple of arms added to it. Lined up the center of the ball (marked at the factory by a dot in a circle) with the drill spindle by eye using a pointed rod. Locked the ball down, then cranked over to hole marks, changed to the proper drill, and drilled the hole. Repeat for the other two holes, then sand with the tool mentioned above. The customer's name or initials where stamped in with standard steel stamps.
The pro shops have nicer equipment, and don't necessarily drill exactly the same way I outlined above. The ones I've seen do use a drill press, not a mill. They know how to drill balls for special gripping styles, and they know a whole lot more about properly fitting a ball.
I don't think a mill is necessary for drilling bowling balls, but it wouldn't hurt. The only downside is that mill table feeds tend to be fine, which means a lot of cranking. It would be cool to CNC the mill, and do the whole job automagically. One could do some neat engraving on the ball with a small cutter.
-Ron
Reply to
Ron DeBlock
I'm surprised they don't have dedicated CNC ball-drillers already. =20 Have a "measuring ball" that has changeable, movable holes. Adjust it for the best fit on the buyer's hand, then put the ball in the drilling rig and press the "go" button. An automatic tool changer option might speed things up as well. =20
To reply, please remove one letter from each side of "@" Spammers are VERMIN. Please kill them all.
Reply to
Doug Warner
Joe, the holes do not usually point toward the center of the ball and all three holes are not parallel to each other. You're right about equipment costs. Nobody does enough balls to justify a cnc setup or anything like that.
Reply to
tom
There is a science to bowling ball drilling. Click on some of the links on this page to get some ideas.
formatting link
And from:
formatting link
"The pitches are the angles at which the holes are drilled. Drilling the hole toward the direct centre of the ball is zero pitch. Drilling the holes at an angle toward the centre of the grip is forward pitch. Reverse pitch is drilling the hole at an angle away from the centre of grip. Finger pitches are largely determines by flexibility. The holes need to be drilled at angles that fit the amount of flexibility in the fingertips. Over time, bowlers tend to lose flexibility in the finger joints and need more reverse pitch in the finger holes."
"I cannot express enough the need to seek an IBPSIA certified pro shop operator when drilling your equipment. Kmart and Wal Mart are NOT the place to have equipment drilled"
Hope this helps.
Lane
Reply to
Lane
I don't really need the power downfeed, but it would be nice to not have to pull on that handle all day long. The Jet model with the downfeed has a longer column (more clearance under the spindle) which I may need, depending on what jig I end up using to hold the ball. Yes, most better bowlers use inserts in all three holes. The holes are drilled larger to allow this. A lot of pro shops are going to the small milling machines over drill presses over the last few years. The new balls have cores made up of several pieces of different densities, and if you use a drill press sometimes the bit will wander off center if you hit the edge of one of those pieces inside the ball. The milling machine has a heavier quill and spindle, reducing that problem.
Reply to
tom
will not work on
Glad to be of help. Lane
Reply to
Lane
Usually, each hole points in a slightly different direction A hole that points toward the center of the ball has "zero pitch". Pitch is achieved by moving the table in the x and y direction. And each customer has different pitches, so one three spindle head would not fit everybody.
Reply to
tom
It was not the case when I drilled the balls. The pro shops do it differently, adjusting the angles to the customer's grip requirements.
The way I was taught, the holes were all parallel with the spindle axis. The ball was not rotated, only translated in X and Y.
Please remember that I was working part time for minimum wage, at a discount store, with minimal training. The balls were cheap, drilling was free, and the results were usable. For anyone serious about bowling, I recommend a pro shop.
I wonder if my brother uses some of your equipment. He's at Picatinny, part of his job is disposal of old munitions.
-Ron
Reply to
Ron DeBlock
I'm the guy who used to drill the balls at K-Mart. I agree with Lane. The pro shops do a much better job. It's not the drilling that's difficult, that's a simple machining job, I'm sure anyone on this newsgroup could do it. Measuring and fitting the customer properly requires a lot of specialized knowledge, that's where the pro shop has a huge advantage.
-Ron
Reply to
Ron DeBlock

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.