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View Full Version : Looking for Jet-16 Mill/Drill Owners - many questions



wrwetzel
09-19-2012, 09:04 AM
I just acquired a 1986 Jet-16 Mill/Drill (table 9 3/8" x 23 1/2"). I'm hoping to find an owner or two who can answer many questions I have about it. As a point of reference I also have a Pratt & Whitney Bench Mill and a Van Norman Model 1/2 but very little experience with any of them.

1) On my other mills I always lock the axes that I'm not actively moving. There are no locks on the Jet-16 table but there are two adjustment screws on each table axis for gib wear which I could replace with locking handles. Have you ever had a need to lock the table? Is your backlash so little that the table doesn't jump when changing the direction of cut?

2) What is the backlash on each of your three axes?

3) My Pratt & Whitney has a tab for locking the spindle when tightening / loosening collets. I can find none on the Jet-16. How do you prevent the spindle from turning when tightening the collet?

4) One recommendation for tightening collets suggested 1/4 turn after the drawbar snugs up. In your experience is this adequate for holding end mills such that they don't climb out of the collet or should I always use end mill holders instead of collets?

5) The head of the Jet-16 is locked to the column by three bolts. Two of the bolts have conventional nuts - the other is tightened with a wheel with three holes for a handle much like the quill handles. When do you tighten all three? When do you leave the nuts loose and tighten only the hand wheel?

6) The pulley on the main spindle is about 1/4" too low and is not aligned with the idler pulleys and motor pulley. I resolved this with a shim on the taper where the spindle and pulley meet. Have you had this problem? Do you have another solution?

7) I can find no reference mark for the micrometer dial on the cross-feed. There is one on the right side of the long feed. And yes, I have scraped the paint down to bare metal in the region where I would expect it to be. Is this the case with your Jet-16?

8) The mill included two handles, 6" long x 3/8" dia, with red balls on the end. These look like small versions of the quill handles. I can find no place for them and wonder if they are interlopers from another tool. Do you have such handles? What are they for?

9) Please describe the handle(s) (length, diameter, ball) that you use to tighten the head to column.

Thanks much,
Bill Wetzel

Rex
09-19-2012, 05:28 PM
I am surprised no one has chimed in here in 3 hours.
You can find an Enco RF30 manual online that will probably match your machine.
I can email you a copy if you send me a private email.

I would also recommend the Yahoo group for round-column mill-drills as a great resource

wrwetzel
09-20-2012, 12:05 PM
Rex,

Thanks much for your note. I was able to find the Enco RF30 manual online. It is indeed quite similar. I'll have a look at the Yahoo group you mentioned.

Bill

Rex
09-20-2012, 12:33 PM
Good for you. I have a little more time so I'll take a shot at some of your list items:

1) On my other mills I always lock the axes that I'm not actively moving. There are no locks on the Jet-16 table but there are two adjustment screws on each table axis for gib wear which I could replace with locking handles. THAT'S WHAT YOU DO

Have you ever had a need to lock the table? ABSOLUTELY, ON ANY MILL

Is your backlash so little that the table doesn't jump when changing the direction of cut? EVEN ON A NEW MILL THE FORCE OF THE CUTTER CAN MOVE THE TABLE>


2) What is the backlash on each of your three axes? DON'T RECALL BUT .020 IS COMMON

3) My Pratt & Whitney has a tab for locking the spindle when tightening / loosening collets. I can find none on the Jet-16. How do you prevent the spindle from turning when tightening the collet? I RECALL A CHROME HANDLE ON THE LEFT SIDE OF THE SPINDLE

4) One recommendation for tightening collets suggested 1/4 turn after the drawbar snugs up. In your experience is this adequate for holding end mills such that they don't climb out of the collet or should I always use end mill holders instead of collets? I USE COLLETS 75% OF THE TIME. "SNUG" is GOOD ENOUGH. I ONLY RECENTLY BOUGHT ENDMILL HOLDERS

5) The head of the Jet-16 is locked to the column by three bolts. Two of the bolts have conventional nuts - the other is tightened with a wheel with three holes for a handle much like the quill handles. When do you tighten all three? When do you leave the nuts loose and tighten only the hand wheel? I'D TIGHTEN ALL 3. MINE HAD NO HANDWHEEL. IT DID HAVE A CRANK TO RAISE and LOWER

6) The pulley on the main spindle is about 1/4" too low and is not aligned with the idler pulleys and motor pulley. I resolved this with a shim on the taper where the spindle and pulley meet. Have you had this problem? Do you have another solution? I WOULD TRY TO MOVE THE MOTOR PULLEY (OR PERHAPS THE MOTOR) INSTEAD.

7) I can find no reference mark for the micrometer dial on the cross-feed. There is one on the right side of the long feed. And yes, I have scraped the paint down to bare metal in the region where I would expect it to be. Is this the case with your Jet-16? JUST CUT YOUR OWN. LOCATION IS NOT CRITICAL.

8) The mill included two handles, 6" long x 3/8" dia, with red balls on the end. These look like small versions of the quill handles. I can find no place for them and wonder if they are interlopers from another tool. Do you have such handles? What are they for?

9) Please describe the handle(s) (length, diameter, ball) that you use to tighten the head to column.

wrwetzel
09-20-2012, 12:44 PM
Thanks much. I appreciate your thoughts.
Bill

bruto
09-21-2012, 12:20 AM
I scanned my old Enco instructions (more or less like an RF-30) here: https://www.box.com/shared/e21b39lgcs


My enco does have locks for the unused axes. I don't think they're much more than a couple of toggle-headed setscrews that push the gib in. If yours lacks them you could probably just drill and tap the holes and make your own.

There's a little allen head screw for locking the spindle. It may not be obvious.

KIMFAB
09-21-2012, 01:17 AM
I had one of those several years ago and got a good deal on a full size Lagun that I had room for so the Jet went down the road.
I found that the head still would turn on a heavy cut even with all 3 bolts very tight.

I tried fastening the head moving rack on the back and it did help to a certain extent but those round column units do require a gentler touch.
If you do try the rack fastening trick you have to use smaller screws, I think I used a #10

Good luck with your new toy.

pbarratt
10-04-2012, 05:18 PM
Bill,

I inherited one of these from my father some years ago. I agree that backlash in the stock setup will cause table movement if you don't take it into account. As far as locking the head goes, I have never used more than the one lock (the short handle with the smooth end and a ball on the other) and never had the head move but then, I don't tend to be very aggressive. Yet. The other short handle is for the quill lock.

I ended up converting mine to CNC with ball screws and have been very happy with the results. I use milling cutter holders but I got them with the mill. The original mill has no locks on the axis but after fitting with ball screws, I've not needed them.

My cross feed dial has a reference mark where you would expect it to be. They must have missed it on yours when they made it.

The motor pulley was too low so I added a spacer collar to the shaft. Also, the motor shaft is keyed but the pulley is not, just has a set screw. Crude. I may fix this during a slow day.

I use my left hand to 'clamp' the spindle when tightening or loosening the draw bar. Sounds weak but has been totally effective.

Let me know if you have any other questions.

Peter