"Put it in 'R' for Race"

[Bill_Cook]

I’ve recently gotten a 16 x 30 American Tool Works High duty lathe (gear head). Electrically and mechanically it has no provision to run in reverse. Is it possible that it isn’t ment to be run backwards? Maybe the lube pump in the head won’t pump in reverse? I’ll be driving it with a VFD, so reversing will be possible.

Also, would running it faster than the 580 RPM rated speed hurt it, assuming the chuck can handle it? It came with 8” and 17” 3 jaw scroll chucks, a 17” 4 jaw, and a 17” face plate, plus a smaller dog plate. (The actual swing is 18 ½”.)

The serial number indicates it was built in 1940, but 39 is stamped after the serial number.

[Bob D.]

Have several American lathes of that vintage where I work. They all reverse the motor electrically to change spindle rotation. Since your running a VFD I assume your motor is 3 phase. Find it hard to believe there are not two mechanically interlocked motor contacters in the electrical panel for forward and reverse. Have never seen a lathe that couldn't reverse the spindle.
You can probably overspeed it ok to some degree but wouldn't by much. The motor rpms will get much higher than the spindle and you don't want the motor coming apart. That, and old motors aren't VFD rated and you can run into problems with the winding insulation.
Bob

[liveaboard]

I have an old lathe. the motor looks like a museum piece.
I looked it up, and when the rpm doubles the force trying to explode the armature increases by 4x.
So I limited my VFD to double rated motor speed, so far it's still intact.
It does sound a bit exciting at 2x speed.

Regarding your coolant pump; if it's driven from the main motor, you'll just have to change that and add a separate one.

[spro]

-doubles, More flexible lathes with a long motor belt can go "figure 8" for awhile.

[Bill_Cook]

Thanks for the help. The only info I’ve found on it is some sales literature over at Vintage Machinery.

The machine had been protected and stored for 15 or 20 years. Before that it had been used in a millwright department.

The motor is more modern. It’s mounted on a separate, fabricated stand with it’s pulley directly under the pulley on the headstock. It’s quite possible it was originally line shaft driven.

The electricals involve a two button switch mounted on the lathe running to the pecker head through a piece of flexible conduit.

I don’t have a pressing need for speed, and other than my desire to see it make some big thick chips, it won’t be worked too, too hard.


Thanks again

B C

[Bill Shields]

Spindle speed limit may be more a function of the spindle bearings than anything else. Is this a sleeve bearing or roller / ball bearing spindle? over speeding a sleeve bearing can be a big problem

if it is sleeve bearing there is the possibility that it is not setup to properly lubricate the bearing surface(s) running in reverse. While I have never specifically looked for (or heard of) such a condition on a lathe, I have seen other industrial equipment that should not be run in reverse.

[johnfreese]

I had a 40s vintage Pratt & Whitney 14" lathe. There was no provision for reversing the spindle. It would have been possible to install a reversing switch on the motor. If the machine were run in reverse the lube oil pump would not provide oil to the gears and bearings.

[Harold_V]

Hmmm. I can't even imagine owning a lathe that had no reverse capability. It's a function I use routinely when operating my lathe. Once you've had it, it would be difficult to operate without it.

H

[Bill_Cook]

According to the brochure, the headstock is '100% anti-friction'. http://www.vintagemachinery.org/pubs/1004/3598.pdf

Gear oil is pumped up into a small reservoir in the top cover of the headstock that drains into some of the bearings. I can take the cover off of it to see if it fills in reverse. It would be a shame if it doesn't, but I suppose I can learn to get by without reverse.

Other than the pealing, gloppy re-paint, it's in surprisingly good condition, so I won't be totally disappointed.

When I get it up and running I'll post the results.

Thank You all for the information.

Bill Cook

[NP317]

When running in reverse, if the pump does not pump you could always manually put oil into the reservoir for the bearings.
RussN

[liveaboard]

It seems to me that the way it's built, with oil reservoirs instead of directly pumping the oil into the bearings, is so that it can be run in reverse for a minute or so without trouble.

Unless you need / want to run backwards for a longer time, you're good.

[johnfreese]

My current lathe is a Nardini. Both the headstock and the apron have cam-driven piston pumps. I get reliable oiling regardless of direction of rotation.