View Full Version : Lathe questions

03-30-2011, 08:53 AM
1. Does the lever on the apron that changes the spindle direction change the motor rotation? This is on a 3 phase motor.
2. Is there a standard regarding which way this works. I was under the impression that lever up was forward. This was based on the thought that downward movement was easier in an emergency.
3. Is the spindle oil pump direction related? Seems like it would not be because operations can be performed in either direction.

03-30-2011, 09:03 AM
1. Yes
2. Most are up for spindle on CCW (normal rotation) as you're looking at the spindle from the operator position. The "official" rotation view of any machine is from the back of the spindle out toward the working end, clockwise is normal. I have seen a few machines setup to run it backwards (to me) by pulling up on the lever, but I see this as wrong. I guess it's really not that big of a deal.
3. Good question. I would think that the pump only works in the "normal" direction, but that the machine spends so little time in reverse that it's not a big factor in spindle life span. Better machines have a separate oil pump for the spindle that runs on it's own.

03-30-2011, 09:05 AM
On what I'll call a properly clutched lathe, the controls on the apron engage/disengage clutches in the headstock. The motor is running all the time in the same direction which avoids the inrush of current on starting. On mine up is forward, likely convention, and there's a lock out (you engage or not) to prevent going from forward to reverse although with fluid clutches I'm not sure it matters...might be more for operator safety, ie all of a sudden things are going backwards and when what you wanted was a emergency stop! The oil pump is likely (never thought about it before) off this part of the headstock that never changes direction else it would pump backwards

I say proper clutch lathe as the lathes I've seen have clutches in headstock controlled by the apron but it was pointed out to me recently that several lathes have apron levers for forward/reverse that don't actually control clutches but are just an motor switches...What lathe, and is there a manual?

03-30-2011, 10:21 AM
All the lathes that I've worked on from small to very large you push the handle down to go forward. On my Monarch lathe the oil pump rotated with the spindle thats why it did not come with reverse but with just a little plumbing the gear pump was able to pump oil to the fittings whether the spindle was going forward or reverse, you just need some check valve, unions, tees, a little bit of pipe, a gear pump usually only pumps in one direction but by putting in check valves the suction and discharge stay the same, the only thing with the Monarch was that you had to reverse the motor, but with 3 phase not a problem.

J. R. Williams
03-30-2011, 10:50 AM
My Clausing-Colchester lathe has two clutches in the headstock gear box that reverse the spindle with the motor running in only one direction.

03-30-2011, 12:30 PM
On my TUM-35, the oil pump is driven from (actually "part of") the main gear box in the bottom of the lathe - that changes direction based on the motor contactor, and delivers pressure either way.

The apron lever is "up for forward", centered for off, and down for reverse. If you knock it down from forward, it will catch in the center detent - off.

03-30-2011, 12:57 PM
The apron lever is "up for forward", centered for off, and down for reverse. If you knock it down from forward, it will catch in the center detent - off.

That's the way every machine I've run has been, and the instructions in the manual for my dad's Victor 1640 reads that way too.

I find it strange that duckman, only about 20 miles from me, has had exactly the opposite experience.:confused:

03-30-2011, 01:54 PM
Jet GHB-1340A, lever down for forward, up for reverse.

(Forward= CCW rotation of chuck as viewed from the tailstock)

03-30-2011, 01:57 PM
When I got my 12 x 40 Nova lathe from MSC in '95 it was up for forward and down for reverse, the normal standard. However, when the lever was up it was under the driveshafts and right up against the lathe bed - hard to get at. So I reversed it to go down for forward - very easy to get. This is a Chinese lathe that looks exactly like all the 12 x 36 ones in Enco, etc. I have made a few upgrades and taken good care of it. It is still accurate and working good in spite of being used almost daily for over 15 years. I have replaced the original motor and 3 on/off switches.

03-30-2011, 02:15 PM
When I retired and moved the lathe to the home shop, I inadvertently reversed the rotation. This is a Nardini 1230 with three-phase motor. I had always used up lever for forward direction. I had been using it that way long enough that the movement had become a conditioned reaction. I just changed two wires and had things working the way they always had. It was mentioned on another forum that some oil pumps did not work in reverse. Fortunately my oil pump is located so that it delivers the same amount of oil in either handle location. I think this means that the pump is located so it turns in the same direction all the time.
My lathe has a magnetic brake and the motor stops and starts each time the control is moved to or from the center position.

The Artful Bodger
03-30-2011, 02:23 PM
Down for forward just like a light switch which is down for 'on'. Also carriage traverse wheel on the right hand side of the apron.:D

BTW, with single phase motors, if you do not let the motor come to a halt switching from forward to reverse may do nothing at all!

03-30-2011, 06:51 PM
Down for forward just like a light switch which is down for 'on'. Also carriage traverse wheel on the right hand side of the apron.:D

I guess that would be right for "down there", Up here on top o the world we flip the light switches up for on:D


03-30-2011, 07:42 PM
The series 60 Monarch I worked on ran the headstock oil pump off a cam, it was a piston pump. So no matter which direction the spindle ran the pump always pumped.

The Artful Bodger
03-30-2011, 08:01 PM
I guess that would be right for "down there", Up here on top o the world we flip the light switches up for on:D


You might do that in your country but it is by no means universal in northern hemisphere countries.

03-30-2011, 08:33 PM
Pretty much just the USA and Canada. I had problems with that for years;)

Then I move into a house with the latest (70's) switches. One button for on and another for off. Problem was... on a three-way cricuit, you never could tell which switch to press to turn the lights on or off... frigg.... tossed all of those within a month.

03-30-2011, 09:08 PM
Well, that sure cleared things up :D

03-30-2011, 10:52 PM
that lever operates a rod that activates 2 micro-switches that directly control motor rotation and indirectly carriage direction on my Cadillac . my oilers are the sling and splash kind.

03-31-2011, 10:33 AM
Up is forward and down is reverse on everything Ive ever run.

Call me ignorant or maybe Ive just never noticed, but Ive never seen a reversed light switch, and Im up to 14 countries outside US/Canada/Mexico/Islands. Up is on, down is off. On sideways switches, left is off, right is on.

03-31-2011, 01:06 PM
You have never been here then:)

03-31-2011, 01:47 PM
Been on overnight trips to England and Ireland half a dozen times, and on two seperate tours roaming London and the English countryside for a week at a time. Maybe they Americanized the hotels and military posts?

03-31-2011, 05:57 PM
Artful: There are still a few houses where the light switches are still up for on. This dates from the second world war. In the blackout, a nearby bomb might rattle the switch down and it wouldn't do to have lights going on to make identification of streets from the air easier.

This thread has been useful to me as I'm still trying obtain or make the components to construct the apron lever on my Colchester Bantam and the associated mechanism, although I'm afraid it's one of those low grade lathes where the lever changes the direction of the motor.