Which levers can I move safely when the chuck is spinning?

[twooldvolvos]

I have been becoming familiar with my 1973 South Bend 10K lathe. One thing I would like some advice on is when it is OK to move the levers when the chuck is spinning. It seems that this is not a simple question since there are several factors to consider. So I made a table and filled in the Middle column with my best attempt at Y or N. Any advice is appreciated. I would prefer not to turn the lathe off every time I move a lever for convenience but I am more interested not damaging my machine. Thanks.

Lever Description	OK to change when chuck is spinning? (Y/N)	Note
Feed change lever up position	N	On apron Longitudinal feed Assuming lead screw is turning
Feed change lever middle position	N	On apron Threading Assuming lead screw is turning
Feed change lever down position	N	On apron Cross feed Assuming lead screw is turning
Threading lever down position	Y	On apron Half nut disengaged Assuming lead screw is turning
Threading lever up position	Y	On apron Half nut engaged Assuming lead screw is turning
Lead screw lever up position	N	On head stock Reverse lead screw
Lead screw lever middle position	N	On head stock Neutral lead screw
Lead screw lever down position	N	On head stock Forward lead screw
Transmission levers	N	Bottom of head stock 5 positions left lever 8 positions right lever

 

[markba633csi]

It's been a while since I ran a South Bend but as far as I remember, as long as the star wheel clutch is not engaged, any of the levers can be moved when the spindle is turning. I stand to be corrected on this.
Also, if I recall correctly, the half nuts are engaged when the half nut lever is up, not down
-Mark

 

[Shootymacshootface]

I have a Clausing 6329, and the owners manual doesn't give much advice on this subject.
I let the machine tell me what it likes to do. Most levers that engage a drive or change speeds are only moved without the motor running, except for the controls on the apron. I do regularly disengage the lead screw while it is running with no load on it.

 

[MrWhoopee]

Keep it simple. You may engage/disengage the half-nut or carriage/cross-feed (starwheel or lever) when the chuck is spinning. That's all.
edit: You may also shift the feed selector on the apron (carriage, threading, cross-feed) and you may DISengage the leadscrew.

 

[twooldvolvos]

It's been a while since I ran a South Bend but as far as I remember, as long as the star wheel clutch is not engaged, any of the levers can be moved when the spindle is turning. I stand to be corrected on this.
Also, if I recall correctly, the half nuts are engaged when the half nut lever is up, not down
-Mark

Thanks, Mark. You are correct on the half nut.

 

[SLK001]

With the spindle turning, do not change the reversing lever or any of the gear box levers. It's an unsynchronized transmission without any clutch, so any changes here can hurt.

On the apron, the cross feed and carriage feed levers can be changed with the clutch out and the spindle turning. The half nuts are engaged with the spindle turning (but only on the marks of the thread dial).

 

[Winegrower]

I never really considered changing the longitudinal/cross feed selector while running, mainly because on every lathe I've had (3) what I almost always want to do is feed carriage right to left and cross slide out to in...but to do that, the direction of the feed rod has to be reversed also...so need to stop spindle anyway.

Why is it that lathes seem to be designed to select either (Right to left - In to out) or (Left to right - Out to in)? Seems not optimal. Anybody else think this? What am I missing?

 

[MrWhoopee]

Why is it that lathes seem to be designed to select either (Right to left - In to out) or (Left to right - Out to in)? Seems not optimal. Anybody else think this? What am I missing?

I thought it was just me. Probably a matter of requiring one more gear in the train.

 

[Winegrower]

Right, MrWhoopee! For that one gear, and your assurance I can change the cross/carriage feed while operating, I could be really efficient. Picture it: Turn to diameter, flip the cross feed selector, face off, swap to the parting tool, part off, done. Never turned off the lathe.

Now I'm really depressed.

 

[SLK001]

Right, MrWhoopee! For that one gear, and your assurance I can change the cross/carriage feed while operating, I could be really efficient. Picture it: Turn to diameter, flip the cross feed selector, face off, swap to the parting tool, part off, done. Never turned off the lathe.

Now I'm really depressed.

But you have to stop to check the final diameter, don't you?