Automatic stops on manual lathes

partsproduction · Aug 14, 2018

My brother saw the automatic stops on one of my lathes today and mentioned them, I said I'd never used them, and doubted that most machinists do.

This made me wonder if I'm right. Am I missing manual lathe Valhalla? One of my lathes even came with cross slide stops, which I promptly took off as the mechanism was in the way.

thermite · Aug 14, 2018

partsproduction said:
My brother saw the automatic stops on one of my lathes today and mentioned them, I said I'd never used them, and doubted that most machinists do.

This made me wonder if I'm right. Am I missing manual lathe Valhalla? One of my lathes even came with cross slide stops, which I promptly took off as the mechanism was in the way.

Time was, labour was cheaper, CNC had not arrived, some work didn't fit a little Hardinge, nor a firm own a Gisholt, Warner & Swasey, etc - and ordinary manual engine lathes, even "toolroom" lathes were actually used for unit production in significant volume.

Stops - GOOD ones - were essential for that. A "setup man" or team leader would do the arranging and test it to insure parts hit spec, and towards the edge of the range that allowed for a bit of tool wear.

A bored housewife at min-wage might then make the parts for several hours, periodic QC indicate when the tools and setup needed attention. Skilled setup man was off working-up another one in the meanwhile. If anybody sat unproductive for a spell, it was the lesser-skilled and lower-wage person.

Common as all get-out back in the day.

G'Mum, not even five feet tall, ran a big old capstan lathe to put the pointy ends on War One Royal Navy artillery projectiles. Proud as punch about it, too!

rons · Aug 14, 2018

partsproduction said:
My brother saw the automatic stops on one of my lathes today and mentioned them, I said I'd never used them, and doubted that most machinists do.

I use my left side stop when threading from right to left.

partsproduction · Aug 14, 2018

I use my left side stop when threading from right to left.

An automatic half nut lifter?

thermite · Aug 15, 2018

partsproduction said:
An automatic half nut lifter?

Only if yer jockstrap is torn?

The stops on an HBX-360-BC are more sophisticated, yet, and exceedingly precise.

OTOH it doesn't have a conventional leadscrew, convention half-nuts, nor anything ELSE "conventional" if there was any possible way to do weird instead!

Schaublin does some similar trickery, but somehow makes it seem AS IF it were "conventional".

Guess that's "diplomacy"?

drom68 · Aug 15, 2018

I use them. They are very helpful and don't take much to set them up. I use them during long cuts and / or repetitive pieces as it allows me to go do other work. I use them for roughing in only.

The Monarch 10EE I have has an electronic lead screw reverse with an adjustable stop. Again I use that from time to time. I also use it for specific threading jobs.

Cole2534 · Aug 15, 2018

partsproduction said:
An automatic half nut lifter?

Mine kicks the lead screw (or feed rod) into neutral. That with the single dog clutch, crossfeed stop and apron mounted reverse make for some smooth threading, even to specific depths internally.

GregSY · Aug 15, 2018

I wish my lathe had one...they are great for letting something cut while you sweep the floor up. At present, my carriage will automatically stop when the vibrations from the chuck beat the toolpost enough.

thermite · Aug 15, 2018

GregSY said:
I wish my lathe had one...they are great for letting something cut while you sweep the floor up. At present, my carriage will automatically stop when the vibrations from the chuck beat the toolpost enough.

Sheesh.. "toolpost".. Texians gone wimpish? What next?

Bigger motor and a magical "VFD" will sort that little problem, let the edges of the compound and the chuck jaws earn their damned rations!

"Teamwork" y'see. Nobody gets a free ride..

crossthread · Aug 15, 2018

I built a threading stop for the cross slide of an old SB I have and I really like them. This is one of those two way stops that you adjust to stop the cross slide in both directions. You back out the cross slide, use the compound to put on some cut and then run the cross slide back in to the stop. Really helps a lot when you are threading because you don't have to worry about losing your place. It is very simple. Locks to the dovetail with a setscrew and has an adjusting bolt you put in the backside of the cross slide. The threaded hole was already there and may have been for that purpose. My new lathe does not have one but I use the old SB for a lot of threading because I am very comfortable with it.

rons · Aug 15, 2018

partsproduction said:
An automatic half nut lifter?

I wonder how the Hardinge Brothers would answer that...

DDoug · Aug 15, 2018

My Sheldon r-15 has both (cross slide one is missing the plunger) but the
Long feed with both hard stop (micrometer dial) and feed trip off is nice for internal blind boring. I let the feed trip off, then manually feed extra to the hard stop.

W&S and most other turret lathes have stops that index, as well as stop the feed.

Very nice when running carbide, and chips are flying all around.
Pull the feed lever up, and step back.

And, you have time to step to the right, and engage the turret feed (running a boring
bar for example).
Both will run and then trip off by themselves, no crashing.

thermite · Aug 15, 2018

rons said:
I wonder how the Hardinge Brothers would answer that...

With a price quote, of course!

TDegenhart · Aug 15, 2018

I have a 12CK Monarch that has automatic carriage feed stop. Its accurate to a few thousands, more than enough for my needs.

Tom

Terry Keeley · Aug 15, 2018

Emco Super 11's have them for both longitudinal and cross travel, works great!

Ray Behner · Aug 15, 2018

Like Digger Doug's Sheldon, mine has long and crossfeed auto kick outs. My 20" American does as well. The Sheldon s good, but the American kicks out dead nuts every time. Yes, I use them all the time.

sfriedberg · Aug 15, 2018

There are stops and there are stops. There is a type of carriage feed stop where a olive-shaped cam is locked onto on a prismatic shaft below the feed shaft (the prismatic shaft rotates so you can select from several pre-set cams) and a lever on the carriage bumps the cam to disengage the feed. This type is common on generic import lathes, and it's terrible! You'd be lucky to repeat within 0.050", which means you can't use them to cut to a shoulder.

DDoug · Aug 15, 2018

sfriedberg said:
There are stops and there are stops. There is a type of carriage feed stop where a olive-shaped cam is locked onto on a prismatic shaft below the feed shaft (the prismatic shaft rotates so you can select from several pre-set cams) and a lever on the carriage bumps the cam to disengage the feed. This type is common on generic import lathes, and it's terrible! You'd be lucky to repeat within 0.050", which means you can't use them to cut to a shoulder.

As I indicated in my post, you let it trip out, then HAND feed until you hit the stop, repeats nicely.

There are qty (2) things going on.

TDegenhart · Aug 15, 2018

I modified my HLV-H copy, a Victor 618EMS,to have automatic carriage stop. I use the rod that is normally for controlling the carriage direction during threading. I mounted a limit switch that senses the position of of the control rod. The control rod stop block is set to where the carriage is to stop with control lever all the way to the left. When the carriage hits the block, it moves the control rod slightly to the left. This opens the N/C contact in the limit switch which interrupts the 120v to the carriage motor.

Tom

partsproduction · Aug 15, 2018

This type is common on generic import lathes, and it's terrible!

In fact that is the type my brother pointed out, only, I never got as far as testing for accuracy. This lathe also came with a micrometer hard stop to follow up to, as digger mentioned.
This duplicates the normal DRO method I've always used, power feed to within such and such a distance, maybe .020", kick off the feed and use the handwheel to move up to my zero. I never thought about this much as to whether others do the same or not.
Threading is another matter, it seems to me that a stop could be made to trigger the half nuts open and simultaneously trigger a spring loaded retract of the cross slide.
I think both half nuts and cross slide operations would need to be spring loaded for it to work, and sure enough it would prove too complex at the exact wrong moment near the end of many operations on a large shaft. Murphy there.

I built a threading stop for the cross slide of an old SB I have and I really like them.

I've seen somewhere a simple eccentric with a lever, turning the small lever towards you it moves the cross slide out, maybe .200", and turning it the other way moves back to your threading start point. I still think that's slick. If it pushed against a spring going in and had a sear to release it that would work with a stop tripped half nut opener.

Automatic stops on manual lathes

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