Using a lathe as a rotary weld positioner ?

[DAVE94LIGHTNING]

How would I connect a good ground clamp to the lathe setup if I intend to use it for welding tubing? Thank you

 

[Dave G in Gansevoort]

A copper bar attached to the ground and laying on the tube, but not touching any part of the lathe. You don’t want any current going through the bearings of the lathe. The bar will rest on the tube and the other end supported on something wooden like a step ladder.

 

[Old Man Roger]

Are you welding over the bed, or what’s sticking out of a steady rest?

 

[Firebrick43]

Quickest way to destroy a set of precision headstock bearings is to use a lathe as a welding positioner.

 

[slowtwitch73]

You can just put your clamp straight on the work with clamp handles down so when the work rotates, the handle jambs against the tool post/carriage.. the tube will spin in the ground clamp jaws unless you're working on something large dia.

 

[Old Man Roger]

You can just put your clamp straight on the work with clamp handles down so when the work rotates, the handle jambs against the tool post/carriage.. the tube will spin in the ground clamp jaws unless you're working on something large dia.

If the work wasn’t going through a steady rest, I was going to recommend something similar. Maybe, instead of just clamping onto the steady rest, he could use a length of braided copper wrapped around the work? Pinch it at both ends with the ground clamp. That way if it happened to somehow catch, it would just get pulled out of the clamp.

I wouldn’t weld at all on my lathe, definitely not over the ways, but maybe he has one he uses for grinding and abusing?

 

[no704]

Have to slow it way way down first.

 

[Oregon rock crusher]

I have an old Oster pipe machine that gets tasked with that kind of work. It cost next to nothing. I tried a spray weld set up on it once for shaft build up. What it lacks in precision it makes up for in toughness. I suppose if you have an old beater lathe and get a helper to spin it by hand. Ed.

 

[Steve from Socal]

An old plain bearing lathe or a beater with a vfd to control speed. As mentioned the precision bearing in a lathe headstock will be subject to damage. Insulating the entire weldment from the lathe with wood, rubber or plastic would be the other way to do that. A wood mandrel?

 

[DAVE94LIGHTNING]

Thanks for all the good info. It sounds like too much of a pain to use the lathe overall hence why no one probably does it. I'll build or buy a dedicated weld positioner for the tubing work instead.

 

[dutchgray]

Quickest way to destroy a set of precision headstock bearings is to use a lathe as a welding positioner.

This has recently happened near me, some car modifiers had borrowed a small Colchester lathe off the engineers in the building next door and used it for all sorts including welding, the Gamet taper roller spindle bearings are no longer high precision, they definitely weren't aware how much a set of those cost.

 

[Firebrick43]

This has recently happened near me, some car modifiers had borrowed a small Colchester lathe off the engineers in the building next door and used it for all sorts including welding, the Gamet taper roller spindle bearings are no longer high precision, they definitely weren't aware how much a set of those cost.

Those style of bearing the ones that are spring loaded that colchester used?

If so I didn’t even think the were still available

 

[scooby074]

If this lathe is any good, dont!

 

[dutchgray]

Those style of bearing the ones that are spring loaded that colchester used?

If so I didn’t even think the were still available

Not sure, I haven't ever had one apart myself, Gamet and Colchester were both part of the 600 group in the later period so it was the obvious choice for their spindle bearings, being possibly the best made as well. They used to match the rollers to within 3 millionths of an inch on diameter in any given bearing, lots of good lathe makers used them, usually a double row front bearing that was pre set and a single row in the back. My first 13" DSG also had a "normal" precision ball bearing in the middle of the spindle tube just to make it a little better

They can be found if you need them, or at least people tell me they can, at great expense, but replacing the lathe for one with good bearings will likely be cheaper.

 

[gregs]

An old welding / fabrication shop nearby had an old, flat belt lathe they used for building up parts by welding. I am sure it was just plain bearings and something no one would want. Since it was so old and originally driven by an overhead belt system, they got creative. This was probably late 70's early 80's before VFD's where common place. What they did was to use a 4 speed car or truck transmission mounted above the headstock and various pulleys and belts to run the input with an electric motor and output to the spindle. It sorta looked like a contraption but seemed to work well for what they used it for which was mostly repairs of farm equipment. They had heated up and bent the shifter handle down along the side of the transmission which put it right above the headstock. I always thought it was a pretty good use of what was basically scrap iron.

 

[Old Man Roger]

Hey! Easy with the scrap iron talk.lol Mine was originally run by a water wheel, it was upgraded to electric motor in 1914.

 

[gorilla]

Do you ever watch those Pakistani guys on U- Tube? They seem to do it all the time. I often wonder if they have a carbon ground brush built into the lathes so that the bearing aren't ruined.

 

[NUTTSGT]

How big of tubing are we talking ? I've watched people use a set of Vee roller stands and a second person to slowly rotate the work

 

[dutchgray]

Do you ever watch those Pakistani guys on U- Tube? They seem to do it all the time. I often wonder if they have a carbon ground brush built into the lathes so that the bearing aren't ruined.

I think most of those lathes are already ruined before anyone welds things in them.

 

[cannuck]

This has recently happened near me, some car modifiers had borrowed a small Colchester lathe off the engineers in the building next door and used it for all sorts including welding, the Gamet taper roller spindle bearings are no longer high precision, they definitely weren't aware how much a set of those cost.

I would never weld and only in extreme case with careful protection weld or grind in my lathes.

VEVOR Rotary Welding Positioner 50KG, 0-90° Welding Positioning Turntable Table 0.5-6RPM 120W, with 12.4 Inch 3-Jaw Lathe Chuck & Welding Torch Stand Holder for Cutting, Grinding, Assembly, Testing | VEVOR CA

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Bought this Vevor rotary positioner about a year ago and it remains in the shop as used often. For the money works well. I had to build some jaw extensions as I often do aluminum tanks and filter housings.

 

[mikegt4]

My neighbor had several pottery kick wheels that he acquired for free from a retiring art professor down the road. I asked about getting one but he forgot and sold them for scrap. I though it would make a good rotary positioner.

 

[no704]

 

[welder4956]

How would I connect a good ground clamp to the lathe setup if I intend to use it for welding tubing? Thank you

Hang a piece of braided copper over the tubing and attach the ground clamp to the braided copper: https://www.amazon.com/AC-DC-Supply-Copper-Grounding/dp/B07S9GZRN9?tag=atomicindus08-20

 

[Old Man Roger]

Exactly what I was talking about.

 

[sqznby]

A company I worked for used an old LeBlond lathe for some of their vessel's components.
It was in use for 30+ years making the same parts.

 

[Old Man Roger]

A company I worked for used an old LeBlond lathe for some of their vessel's components.
It was in use for 30+ years making the same parts.

I don’t think anyone was saying it cant be done, just that’s it’s not good for the lathe. Plenty of people use lathes for grinding, but you wouldn’t want to do that to a good lathe.

 

[sqznby]

I don’t think anyone was saying it cant be done, just that’s it’s not good for the lathe. Plenty of people use lathes for grinding, but you wouldn’t want to do that to a good lathe.

Right right right, don't mind me I'm a little late to the game and just buzzed through it