Centering tail piece?

[tundrawolf]

In all honesty, you completely lost me with the discussion of welding 2 pipes in a lathe using the TS for pressure. Upon reading that, I posted up lengthy (but hopefully clear) description of a cheap/dirty way to align the TS before you damaged your lathe.


Ray

I damaged my lathe?

I probably did?

I don't know what to do?

 

[benmychree]

In my and many others opinion, welding should NEVER be done in the lathe, the spindle bearings may be damaged; it is very poor practice to do so.

 

[brino]

@tundrawolf

To be clear, the guys are concerned that you may damage your lathe by welding things held in it.
How?

1) if you put your ground lead on the lathe base and you weld two parts held in the headstock and tail stock chucks, then all that welding current thru the ground lead MUST go thru the spindle bearings, chuck jaws, some thru the ways to tailstock interface, etc. You could seriously damage the headstock bearing or do a little accidental welding on one of those interfaces.

2) Even if the ground lead is connected directly to the work-piece, the inevitable weld spatter on the ways can wreck them

Can you instead use the lathe to turn a mandrel that both tubes can be slid onto to align them and then weld the two tubes together while on the mandrel? (far away from the lathe). Even if the two tubes have different inner diameters, you could turn a mandrel with a step/shoulder to account for this.

As for the welding, I think you are correct about trying to balance the heat in an attempt to minimize warping. Start with one tack weld, then quickly do another 180 degrees away, then a pair 90 degrees to the first two.

What welding processes do you have access to?

-brino

 

[epanzella]

I would hold the 2 pieces together with a threaded rod going thru the middle with cleats on both ends. Leave the lathe out of it.