pipe vise for square pipe?

[turnnut]

it is listed in DATAMP,

 made by Clark Brothers Mfg.  Belmont, N.Y.

[Bill Houghton]

Now that we've established that it is, indeed, a pipe vise and now that I've had a chance to think about it, I realize that it's a brilliant design: you can put the various standard sizes of pipe in and tighten up the vise with minimal work.  On a standard pipe vise, when you move from, say, 1/2" to 1-1/4" pipe, you end up turning the screw quite a bit; not so with this one.

[Chillylulu]

We use jaws with 4 contact points like that on production pipe fabricating machines,

  It makes sense, round jaws wouldn't cut in. Jaws on regular vises only contact in a couple of places. Multiple cuts are needed to fit variius pipe, tube, and conduit sizes.

Chilly

[Danks]

Another addition to this type of Pipe Vise from Mast Foos & Co's, Springfield Ohio. With additional capacity.

[Papaw]

That is COOL  Danks !

[Catch22!]

You folks are amazing.  I love the design.  How versatile can you get.

[Plyerman]

Those are some awesome old vises for sure. Thanks!