Odd old tool measures 7" long pincher-nipper-tong. No maker marks nice locking handle.

I can see it being used as a soldering clamp.

 Neat tool Never seen one.

We had something like this tool on the list not long ago, didn't we?
I sure remember the locking system.

 I posted a pair of pliers with a similar locking system but assume these have specific use.

I tend to agree with BruceS,soldering ,brazing or welding

I was thinking about using this to pull, lift sheet metal, that handle bent down would make a good pull point.  But clamping for soldering makes real good sense, just why jaws instead of points?   Be a bigger heat sink, wouldn't it?