I have got a clamping tool and I don't recognise its purpose.  It consists of a pair of parallel beech timbers measuring 2 3/4" square and 25" long.  There are two very nice quality clamping screws with tee bars.  The threads are square section and about 1" dia. and screw through cast iron bosses fixed to the timbers.  Fully open the gap between the timbers is about 6"

My thoughts are that it has something to do with the old letterpress printing and was used to clamp the diecast lead lettering together before placing into the printing machine.  A clue is that some black staining could be printers ink.

Any ideas will be most welcome as I have no use for it and would like to pass it on to someone who would appreciate a quality tool , the purpose of which I do not know.

Regards to all , Pete

Kinda hard for me to visualize.  Could you get a picture of them?

I would have to see a picture, but it sounds like a flask clamp used in cast iron foundry work.  I have had a few that were that style, as well as some more modern all metal ones.

The description sounds like it may be one of these:
https://www.google.com/search?q=wood%20clamp&oe=utf-8&rls=org.mozilla:en-US:official&client=firefox-a&um=1&ie=UTF-8&hl=en&tbm=isch&source=og&sa=N&tab=wi&biw=1143&bih=457&sei=w5DSTs_wEqzXiAL2kfzuCw

Only much bigger than most??

It doesn't sound like any printing equip I've seen. What I've seen were just a square or rectangular frame made of about 1 inch square material. After typesetting any slack was taken up by lead shimstock. That was for Heidelburg presses which I think was one of the commoner presses.