I have these. I bought a set a while ago when they were reduced. I’m not that keen on them at all. They do the trick but they’re extremely fussy and take a fair bit of fiddling about to get them to grip well. As Ken mentioned, you’ll want to protect the piece being clamped or it’ll get heavily marked and require a lot of cleaning up.
I think most of the problems I have with them could be remedied with a few alterations, similar to what Paul does with his aluminium clamps. A long piece of ply to strengthen the main bar and pads on the jaws. I’ve waxed the main bar with paste wax as well which helps the jaw move with less fussing but it’s still a bit of a pain.
Rutlands are great for clamps when they have sales on though. I want to try some of their F clamps. They’re a bit more expensive but are cast iron so should be much stronger.
thanks george and ken i have some of the ones paul uses but i thought these had longer faces and wouldn’t require ply pads i think i’ll stick to the masters recommended type as they seem to work well so far