I know those as engineers clamps, but according to Google it’s a toolmakers clamp. Can’t help with the bolt, sorry. I’ve only seen them in those clamps. You could probably replace the right-threaded one with a normal bolt or studding but I seem to remember they have a plain bit at the end.
What are the circled / highlighted bolts in these clamps called?
Also does this type of clamp have a name.
While procrastinating, I finally got round to trying to clean them. A first bath in acid has shown the bolts(?) are fucked and need replacing.
Cheers