Ed Minch wrote: "Wait til you discover the true range of these things.  I even
found one that only tightens and does not loosen - made for assembly lines where
they
only tighten and don’t loosen."

I've got one like that, another inherited tool (though not one I use much any
more), and a favorite because the action is so sweet and it is conveniently
small.

It has a patent date of Oct. 7, 1884. And a mark "Decatur Coffin Co."

Not sure "assembly line" is quite the right term.

Tom Conroy
Berkeley