What are these?

pomeridian
on 24 Jan 26 (21:40)
Updated 24 Jan 26 (21:43)

I am trying to figure out what these are! The key fits in the hole and when you crank it the space diminishes “inside” as if to hold something but there is a cross piece on the bottom which prevents a type or anything from held tightly. I’m flummoxed.

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mikefrommontana
on 25 Jan 26 (11:36)

This piece is meant for a plate base system using 11pt engraved metal plates. When locked up with other clamps and clips, it allows placing a player while only needing to move two of the clamps (or more if the plate is big). I do not recognize the plate system, though the clip looks like it might be Warnock.

pomeridian
on 25 Jan 26 (23:16)

Thanks Mike. I think I just found the aluminum metal plates which I originally thought might be some sort of fancy metal furniture!

The largest is 4 pica square and says THE PRTG. MxxH. CO. CIN. O. on the bottom.

Drew

mikefrommontana
on 27 Jan 26 (00:09)

The Printing Machinery Co. In Cinncinnati, Ohio manufactured the Warnock plate mounting system and was involved with the Sterling Toggle base system (the only system still made).