Quoins

Image from Brad Cornelius’s photostream.

via lawsonarchive
“In the past four centuries, very little tight logical change has been seen in the quoin, a simple item of composing room furniture used in preparing type for the press. The word itself, a variant of coin, has been used by printers since the 16th century. It is been discussed by the writers of printing manuals since Moxon’s treatise, Mechanick Exercises, first appeared in England in 1683….”
Read the rest here. Quoins are expandable metal or wooden wedges used by printers to lock up a form within a chase. More images of quoins can be found here and here.