A quoin is a device used to lock printing type in a chase in

letterpress Letterpress printing is a technique of relief printing. Using a printing press, the process allows many copies to be produced by repeated direct impression of an inked, raised surface against sheets or a continuous roll of paper. A worker com ...

printing. Quoins are pairs of wedges, facing opposite directions. A wrench or quoin key forces them together.

References

Letterpress printing Relief printing {{Typ-stub