Quoins are metal wedges that expand to lock type in an open bottom chase or a chase without locking thumb screws. Simply place the quoin between the set type and the base of the chase, insert the key and turn. The quoin will expand, locking the type into position. No. 0 quoin measures 3/8" x 1 3/4" when closed, 1/2" x 1 3/4" when expanded. No. 1 quoin is 5/8" x 1 7/8" when closed, 3/4" x 1 7/8" when expanded.