chase
A rectangular steel or iron frame into which pages or columns of type are locked for printing or plate-making.
chase: the steel cage that holds type for the press
A chase is a rectangular steel frame, typically cast iron or fabricated steel, that holds composed type or printing plates rigid during the presswork. In letterpress printing, the chase receives pages of type arranged by the compositor, secures them with quoins and furniture, and transfers them safely to the platen or bed of the press. Without the chase, individual metal sorts would scatter under the force of impression.
Chase sizes follow traditional standards tied to press capacity. A foolscap chase might measure 15 by 10 inches (inside dimension); larger newspaper chases run 48 inches or more on a side. The frame itself is typically 1.5 to 2 inches thick at the walls, with a flat bearing surface on top and bottom. Cast iron chases are brittle and prone to breakage if dropped; fabricated steel chases tolerate rougher handling. The interior has a smooth, level floor to receive the type.
Securing type in the chase
Type is packed into the chase using wooden or metal furniture (strips filling blank space) and quoins, which are tapered locking wedges tightened by hammer blows or mechanical leverage. The aim is zero movement: any give under pressure causes blurred impression and uneven inking. A loose chase ruins the job. Makeready, the process of backing out high or thin spots, requires the chase already locked on the press, making tight initial packing essential.
The chase is held to the press bed by a clamp system or bolts, depending on press design. Platen presses, cylinder presses, and flatbed presses all use chases, though automated machines have largely replaced them. Hand-fed presses still demand a skilled operator to position each chase and verify lock-up before running.
The term 'chase' derives from Old French 'chasse', meaning a frame or case. In gravure and lithography, related metal or wooden frames called beds or masters serve analogous roles. The chase itself holds no ink; the type or plate does. A worn or warped chase produces uneven impression across the entire print run, so foundries and print shops periodically true their chases by dressing the working surfaces on a surface grinder.