mortaise

A mortise is a rectangular cavity cut into a workpiece, typically wood, to receive a corresponding projection called a tenon. The mortise and tenon form one of the oldest and most durable wood joints, used in furniture, cabinetry, and timber framing. The term is commonly spelled mortise in American English and mortice in British usage.

In joinery, the mortise accepts the tenon to create a strong, right-angle connection. Common variants include the through mortise, which runs completely through the workpiece; the blind (or stub) mortise, which does not exit the far side; and the stopped mortise, which terminates before reaching the edge. The corresponding tenon can be plain, haunched, or otherwise shaped to suit the joint and load requirements. A snug or slight clearance fit is typically chosen to allow glue and wood movement without excessive looseness.

Cutting methods range from traditional chisels and mallets to more modern equipment. Tools such as a mortising chisel, hollow-chisel mortiser, drill press, or router can be used to remove material and form the mortise walls. Accurate marking and squareness are important to ensure proper alignment and flush surfaces.

Fitting considerations include tolerance, wood movement, and the use of adhesives or mechanical fasteners. Mortises may be reinforced with pins, wedges, or drawbore pins for added strength, especially in timber framing. The joint’s geometry and fit determine its load-bearing characteristics and ease of assembly.