Mortising & hollowing

Mortising and hollowing are selective subtractive operations that create closed or semi-closed cavities in the material: mortises, slots, niches and joint seats. The chain or chisel mortiser drives a toothed chain or a reciprocating-motion tool to excavate precise rectangular pockets—the mortises—into which the tenons of frames, chairs and timber structures are inserted. The hollow chisel or vertical-column mortiser, by contrast, drills deep with a rotating tool to produce bearing seats, threaded-insert housings or pockets of any shape. In both cases the geometry of the cavity is determined by the tooling and the feed, not by a CAM path: these are simple yet highly dimensionally precise operations, often impossible to replicate by any other means without resorting to CNC milling. In the maker context they are essential for structural woodworking and for producing mechanical components with precise mating seats.