the.com/mortiser
The chisel that bores square holes because round ones were too easy.
square holesDrill bit spins inside a four-sided hollow chisel
old craftCuts the mortise half of mortise-and-tenon joints
no glueJoints predate adhesive, holding furniture for centuries
chain versionIndustrial models use spinning chainsaw-like cutters
name originMortise comes from Arabic for fastening point