CNC Joinery for Ends and Edges

One of the final frontiers for hobbyist computer-numerical control (CNC) routers remains the ends and edges of workpieces where gantry-style machines struggle to create the crisp lines of traditional woodworking joinery, such as dovetails or box joints. This is because, by its nature, a spinning bit oriented perpendicular to the horizontal workspace of a CNC bed cuts a rounded profile on interior corners of workpieces. Workarounds that compensate often prove unsatisfactory, below.

This is not a problem for router tables or handheld routers. With both, you can reorient either the workpiece or tool so that the crisp-cornered profile of a bit, such as a straight bit or dovetail bit, intersects the workpiece face instead.

Several CNC manufacturers offer solutions that eliminate or circumvent the gantry-style CNC’s flat…