Thread: Simple rpoter mortising jig.

Attached a diagram of a very simple jig I use. The two jig parts, (Jig A and Jig B) fit together and register on the face edge where the mortise is required. The two jigs are clamped at X-X and Y-Y. Distance C is determined by the rouer and bit used. Jig A is positioned such as to set the end of the mortise. Jig B is then adjusted to give the length of the mortise. Once set, a reference line is drawn across both jigs and workpiece. The router fence runs on face Z, and is adjusted to centre (or offcentre from the face side) the mortise.

Setup is best done on scrap of same width as the workpieces, by trial and error.

Subsequent mortises only require the reference line to be drawn across the face edge of the workpiece, at one end of the mortice. The Jigs are put in position, the reference lines on the jigs aligned with the line on the workpiece and clamped.