Router, mortise cutting jig.

[Derek Willis.]

This may be of help to some of you who want to cut mortises with a router.
First picture is a base with two pegs equidistant from the centre, place on the timber, twist until the pegs are against the edges and then plunge the router, do this from both sides if neccessary, if you have made this accurately then the mortise will always be in the centre.
The last picture is an additional piece to the jig, to be used when cutting mortises at the ends where the pegs will not locate. Cramp the frame to the timber using a spacer of the same dimension as the project piece, and carry on.
Derek.

 

[OPJ]

I like the simplicity of this jig, Derek, thanks for sharing.

 

[woodbloke]

I use the router to cut mortises. The easiest way to ensure that the mortice is central is to work from both sides with a slightly smaller bit so that if set up accurately a 6mm cutter will produce a mortise of say 7mm. Only one side of the mortise is cut each time and the setting on the fence remains constant. The other way is to set out the mortise by measurement which is a bit trickier but do-able, a trial run on a test piece is advisable - Rob