Cutting Mortises for the Stern Chair

Here is how I cut the mortises on the back of the Stern chair.  

My Domino would not cut a mortise wide enough so I made a jig to accurately overlap two Domino slots.  It took quite a bit of trial and error to get the hole spacing on the jig just right.

The jig served as a reference fence for the Domino

The centre line on the jig marked the centre line for the mortise

The outside hole on the jig marked the location for Domino pin to cut the first slot

First mortise complete

The inside hole on the jig marked the location for the 2nd

 plunge cut

The mortise is now complete

The walnut tenon fits perfectly