The diagonal mortises were much more work than I expected. That plus a busy work schedule and holiday made for slow going. It took a very long time to chisel out the sharp points of the mortise and the hard oak was tough on my chisels. While the guide I made worked pretty well for the finally trimming, I found that it helped to use a small bit and drill out the four corners freehand to save a quite a bit of chopping. My drill went outside my layout line in the photo, but this will be covered by the tenon’s shoulder so it is fine.
I also found that a small wooden tenon was helpful to test to make sure that all the waste was cleared and the the mortise walls were flat.
I still need to cut mortises for buttons and for the top of the legs to fit into, but next I will cut the tenons.