Components are squared and true
A mortise chisel is selected which is approximately one third the component thickness, and a mortise gauge pins set the same distance apart. The mortise gauge stock (fence) is set to position the mortise in the middle of the component's thickness.
The tenon shoulders are positioned so that the tenon remains a good distance away from the opposite edge of the mortise component
They are knifed in with a marking knife and try-square, on both the faces...
The tenon cheeks are gauged in from the face side, with the mortise gauge, on the two edges...
...and on the end
The mortise is gauged in from the face side of the mortise component...
...and it's ends knifed in
The mortise is chopped over a bench leg for support
The desired depth can be marked on the chisel with a pencil
Chop in the same way as the through mortise and tenon, except only from the one side, and to the desired depth
The tenon cheek cuts are sawn, staying on the waste side of the gauge lines
A knife wall is created for the shoulders by paring into the knife line from the waste side...
...after which the shoulders are sawn
The tenon thickness is checked...
...and fitted by either paring with a chisel,
or planing with a router plane or shoulder plane
The tenon is then cut to width, in order to fit the mortise length
With the tenon a good push fit for thickness and width...
...it's shoulders are cleaned back to the knife lines with a sharp chisel
The cleaned tenon can now be fitted in the mortise...
...and should seat perfectly at the joint line.
The fit should be snug, as demonstrated here.
Now watch the video: