I've been working on the joinery for the upper rails of the cabinet stand. There aren't too many option for joinery for this cabinet stand since the stand is supporting the weight of the cabinet as opposed to coffee table legs for example. I decided on conventional mortise and tenon joinery since it is time proven and has the benefit of being a strong, mechanical joint and capable of any racking forces. My procedure is to mark out the mortises in each of the legs. Each of the legs will have mortises in two adjacent faces to be able to join a short and long apron rail. I also select which side of the apron rails I want to face outward at this point as well as orienting the legs in their most aesthetically pleasing faces.
The mortises are offset from the top of the legs some distance to maintain sufficient solid wood between the end of the tenon and the top of the leg. To offset the resulting, shorter tenon I offset the bottom of the tenon a smaller distance to the bottom of the apron rails. This allows for a wider tenon than if I had made the tenon symmetrical. I typically rough cut the tenons slightly larger than the mortise and then trim them to fit tightly into its mating mortise. Measuring and marking cannot be stressed enough for this operation, the final dimensions of the stand need to be exactly the same as the bottom of the cabinet in my design. The tenons of two adjoining apron rails meet in each of the legs at a right angle. To accommodate this within the mortise housing I saw a 45 degree angle out of each of the tenon ends. The result is two of the rails meeting at 90 degrees within the mortise housing.
The markings for these cuts can be seen in the top photo. In the bottom photo, I test fit all the tenons and mortises and can now proceed to the next phase of creating the bottom stretchers for the cabinet stand. I also have not cut the legs down to their final length quite yet, I will also be doing this next once I decide on a final height for the cabinet.