With the first set of mortises in the corner posts complete, it is time to move on to the second set.
As I started cutting the test pieces it became apparent that it is critical to use the exact actual size of the posts or the end mortises and rabbet for the panel wont line up. The legs are a nominal 1.5″ wide but after sanding are actually 1.45″ wide. This is enough to cause the end decorative piece mortises to intrude on the rabbet for the end panels.
Looking back I should have cut all of the rabbets with the mortises for the end pieces and not with the first set of mortises for the front and back supports. This results in some extra hand work and there was one leg that had to be redone all together.
When manually making the rabbets and mortises, my setup always take into account the fact the at the pieces are not EXACTLY uniform and the best reference edge is used to minimize error and achieve uniform joints. On the dresser the natural reference edge on the corner posts is the inside corner.
Additionally the rabbets should not be done as a single pocketing cut with the CNC router but rather first a skim cut should be made to prevent blow out or chipping along the edge.
Video of the second set of mortises being cut: https://youtu.be/G0lsWLeAlKk . The photo below shows the corner post after the second set of mortises has been cut. The saying on my coffee cup has never been more true.
Now we move onto cutting tenons for the end rails. My favorite way to cut large numbers of tenons is to use a stack dado set on the radial arm saw.
This is the primary task for the smaller 10″ radial arm saw. The large one (14″) is used almost exclusively for cross cuts. Note that both share a common fence and top system. Radial arm saws can be purchased for almost nothing nowadays. The big one was salvaged from a school and purchased for $50 (and then completely overhauled).
Double check that the saw is cutting exactly squarely. This is best done by taking a test piece that has been ripped for exactly parallel sides and a square end. Then make shallow rabbets on each side. If the cuts line up on both edges you are square. This is quite sensitive and uses less stock than the normal cut and clip technique. You can see the test piece laying on the top between the saws.
The stock must be of uniform thickness. The best approach is to ensure that all of the stock was planned in one batch or better yet sanded to final thickness in the drum sander as we did with the legs. It takes a bit of fiddling with the height adjustment to get the tenon thickness right.
I have added a digital readout to the height adjustment of the radial arm saw to make this easier . After each test cut adjust the height by 1/2 of the thickness correction (e.g. if you want a 0.25″ thick tenon and the test piece measures 0.28, adjust the blade down by 0.15″. However always be sure to finish the adjustment by raising the blade to take out any play in the mechanism which would result in decreasing thickness cuts as the arm settles down.
The cuts are all made with a stop block to ensure repeat-ability. Note that the sacrificial wood stop block is notched on the bottom to allow room for sawdust. The grey stop block on the left holds the position. If only using one block, a spring clamp would not be sufficient. Then I would be using 2 hand screw clamps as using only one will typically slip on repeated cuts.
Here is one of the bottom rail tenons being cut for thickness.
Here it is being cut for height.
The mortises were cut with a router and rather than squaring all of them off with a chisel, I typically prefer to round over or bevel the tenons. THe base of each tenon corner is nicked with a pull saw and then a couple of strokes with a chisel removes the rest as seen below. This is one of the top end rails.
The end rails now need notches for the decorative frame work and this is done again on the CNC router.
Here are the ends test fitted.