Accurate Repeatability

I began a small project this week that I hope to have completed by Christmas. The design is based on a square block of wood with four slot mortises routed at each corner. A larger circular feature is routed on the opposite face of the block. There are nine blocks in all.

In total then there are thirty-six slot mortises to route. Repetitive accuracy is a requirement so the use of the CNC router was a natural choice for machining the mortises.

The design solid model served as a starting point for geometry on which to base the slot mortise tool paths. The following segment of machine code represents a single pass at depth. There are multiple passes for each slot, and each pass plunges into the block by a fixed distance until the final depth is achieved.

F14.0
G00 X0.5938 Y0.5313 Z0.2000
F11.0
G1 X0.5938 Y0.5313 Z-0.0620
F14.0
G01 X1.7813 Y0.5313 Z-0.0620
F14.0
G00 X1.7813 Y0.5313 Z0.2000

The two left mortises both top and bottom are routed together, and since the block is square and its features symmetric, it was simply rotated to produce the remaining mortises on the opposite side of the block. Doing it this way allowed the block to be clamped to the table on one side while routing took place on the other.

The routed mortises will accept tenons from four legs that support the block as a platform of sorts. It should begin to be apparent what this project is all about.