I am still picturing a long square stock which would require one 90 degree rotation for the smaller pieces. Squeeze it between two long boards fastened to the waste board. All inside corners are cut by the bottom of the end mill (no taper bits, v bits, or ball mills). In the diagram below, the pockets extend over both sides of the square stock, cutting into the boards which would hold but nessary for the dado. The larger piece is a different issue (not included in the diagram) and would require milling stood up on its edge. Note this is a rough draft and may not be accurate.
I like this fixture a lot. What I’m concerned about is determining the XYZ work zeros after each rotation.
How do you ensure that the X Y (and Z I suppose) stays constant when rotating the object pieces?
Like I said, I’m still pretty new to CNC and I’ve mainly used the CA glue / blue tape method for holding down work pieces. What I have done in the past with symmetrical stock is to make a low-profille angle bracket either with clamps and t-nuts or with an angled L-shape or similar plastic piece.
For instance, I had to make one a bit higher and I made this small “strut” bracket on my Ender. I then aligned it with the t-slot and used it to fix a circular piece I was working on. I used a corner XYZ probe to get the X0 and Y0 and took the Z0 off the piece. I just used the known dimensions of the strut to calculate the zeros. (I did not design the strut – it’s a library – I just wanted to conserve filament).
I include the rectangular opening in my designs and center of the rectangle is zero. When I cut the rectangle I record its center in machine coordinates.
