Im attaching a pic of my test cuts for a mortise and tennon joint. This is just a test piece, no real world application, other than dialing in my new lowrider. It is a mortise and tenon, each of which I drew at 38mm x 19mm. Both parts came out the same dimensions.
The pic shows the target dimensions and actual cut dimensions. The white paper shows how the part is oriented on the machine.
As you can see, the overall width of the part (50mm) is on target for what I would expect with this machine. I’m happy with that.
The Y dimensions for the both the mortise and tennon is also acceptable at 18.9mm
The overall length of the part is 1mm too short (119mm) which is too much for such a small part.
Also Im concerned about the mortise and tennons.
The tennon is about 0.5mm oversize, and the mortise 0.5mm undersize, causing interference.
I would expect a tight fit between these parts, and maybe even a light sanding to get them to fit nicely, but that is too much interference.
The fact that male portion is oversized and the female part undersize by about the same amount, and that the other dimensions are acceptable, makes me wonder if this is some sort of tool size compensation problem or a software setting that Im missing.
The material is 3/4" cedar (very soft), and was cut at 2mm axial DOC (10 passes) and 400mm/min feed. Cutter is 1/8" single flute carbide, brand new. Cut quality is clean with a few tool marks on the last few passes.
I did not use roughing/finish passes. I did a simple 2D contour cut. Post processor was the fusion 360 MPCNC from flyfisher605.
Obviously I could compensate and make the parts fit together by altering the drawing, but I would like them to be closer to “as drawn” dimension, which I know is obtainable because of the other acceptable dimensions in the part.
Any suggestions of what to check?