Success! … kind of. Holes are good, but not low corner cuts (due to chain sag). It’s better than most machines, I suspect, but not anywhere as good as I had my Classic.
I’ve been doing calibration for the past ~6h nonstop. I had to invent a calibration approach in order to achieve the same accuracy I had with the classic. My “success criteria” is being able to cut a 1" border off a 4x8 with 1/16in tolerance. I was able to place holes more or less accurately, but they drifted by about 1/4" in the low corners.
I’m planning to make a calibration widget out of this, as I’ve already been investigating CNCjs in anticipation.
@madgrizzle I downloaded their Makerverse software and discovered than in the latest version, they are indeed changing $84 and $85 (not $100 and $101).
Also, the hint about the trig was great. I ended up measuring from the last gear on the bottom of the sprocket before the chain becomes straight (for the motor height & motor width measurements). AFAICT, this creates the appropriate triangular shape.
The hard part is dialing in the motor offset “just right.” If it is wrong, it causes bowing in the Y-axis, so the middle part is higher/lower than the sides. If the center bows upwards, the motor height is too large (and vice versa). I basically used the same 6 holes cut by the Holey calibration, but instead placed them 1" from the border of the stock (as I explained here, with the idea of “overclocking”). Simply diving the expected vs. measured distances between the holes was enough to zero in on the correct scale factors. My early mistake was being off by ~5mm in the motor height and trying to dial in scale first.
My sled is at 26 lbs… I am getting a tiny bit of rounding (chain sag) in the lowest 1" corners when cutting (and therefore dragging) right on the corner, but nothing too bad (1/4" rounding at worst).
Time to try using the new 1/8" bit to cut something…