Download the Fusion360 model and take a bit of time to review the mechanical design of the machine so you can understand how all the parts fit together. The Circuit Graver is color-coded; brown for frame, grey for X/Z axis, ivory for R axis, and green for Y axis. The X and Y axes ride on MGN5 linear guides driven by lead screws and NEMA17 steppers; the Z axis is a flexure, lifted by a servo and pushed down by another flexure; and the R axis is constrained by a pair of 6803 thin-section bearings and driven by a NEMA14 stepper. Most of the parts are held together with M2, M3, and M4 hardware; I tried to keep this to standard assortment sizes (8-20 mm in 4 mm increments), but the machine does require a few longbois.

I printed all of the printable parts in normal PLA at 15% infill and 5 perimeters. Importantly, the print orientation for many things (like the ten flexures used in various parts of the machine) is critical for mechanical performance; this ends up coming at the expense of print production optimization, so get ready for a good amount of support material removal. I ordered the aluminum plate with the requisite tapped holes (see CAD model for which ones) from an online vendor; you could probably mill or waterjet it yourself if you have the fab infrastructure, but some of the locating features are precise enough that I'd avoid bandsawing it.

A lot of the parts are tight fits and will need a bit of hand work with a file, sandpaper, and perhaps a deburring tool to fit together well. Go slow and be gentle, and if needed, add offsets to surfaces to suit the quirks of your 3D printer. In particular, the bores for the R-axis bearings need to be cleaned up due to non-optimal print orientation, and the big blind mortise and tenons that fit the frame together needed a bit of work too.

Print out the dial indicator holder for the MGN5 carriages and sweep the rails in place. I was able to get to <1 tick of parallel on a 10 micron graduated test indicator; not quite Hiwin's spec, but good enough for low speed / low load operation (and a test machine! it's just a prototype, it might break). Cut down the lead screw if necessary and slide it through the 608 skate bearings, locking collars, and lead screw nuts. Preloading the lead screw against the locking collars is finicky; I did this manually by pushing the whole machine down on my desk and carefully tightening the collars with a hex wrench. A bit of axial preload on the 608s is key; without it, the nifty anti-backlash flexures aren't particularly useful! Once the axes are assembled and running nicely, hit the MGN5s with a light PTFE-based oil and gob some lithium grease on the lead screws. Adjust the lead screw nut preload so you can't detect any backlash but are still able to backdrive the assembly.

Install motors! Add belts! Tension them! Make them turn, either using modularthings boards or a COTS 3D printer G-code ingesting device! Okay, I need to add more detail here, so if you get to this point and are stuck, drop me a line.