Gmax bed leveling system

the gMax 1.5+ printers don't have a way to physically level the bed, these parts give this printer this much needed system (at the expense of ~1 inch of Z-height).

Aside from the 3D printed parts, you will need:

12 M5x10 socket head screws
4 M5x40mm hex head screws
4 M5 flat washers
16 M5 nuts
4 M5 nylon insert lock nuts
4 compression springs that with diameter just larger than the M5 shaft.

Print these parts:

4 elevator shafts (each corner is a unique part)
4 elevator carriages (all identical)
4 corner lateral guards
4 knurled knobs

The design takes advantage of various pre-punched holes (in fact, ll of them) in the gMax bed's steel chassis.