Ender 3 Pro Y axis - MGN12 Linear Rail

thingiverse

This is a conversion for MGN12 3 point bed leveling on the Ender 3 Pro and it will also work with the OG Ender 3 and possibly other printers that use a single 2040 or 4040 extrusion for the Y axis. Files are included in iges, step, fusion, and STL formats so you can edit or machine your own version of this conversion. This design can be used as a template to drill the necessary holes by hand. All bed mounting holes match the stock Ender 3 spacing. My goal was to keep the original look and parts of the printer while running the belt path as close to center as possible. Since the Ender 3 Pro uses 4040, the MGN12 is offset to run on the right side of the extrusion with the belt running on the left side. The front nylon spacers around the front tension will need modification. You can either cut one down to 5mm and place the remaining piece on the opposite side of the idler or get 25mm and 5mm M4 spacers. The Y axis motor mount needs to be moved left as viewed from the front, and 1 hole on the extrusion may need tapped for M5 to attach the 2 bolts. The 3rd bolt can be attached to the extrusion using a 90* corner bracket, 1 M5 T-nut, and an M5 SHCS. My next step is to have this machined in aluminum and take remaining install pictures. Update: I modified the slot for the belt; the original version had the slot backwards.