Ender 3 Neo BMG Direct Drive Mount

I designed this direct-drive BMG mount for the Ender 3 Neo due to limited options. It may also be compatible with other Neo series printers.

Files
There are two version. One has 8-mm diameter holes for the POM wheel spacer. (E3Neo BMG DD 8.stl) The other has 7.8-mm (E3Neo BMG DD 7_8.stl). Choose the one that is appropriate for your printer tolerance. It is better if the spacers are in the holes tightly to prevent the mount from wobbling. If the 7.8-mm model is still too loose, just use tape to make the fit tighter.

Print settings

• I suggest printing at the default orientation of the model (supports required)
• Material: I printed it in ABS but PLA and PETG should work
• Layer height: 0.2 mm
• Walls: 5
• Top/Bottom: 5
• Infill: at least 50%

Installation

1. Remove the hotend cover, hotend, and fans from the x-axis carriage.
2. Loosen the x-axis belt.
3. Loosen the nuts on the two v-slot wheels resting on the top of the gantry until you can remove the carriage from the gantry.
4. Remove the belts from the carriage.
5. Completely remove the nuts on the two upper v-slot wheels.
6. Remove the spacers and transfer them to the 3D-printed BMG mount's designated holes, ensuring a tight, wobble-free fit. If loose (even with the 7.8mm model), you can use tape around the spacers to make them fit tighter. Spacers must be flush with the carriage side of the mount.
7. Reassemble the x-axis carriage and reinstall it to the gantry.
8. Reinstall the hotend onto the carriage and insert a short PTFE tube into the coupler. The PTFE tube should be 32.7mm + how long the tube should be inside the coupler and hotend. I have a bi-metal heatbreak installed, and I used a 71-mm long PTFE tube. I think it should be around the same length as the stock heatbreak, but it's best that you verify.
9. Install the BMG extruder and motor to the mount while making sure that the PTFE tube is inserted into the BMG extruder outlet. If you have enough space, you can orient the motor with the cable facing downward. Note: Don't use a coupler on the BMG extruder outlet