Instructions
1. Make your stepper motor shaft rough (e.g. with a dremel cutting disk).
2. Put an M4x16 bolt into the 624 bearing. Put a washer between it and insert it into the printed part as seen in the picture. Put another washer on the other side and fasten it with an M4 nut.
3. Bolt the extruder onto the printed part, with four M5 cap screws, use washers.
4. When using ABS you can tighten it so that the washers will sink into the plastic creating a very tight friction fit. It is soft enough that it won't crack. With PLA you should be more careful.
You can stack several of them with the mounting slots on the sides. This is useful for multi-material RepRaps. The design is future proof :)




