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Robo 3D R1+Plus 60mm Hobbed Bolt Fitting with Wiring Arm

Robo 3D R1+Plus 60mm Hobbed Bolt Fitting with Wiring Arm

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by crorsina February 11, 2018

I needed to replace my extruder's stock M8x50mm hobbed bolt. That size does not seem to be widely available, but I found a few 60mm ones. I also recently had to remove the zip ties from the extruder's wiring, so I wanted a way to better secure all that. The combination of those issues resulted in this design.

The bearing and washer are taken from the gear side of the existing hobbed bolt and reused. With the wiring zip tie removed, I can't see any purpose in continuing to use a bearing as a spacer on that side, so it is replaced by a printed part. The washer provides a metal contact surface between the printed spacer and the bearing housed in the extruder body. For the part on the wiring side, the bearing is inserted mid-print so that it is encased in the part. I added two more washers between the bearings on that side to give it a really solid feel when tightening up the bolt, though you could probably get by with one or even zero. It's a bit tricky getting washers in there and there's just enough contact surface on the part that the washer(s) could be unnecessary.

Anyway, seems to work just fine, my prints are looking better than ever with a new hobbed bolt in there, and I didn't have to overspend or wait for international shipping. I'm happy with it and I hope you are too.

Print Settings

Printer brand: Robo 3D

Printer: R1 ABS + PLA Model

Rafts: No

Supports: No

Resolution: 0.2

Infill: 33%


On the piece for the wiring side, pause the print at layer 42 to drop in the bearing. I didn't have great luck getting the next layer to adhere to the bearing, but I only made the one attempt since it did eventually build up enough material to hold. I think a bit of glue stick around the edge of the bearing's upper surface might have done OK. That or maybe check into how people go about printing fidget spinners.

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