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Two Bit MK8 Extruder

Spring held extruder for bowden use. Mounted directly onto NEMA17 stepper motor. Using Mk8 gear for strong push. Low parts count - only 3 printed parts, 4 screws, Mk8 gear and pneumatic adapter.

3D printer parts and enhancements

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Print the STL file. You will get "upper feed", "upper tensioner", "lower tensioner".

1. Clean up the two holes that the filament pass through with a 2mm drill bit (one in each part)
2. Clean up the the three vertical holes in the upper parts with a 3mm drill bit
3. Clean up the two vertical holes in the lower part with a 2.5mm drill bit, and tap with a M3 tap
4. Clean up the hole for the bowden tube with a 4mm drill bit, and tap with a M5 tap. You might want to drill the hole a bit deeper than printed, unless you have a bottom tap. Screw in the pneumatic adapter.
5. Put the bearing on the lower part, and assemble with upper part with the 12mm M3 screw.
6. Screw the assembled tensioner part onto the motor with a 16mm screw. Do not over tighten.
7. Mount the Mk8 gear onto the motor - align with the height of where the filament passes through.
8. Screw the feed part onto the motor with one 16mm screw.
9. Insert the spring.
10. Hold the two parts together, compressing the spring, and screw in the last 16mm screw.

All done!

Suggestions for mounts are welcome - I've just thrown them on top of my large printer at the moment.

Materials and methods

- 3 x M3 16mm
- 1 x M3 12mm (or 10mm will do)
- 1 x pneumatic 4mm to M5 adapter
- 1 x 608ZZ bearing (skate bearing)
- 1 x 25-30mm strong spring with 10-12mm diameter
- 8m 1.75mm PLA/ABS filament



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90566e9e936e49ca401b69e29345d5e4?default=blank&size=40Mauricio Fenoglio added this to the 3D Printer collection ago
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Mini captureLars Karlslund published this design ago