Summary

This is a filament drive for a bowden type extruder.
Based on the very successful Air tripper design. I wanted to make a few changes to increase the strength of that design and have ports for 1/8" BSPT fittings. It is also suitable for 3mm filament.

Instructions

BOM:
5ea M3x25 screws, pan head or socket head will work.
1ea M3 Nut
2ea M4x60 screws
2ea M4 Nut
M8x20 grub screw or anything 8mm diameter and 20mm long
608ZZ bearing
625ZZ bearing
8mm hobbed drive pulley
NEMA17 stepper motor
2ea springs for tensioning about 25x6mm 0.8mm wire dia.
2ea M4 washers
M4 bolts for mounting extruder
4mm pneumatic quick connect fitting 1/8" BSPT of NPT if using 1.75mm filament.

The drive can be used for feeding in either direction. Just choose which side to fit the pneumatic fitting to.

After printing there is a section of support material to be removed from the body.
Drill the filament tube out to 3.5 or 4mm if you are using 3mm filament. As long as you use 3 or 4 perimeter passes.

Versatile filament drive