Direct Drive Bowden Extruder for 20 mm extrusion

Direct Drive Bowden Extruder that latches on (bolt free) to 20mm extrusion. Can also be fixed in place with a single bolt. Features:
-simple, open, & compact
-easy to clean and adjust
-designed to be drilled out for 1.75 or 3mm filament
-designed to be drilled out for a 5mm or 1/8 coupling
-will work with the shown Arcol hobbed pulley or a mk7
-pulley is positioned close to motor base to reduce cantilevered load on motor shaft
Inspired by every other open source extruder out there.
Note: I am using an 86oz*in motor with a DRV8825 stepper driver on 1.75mm filament. You may want to use a geared stepper driver for 3mm filament. They can be found on ebay. Just make sure they can still mount on the normal Nema 17 bolt pattern.