Entruder

Extruder for Ender 2, 3 and similar printers.

This direct drive extruder shares many features with Orbiter, HextrudORT, Sherpa Mini, MicroDrive and similar extruders.

Gears is from a DotBit extruder and it uses an Nema 17 pancake stepper motor.
Bondtech “main Shaft Assembly” works as well but I haven’t tested Bondtech motor and lever gears.
https://www.bondtech.se/product/shaft-assembly/

It attaches directly to the heatsink with no compression fittings in-between.

Printed compressor fitting on feed tube.

Max flow rate with stepper motor 17HS01-1004S (1A motor capped to 535mA) is ~14mm3/s
Retraction 0.2mm

Biting deep is designed to be 0.2mm (as recommended from Orbiter 2.0 project).

I use a cheap bi-metal throat that I polished. Works really well for PLA, PETG and ABS.

Print bed adhesion was a little problematic so supports and brims is included in the models.

Screws:
4 M3x20 screws
3 M3 inserts

Compatible with “HUSH! Quiet cooler for Ender 2 / 3” https://www.thingiverse.com/thing:4642521

I also recommend BMG Knob Knob https://www.thingiverse.com/thing:6727842
Fusion 360 files included.