I like GW extruder and saw some ways to improve it. Indeed all my current Piper printers (https://www.thingiverse.com/thing:2794632) are running on this version or AJGW extruders.
Problems I tried to fix are: E3D hotend is mounted on 2 screws and moves after some use; closing filament clamp (compressor... name it) may jam filament. Have added a new fast release, which works better for me opens and closes easier. Included mounts for Bowden tube and for E3D hotend.
Autocad Fusion 360 project may be found at: https://a360.co/2Iu8v5x or downloaded as part of all files. Autocad assembly contains components from McMaster webpage, E3D from https://www.thingiverse.com/thing:341689 , and I do not remember the source of NEMA 17 component.
Quick release in action: https://youtu.be/Ad7Fl6Ia978
As noted by Alain idler mount, which I call "filament compressor" may need to be printed on a side.
You may also check my website https://piper3dprinter.com for other things I do.
You will also need:
3 - 608 ball bearings
1 - 18mm pin (may be a rod cut from a bolt) 5/16 or M8 to mount ball bearing in the "compressor" (idler)
2 - M4 50mm not fully threaded bolts for quick release
2 -1/4 in x0.5 in x0.035 in (6.4 mm x12 mm x0.9mm) (maybe other which will slide on M4 and held by M4 head) compression springs
1 - Nema 17 motor
1 - Hobbed bolt 5/16 or M8 (check my things for a tool to make one)
2 - nuts 5/16 or M8 to lock hobbed bolt
3 - M3 8mm bolts to hold the motor
1 - #6 1.5 in or M4 30 mm bolt and nut to hold idler ("compressor")
2 - #4 3/4 in or M3 18-20mm screws and nuts for E3D or Bowden mount.