Lyman Filament Extruder
See other FB posts on build prep - 
Your work appears to be very interesting.
I don't visualize my being involved in your workshop as I am now 87 years old living in Enumclaw, Washington.
My latest Filament Extruder, Version 6 is the only extruder I am now supporting. It is my favorite extruder and all my filament is now produced with the three I have made. It extrudes 3mm (2.65mm) filament at about 1/2 lb/hour with the gear motor running at 25 rpm. The motor is rated for 33 rpm but under load it only goes about 25. . A faster gear motor with about 100 kg-cm of torque may give 1 lb/hr. I get a filament that varies not more than .05mm with the extruder wall mounted.
This extruder is posted on Thingiverse and is open source CC share alike. The posting includes a BOM. Also there is a video on YouTube.
- Uses 173 kg-cm torque motor (150 lb in) , but a 10 lb-in stepper (2 nema 17, 80 oz-in motors) reduced 10x may be sufficient (so still can use small, cheap steppers, no more than $20 in stepper motor costs. Advantage is that we are introducing no new parts to the GVCS, as steppers are already used.
- Lyman Filament Winder
- Lyman Filament Extruder Part Library
- Thingiverse - v6 - http://www.thingiverse.com/thing:1199870. Download BOM + files (backup in case if Thingiverse goes south) - File:Lymanv6.zip
- Comments on Thingiverse provide some useful details.
- Spool winder v3, Jan 2016 - . Download - File:Lymanspoolerv3.zip
- Plastic Pellets.