2/1018 I have since made a switch to the cr10 extruder to test it out on a variety of extruders and I have to say that it is working GREAT!! I can't wait to try flexibles with it, also just setup a cyclops with it and going to be testing that out very soon..
2/6/18 It has came to my attention that a flat area will need to be grinned into the round shaft as I have been seeing slipping of the extruder gear. A simple metal file or a dremal tool should be fine to use.
2/2/18 Ok it's confirmed that this works! (My printer is printing with it right now)... Do note: My extruder steps_per_mm needed to be changed by almost 4x my original amount. Nonetheless, this extruder setup seems to be very accurate.
2/1/18 I have actually ended up using my original aluminum MK8 extruder mounted to the frame for this instead of a printed extruder as it functioned better and is easy to attach. Why replace something if it worked fine before? This will make for less printing and hopefully people could use this system by simply attaching their current extruder. Also, I noticed a little bit of slipping so i made a small washer to increase the spring tension some. So far it works. I'm about to start a long print to try it out.
As I use the design more I can refine it and make improvements.
NOTE: It's best to get a shaft that is 5mmx50mm for the large gear.
1 5mmx50mm Shaft https://www.amazon.com/gp/product/B01MTKNWZB/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
1 60 Tooth Gear 5mm hole https://www.amazon.com/gp/product/B074V7HVHB/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
1 16 Tooth Gear https://www.amazon.com/gp/product/B06XH3BZBC/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
1 Drive Gear
3 3mmx25mm Screws
5 3mmx12mm Screws for motor and mount
4 3mm Nuts
1 Nema 17-Mounting Extruder of your choice.
2 4mm wide x 5mm ID x 13mm OD bearings
1 200-2gt belt
When printing these parts I used 50% infill, but you could probably get away with 20%. I printed my version at 0.4mm layers heights using a 0.6mm nozzle. I'll probably re-print everything later on using 0.2 layer heights. Good luck and let me know if you have any questions.
The area on the bottom where the bearing inserts might need support, depending on your printer. If so, a 1/2" drill bit in the size works great to clean it up and make it flush. To clean the M5 screw holes I found a 13/64" drill bit works great, and a 1/8" drill bit works well to open up the M3 holes.
A 0.4mm nozzle at 0.2mm layer heights would prove more accurate then my 0.6mm nozzle at 0.4mm layer heights. Enjoy.