This is my take on a No-Hob Extruder. This was loosely derived from profezzorn's extruder: http://www.thingiverse.com/thing:28430
however I only used the concept of using a bit, rather than a hobbed bolt. I basically redesigned each piece to make it more compact allowing a small bit more Y axis clearance. I also provided a lead-in chamfer for the filament on the main extruder body to keep from binding. The mounting pattern is designed with a Budashnozzle in mind. This is designed for 1.75 filament.
Source files are SolidWorks files. I have included those, along with a STEP file of the full Assembly. STL files of the printed pieces are also included. I will update this a bit later with the full functionality explanation, BOM, and instructions.
I tried to keep all hardware SAE except for the three screws for the Nema17. The hobbed bolt is replaced with a #115 Dremel bit that can be bought for ~$5 at WalMart. All bearings are standard R2 bearings, that way you don't have two different sizes. And it uses a floating barrel nut to tighten the hinge. This can be bought for cheap at Lowes in their hardware section in a furniture accessory drawer.
Qty:1) 1/4-20 SHCS 5/8" length
Qty:1) 1/4-20 x 3/8" dia x 5/8" length barrel nut (Hillman Group item#137362; purchase at Lowes ~$1.15)
Qty:1) 10-24 FHCS 1-1/8" length
Qty:1) 10-24 Nylon inserted lock nut
Qty:1) #115 Dremel bit (Walmart ~$5)
Qty:3) R2 bearings (1/8"ID x 3/8"OD x 5/32"W)
Qty:1) 1/8" dowel pin x 3/4" long
Qty:3) 8-32 set screws 5/16" long
Qty:3) 8-32 machine screw hex nuts