This is an extruder for a rebuild of an early Prusa Mendel with a 5:1 gear ratio and a NEMA14 stepper motor. The design intent was to reduce the weight of the X carriage without resorting to a Bowden type extruder and to make loading of filament easier than it is in most existing designs.
This extruder has been tested at 60mm/sec with ABS, PLA and Ninjaflex.
The printed parts were printed in ABS with 3 vertical shells and 3 top and bottom layers, 20% infill. Additional information is in the PDF document. As the mounting was intended to be directly onto a 2mm aluminium plate STEP files have been provided so that you modify the design to meet your needs.