This is a compact bevel geared extruder that is designed for the small pneumatic fittings available at e3d.
The gear ratio is 2.3:1 which gives more than enough torque even with a smaller NEMA 17's.
It's easy to assemble the only thing I would say is the shaft on the stepper motor needs to be cut down by about 10mm.
2x 605 zz bearings
1x mk8 hobbed filament gear
1x M5x45 hex socket screw
1x M5 washer
2 x M3 grub screws
3 x M3 nuts
4x M3 Washers
2x M3 x35mm hex socket screw
1x M3 x45mm hex socket screw
1x M3 x 30mm hex socket screw
2x tensioner springs
1x 608zz bearing
18 July 2014
The main extruder body has been updated, It has a bigger input hole for PTFE tubing and a groove around the drive gear to stop softer materials like ninjaflex from jamming.
27 April 2015
The design has had a complete overhaul, The main extruder body size has been reduced as this no longer uses screws to tighten the Idler, it also makes it easier to remove the support material. The idler has been changed to only use spring tension which makes it easier and quicker to change filaments over. The gears are still the same.
I've been using this since February and haven't any problems.
I'm probably going to work on a design to be able to mount the idler arm on either side depending on the orientation of the extruder next.
13th July 2015
I increased the size of the idler pivot which makes the idler straighter I also made the idler smaller to increase the tension. You only need one spring for tension now.
Print it and put it together. 30% infill worked well for me and 0.2mm layers work best so you can easily snap the supports.
In the firmware I set the number of steps per unit to 356.5