This is a geared extruder for Rostock and other printers, it uses 1.75mm filament and 4mm Pneumatic fittings for PTFE tubes as the Bowden element.
Print out and assemble with Herringbone gears (any to fit Greg's design) and use the 1.75mm filament guide here.
Flip the design if you want it mounted the other way around or if you are planning a dual bowden extruder setup.
I have been running it for about 4 months, works really well - and can mount to t-slot frames if you like.
Sketchup file added so remix it if you like.
BOM as requested -
It's very similar to any of the other Greg's / Wade's Extruders on Thingiverse -
To print the 1.75mm Version -
So you need to print the two models here.
And a set of Gears - I recomend using the Parametric Herringbone Gear Set for Greg's Accessible Wades - by Triffid Hunter - thing:10707
The hobbed bolt is a standard 8MM type, it should be the most common available from many places - check eBay.
Some long M3 screws for the pressure block springs (about 55mm long)
1 x 35/40mm M3 screw for the pressure block.
Two springs or silicone pads.
3/8" or 10mm Pneumatic fitting to accept 4MM PTFE Tube.
A length of PTFE tube 4mm OD 2mm ID
4 x M3 x 10mm bolts for the motors and small gear
M3 nuts x 5
M8 washers - to space the hobbed bolt correctly
I think that's it?
Or use the Version by Woodsmoke if you use 3mm Filament.