Here are some photos of my Extruder 'cold-end'. The motor wasn't yet secured in this shot but is now bolted to the base.
The cogs are salvaged from an old photocopier. I realise the smaller cog has typically less teeth in other designs but we'll see how this one goes! The stepper motor is from an old 5.25" floppy drive!
The bearing recesses were achieved by clamping the two 15mm blocks together and drilling a hole 22mm diameter with a flat wood bit to a dept equal to the bearing width, so the bearing would recess until flush with the edge. These recesses hold the bearing snugly in either side of the block.
Here you can see the bearing mounting block for the filament drive shaft, and it's partner, the idle pressure bearing (smaller bearing pinned into the second block.)
Here's a photo of my extruder filament drive mechanism components.Everything has been done with minimal power tools, a variety of drill bit sizes, some files, tap and die set, saws and a bench vice. I have some photos of the 'hot-end' which I'll post next.
Thanks for viewing. Comments and questions welcome.?