Regarding filament drive:
*For 1.75mm filament you need 604s or smaller.
*Counter rotating could be done with bevel gears.
*You could use the edge of the bearing instead of the flat to increase the grip and remove almost all of the sliding friction.
I really like this idea. I think I can do it with 6 604s and 3 608s and some random bolts. It has enough potential to warrant a mock up and a possible test. I will put it in the developer forum when I get the time.
*For 1.75mm filament you need 604s or smaller.
*Counter rotating could be done with bevel gears.
*You could use the edge of the bearing instead of the flat to increase the grip and remove almost all of the sliding friction.
I really like this idea. I think I can do it with 6 604s and 3 608s and some random bolts. It has enough potential to warrant a mock up and a possible test. I will put it in the developer forum when I get the time.