What is best non geared stepper extruder design now ?

What is best non geared stepper extruder design now ? I mean system like mk7 with no gearbox or printed gear. Just direct drive like minimilstic mk7 extruder. @Whosa_whatsis you didnt use your mk7 with bukobot reason ?

The Bukobot doesn’t use my mechanism because it’s designed for 3mm filament, the 3mm extruder parts were manufactured and geared steppers purchased before I came onboard, and my design isn’t good for 3mm.

If you’re going for direct drive, you should use 1.75mm filament.

Personally, I prefer a 1.75 direct-drive setup.

Is adaptation to tiny changes in filament diameter as much of an issue with 1.75mm as it is with 3mm? If so I recommend a spring loaded design.

This is the one I changed to make it stronger. Works like a charm but is for 3mm.

Well, a .1mm change in diameter has about 3x the effect on the volume of 1.75mm filament that it does on 3mm, so diametric consistency is more important. OTOH, 1.75mm filament is more likely to have been originally extruded with 3d printing in mind, as opposed to plastic welding, for which volumetric consistency is not a concern and lumps or bubbles are not uncommon. Most suppliers state diameter tolerance in % of total diameter, and a 5% variance in diameter turns out to make a bigger difference in volume over the same expected volume by about 2%.

Edit, disregard that last sentence, I just woke up, and made a stupid mistake in the math that introduced that 2% error.