I just have the 0.6mm nozzles mine came with. I recall hearing something like that, but I’ve felt that the phat 0.6 lads were good enough for the stuff I’m printing. If that’s a limitation, then I hope Prusa can fix it. Seems like it shouldn’t be a big deal to make that configurable.
Man, that’s cool! Concrete is a heck of a lot cheaper than epoxy granite resin and is perfectly suitable for a low-precision tool like this lathe.
I do hope that he finds a way to shield those bearings. You really don’t want metal chips or sawdust making its way in there. Any damage they sustain will cause runout, which will lead to increased chatter and parts that are out of spec. Plus, a matching pair of tapered roller bearings can be quite expensive!
EDIT: to be clear, I mean no disrespect when I say low-precision. Not every lathe needs to have slides and handwheels. I have a little Sherline lathe that I’ve used like this in the past (using gravers, not tools in a tool holder). It’s great to quickly turn something or to put nice decorative details on a part. Precision is possible with a lathe like this, but it requires fairly strenuous effort.