I have been printing wheels for a kitchen draw, 20mm dia, 6 mm thick and with a radius (like a bike tyre) not a flat surface, and little stub axles of 3 or 4 mm. The start and end of the wheel (printed vertically on a raft) are a little rough, nothing serious as it will never be seen but the one change that would seem to make a difference is a finer thread of plastic. As I only want to change the nozzle my initial thought would be that this was easy, but it's full of solid plastic and needs to be tightened quite specifically (or heat it and have plastic running everywhere) and with a gap so it does not hit the Al block or damage the heat break. Do I need to take the whole assembly out, heater etc. and remove the whole thing from the X-Carriage or is there a simpler way?