My hemera+volcano was printing great for about a year. About a month ago I changed the nozzle from 0.4 to 0.6 and it continued to print great for about a month. Until mid-print filament wouldn't extrude or retract. I couldn't hot/cold pull my filament out. I had to yank my filament out until it snapped somewhere inside the gearbox. So I disassembled my Hemera for the first time, cleaned out a bunch of flakes which I assume were pieces of filament (but now I'm now I'm suspicious it was metal), and reassembled. I got through about half a layer before the same thing happened. I disassembled a 2nd time, same thing. Now I'm on the 3rd and looking for help. E3D's documentation (link) says to screw the HotSide into the Hemera Main assembly "finger tight". Here's a video showing what happens when I do that: The gears spin fairly well when the heatbreak is loose. Twisting it until it's "finger tight" though and you can clearly hear them scraping against the heatbreak. The gears also sound like they're grinding when the heatbreak is removed and the tension knob is too tight. I would expect the gears to be harder to turn, but they really sound like they're scraping against something inside the assembly. So... how did I mess this up? Things were great until I had to disassemble this thing. Now I'm wondering if it can even be reassembled properly. It feels like the tolerances on this thing are too tight for anyone but an E3D technician to properly put it together.