dndrich One of two things will have happened, if you couldn’t hear metallic screeching….
The calibration setting wasn’t quite at burr touching, or the burrs were jammed and not moving….neither should have done any damage to the grinder…burr jamming is designed to not cause damage….as the grinder will simply cut out on it’s one.
Just want to make the point (again) about calibration….as this post has reminded me by mentioning the word only.
The Niche only requires calibrating, if you have accidentally moved the black grind indicator ring (the clicky one). If you haven’t moved it the Niche never needs calibrating after the first month or so once the burrs have run in a bit. When you clean the grinder and put everything back….it always ends up back in the same position and does not need recalibration.
The screw thread only has one entry point…so it will always assemble back to the right place. It is worth marking the top burr carrier and always ensures it goes in the same way.