I think this may be related to the other posts here like this one.
I had to abort the last carving attempt, when my stock broke free and the ball-mill was crushing through the fragile details. I think I may have hit the power switch rather than the emergency stop button.
In any case, when I run now, on homing the X-axis motion makes an evil noise. When powered down, it moves smoothly when pushed by hand. I removed the back of the case to see if something physically had fallen into the works, but see nothing unusual. I also looked from broken wires to the stepper motor, but they’re all fine when visually inspected.