Seems like I learn something every time I turn wood. Over the weekend I made a simple cylindrical plinth to stand a trophy on, couple of beads at the top, and a bead and half-cove at the base.
I started with a tenon at the base, finished the top, then reversed the piece holding it in the 8" jumbo plates (Cole Jaws) so I could finish turn and sand the bottom.
It was running true, so I increased the speed to maximum, hoping this would give a nice smooth finish if I took really light cuts. After removing the tenon and making a couple of smoothing passes, I switched off the lathe to check how it was looking ...
WHAT I LEARNED: my lathe's motor and drive shaft stop turning pretty fast -- faster than the inertia of the chuck and jaw plates liked. The whole thing unscrewed from the drive shaft, fortunately friction slowed it down and it dropped gently onto the lathe bed.
At least it didn't fly across the room, and I was able to fix the workpiece by trimming it down to just a couple of beads at that end.
From here on, when I want to stop the lathe I'll drop the speed to its slowest setting before hitting the power switch.