I am balancing the drum of my Delta Drum Sander (woodworking). I got it used, and I don't know who balanced it, but it was shaking a bit.
I haven't gotten it all out yet. But using my cell phone in slo mo, and VLC I can watch frame by frame so I can see my reference mark on the shaft, and the dial indicator to see where it is out of balance. It's a game of vectors, since the vibration is slightly out of phase with the balance. I would have thought it close, but I'm learning.