I know there have been a lot of discussions of grounding practices, but I haven’t found a definitive answer to this one:

I recently added a VFD and spindle to my K2CNC, and I think I’m having occasional electrical noise issues. I grounded the spindle housing back to the VFD earth, and my machine frame is also grounded to earth at its control box. Does this cause an undesirable ground loop, or should I not worry about it? It seems that using only one of these ground connections would then rely on current flowing through the bearings on the axes.

While I’m at it, what are the current thoughts on whether to connect only one end or both ends of the spindle cable shield to ground?