Ground loops are a big problem when grounding. When it's done properly, you will eliminate ground loops. The idea is to make sure that you are not relying on a connection between two parts, that are painted, to be grounded. They are NOT. Only bare metal to bare metal will provide the necessary grounding that prevents those loops.

We had instances aboard Coast Guard ships where there was constant rattling sounds coming across HF receivers. We traced it down to places on the ship where there was an opening in the ships railing that were closed using chains. These chains rattled as the ship rolled and pitched causing the noise over the radios. We ran a ground wire from one stanchion to the next basically providing a ground that eliminated the rattle chains. Another area was where metal ladders connected to the decks. Again, rattling of the ladders caused noise in the HF radios. We put a ground wire between the ladder and the deck, bypassing the rattling pin and eliminated the noise. In my amateur radio setups, I put in grounding systems that were fairly complex. As grounds are part of an antenna system, my antennas performed much better because of proper grounding.

Since applying the grounding methods I learned from 23 years in military electronics and another 11 years as an amateur radio operator, my ShopBot has run pretty well. Still get occasional brain farts from the ShopBot. That just stems from archaic connection technology between PC and controller.