I finally put the thing together and 30 minutes later, was running it and giving the dogs treats. So far, Koji doesn't seem bothered by the sound at all. But that will be different when I have him on his back and that thing near his nails. He hates that. So, more treats.

Vogue comes for treats but stares at it like it's going to kill her any moment, but food is very important, so eat treats first while watching it like a hawk. LMAO!
Oh, I attached the flex shaft for easier handling (for me) and for less sound (I can move the main unit away from the dogs). For now, all I have is the 1/2" bit, so we're going to go for it. I tried it on my nails, not bad. BF said, "oh look, a buffer. You can buff their nails afterwards". Haha.
I'm excited. So, today was day 1. I may try Koji's nails tomorrow, as in putting him in position, bully stick in his mouth, and see how he does with the sound. I think I'll just touch it (not while it's running) to his nails, so he gets what I'm doing.
Vogue, I think will take longer..or just put up with it. We'll see. Not sure if she'd like a bully stick in her mouth too. Haha.
I'm super excited.