Awww, Wills, thanks for looking out for me and my balls, but I need 12mm precisely, I looked at McMasterCar and they only sell standard sizes. I am pro Silicon Nitride though. Only problem is the ones I found are here.
They won't let me order just 6 though. Got to order $50 worth. Anybody have a source for ceramic balls? Gotta be 12mm right on the dot.