I was up in Monroe today -- a small town about 25 miles northeast of Seattle -- and went to their Coast to Coast Hardware store, which I knew had a Forney display. I was following up on a thread here from a few weeks back. Sure 'nuff, they had adapters to go from M10 to 5/8-11. I have two Makita 4" angle grinders. Thing is, they sell *two* adapters: M10x1.25 and M10x1.50 and I wasn't at all sure which one fits a Makita. I guessed it was the fine thread and sure enough it spun right on when I got home. About six bucks, and whoever said they'd only have one was dead on, else I'd have bought two.
The Forney part number is 70550, and it for sure adapts Makita 4" angle grinder spindles to 5/8-11.
Grant Erwin Kirkland, Washington