Just realized my cone wrench slipped on a hub cone at the co op in Portland and I had been holding it wrong
I was at the bike co op over on Mississippi Ave helping a guy repack his rear hub when my cone wrench kept slipping off the flats. An older mechanic named Ray walked over, looked at my hand, and flipped the wrench so the flat side faced the cone instead of the angled side. He said the angled side is only for getting into tight spots, and using it full time rounds off the cone corners. I had been doing it that way for 3 seasons, and sure enough two of my own hubs have chewed up cones sitting in a parts bin. Has anyone else had a co op regular drop a tip that made you rethink something basic?