That one advantage of having a working shop. I usually buy things like nuts in bulk. Just be aware to there several version of these flange nuts. You want to go with the serrated version as that is considered a locking type. If you wrench or socket clearance issues you might want to go with the JIS version. It is the one I need here on Kawasaki engine's exhausts as a 13mm socket just won't fit but the JIS is 12mm socket size so it fit fine.
