Speaking of other lock washer options, have you ever seen a Nord-lock, a serrated flange nut, a castle nut, or a slotted nut? He also mentions chemical lockers and nylock nuts, which we have used ...

You no longer find many traditional fasteners like lock washers ... However, over-tightening with a hand or power nut driver can be a problem. Flange nuts and bolts have a built-in flat washer ...