All drum brakes have this issue. All of them. Add some years and some rust and..well you get the picture. Just a word of advise, from the school of hard knocks, don't turn the drums. You can remove the "lip" but don't turn the drum. Clean and check for round, use a bit of anti seize on moving parts when reassembling to prevent this kind of hassle later. You can blast the rust off the outside of the drum and paint it with some Hi-Temp satin black, Looks good, just don't use a heavy coat, it will not help with the heat dissipation. Adjust often and clean sometimes. It is kind of a Zen thing but helps with peace of mind.
