"The other method takes more time, but does the same job! With the brake shoes on the car, put masking tape around the diameter of both brake shoes. Now slip the drum in place and put the axel nut on. Spin the drum. Now remove the drum and examine the tape. The tape will be worn off where you have high spots on the lining. Grind down the high spots until you can assemble the drum and not have any drag from the lining. You may end up putting the drum on and off several times, but that is the only way of do-ing the job."
https://www.oneillvintageford.co.uk/acatalog/A-1126.pdf