Back then, they did not have B18.22.1, The name was whatever the drafter wanted to call it. In my manual, pages right opposite each other have the same washer called plain and flat with two different drafters. They don't list the part no. Most of the vendors who sell B18.22.1 call it a flat washer on their websites. Some people give the diameter as how "wide" a circle is. If that's OK, then plain is OK. Just going by what I was taught many years ago by Elmer Sperry's Company, the person who coined the word "Automotive" in "Society of Automotive Engineers", as an early SAE member. Nice, but all trivia. To me "Wide" is incorrect and "Plain" is incorrect. Like "Original" is to others
