A GOOD auto parts store will have a Dorman section. Orange and Black steel cabinets with every fitting,washer,brass or steel plug,ferrule,etc....etc.... under the sun.
Back 45 years ago, i didnt even know what a "wave washer" was til i started looking thru the Dorman display. I spent probably an hour there that day.
So.....find a Dorman display and youll find your 1 1/4" copper washer.
The worst part is getting the rummy behind the counter to figure out how to price it.
Good Luck,
