Thanks Mcdougal. Since we know one of yours is post-1954 (the one with the wooden handles and pepperpot exhaust), obviously the no-keyways situation went on for quite a while. Incidentally I bought my 12" pretty cheaply because the previous tenant had pulled the flywheel, fitted a new moving breaker arm bent at an acute angle to the fixed point so the points couldn't even open, and thrown away the porthole cover for the flywheel. (The flywheel itself was supplied as a loose part.) The buyers weren't exactly lined up and bidding against each other to take on that challenge. It took me something like 2 hours to work out what the breaker gap had to be to ensure the moving magnet was in about the right place, bend the breaker arm so the points met each other square-on, time it to slightly before TDC, and make a porthole cover out of aluminium sheet. I was cursing my purchase decision pretty freely by then.
