I've seen lots of threads where folks have cut or stamped out small discs to represent the instruments on aircraft instrument panels. I wonder how many of these they've thrown away:
I always save bits like these dave, ive got a big spares box full of allsorts of random bits , but one day they might come in useful! As you say they would be perfect for instrument backs in 1/32 or 1/48 or anywhere you need a cylindrical piece. Cheers tony