My main interest is toy steam engines, I have 30 odd dating form early 1900's to new and during the collection/repair process it's inevitable that one accumulates an assortment of surplus bits & pieces, sometimes there's almost enough parts to make another toy... I got the Mamod MM1 boiler from EBay pretty cheaply last year without any real intent, it was just too good to miss. Recently blew the dust off it and set to - I found a suitable piston/cylinder assembly in one of my spares boxes, the crank is 1930's Doll, the flywheel was originally supporting a brass cannon ornament found in a charity shop (again, too good to miss!) and the chimney embellisher is the top of a brass candlestick, no prizes for guessing where that was bought. Some spare brass sheet for the firebox and a copper pipe end stop for the burner. She runs very sweetly - video here of the first successful steam run, I confess to making a podge of the steam pipe soldering which needed a teeny fix first:
One minor issue, now sorted, she needed a chimney drain to lose the condensed exhaust steam, easy addition.