Duo Britannic
So this machine is the rarest of the rare - one of the elusive twin Britannics that were built at the beginning of World War 2, in an attempt to replace the German Brunsviga double calculators that could no longer be imported, but were necessary for artillery calculations. Unfortunately, Britannic didn't get it entirely right according to the British army, and instead Block and Anderson was contacted in 1942 to pair up American Marchant machines into double calculators. Alan Turing had one of these, and it is currently at the Manchester Museum of Science and Industry.
Image courtesy of the seller, Salvaged Ltd.
So when people started emailing me that this machine had appeared on ebay, I couldn't believe my luck - it was the last brand of double calculator missing from my collection. Clearly, it was blocked, because the handle was pointing up at an awkward angle, but this is usually quite easy to remedy. So I bought it, and at a very reaonable price at that.
When it arrived, a week later, very carefully wrapped, I unpacked it, and noticed that it was not "just" blocked, it was completely frozen solid - there wasn't even a tenth of a millimeter of movement anywhere - not in the crank, not in the clearing butterflies, not in the carriage, nowhere. It was as though the machine had been cast as a single piece.
Taking the top off, it was immediately clear why this was - the machine had suffered from water ingress, and was completely, totally, utterly rusted solid. It looked like something that had been sitting on the main deck of Titanic since 1912.
So obviously, the restoration took some time ... I estimate about 120 hours. You can follow the entire process, with pictures, here. (warning: very picture-heavy!)
This is the final result:
