Cypher machines maintenance and restoration spanning sixty years

Cryptologia, Jul 2003 by Clarkson, Dorothy

In the autumn of 1952, after a prolonged illness, I was invalided from the RAF and a year later joined a company manufacturing flight simulators and trainers, later to become Rediffusion Simulation Limited. Thirty-three happy years later I finally retired, having reached the exalted position of Senior Systems Design Engineer.

BLETCHLEY PARK

In 1999, in the TV programme 'Station X', I saw for the first time an 'Enigma' machine, which I had not previously even heard of and was astonished by the similarity of its encoding mechanism to that of the Typex that I had known so many years before. To see this in the flesh as it were I paid a visit to Bletchley Park, saw both three- and four-rotor machines and discovered that they possessed three Typex machines, a Mark III portable, a Mark 22 and a Mark 23, the latter two being variants of the Mark II with the Mark 23 being fitted to accept the CCM Adaptor. I spoke to one of the guides, was told that none of these machines were operational, introduced myself and was then introduced to Margaret Sale, wife of the then Director Tony Sale. She then introduced me to Brian Oakley, one of the Committee members and we had a long conversation, followed by some correspondence and a meeting with Tony Sale was arranged, for a day on which the Mark 22 would be out of its display cabinet for filming purposes so that I was able to get a close look at it. I noticed that a small part of the right-hand shift mechanism had at some time been incorrectly assembled, locking the right-hand printer in the lower case position. This could have been deliberate but I see no reason to do it if the mechanism is operating correctly. Whether deliberate or accidental I think that spotting this convinced Tony that my claims were genuine. After a further meeting later in the year at which I met the Trust Director Christine Large and the Museum Manager John Gallehawk, I started work on March 9th 2000, working six hours on one day a week.

Of the three machines the Mark 22 was clearly in the best condition and having been kept in a display cabinet appeared to be reasonably clean but I quickly discovered that this cleanliness was only 'skin deep' so to speak and did not extend to areas out of view of the cameras, nevertheless I was able to clean both printer units, the keyboard, the DC power supply and the base unit as complete assemblies but the drive unit and drum box were a different story. On the drive unit the main shaft, sleeve and shift-cam drums were so clogged with dried lubricant that they could barely be rotated and the whole assembly had to be stripped. The biggest problem was with the drum drive pawls: these are crimped or spun to one end of light alloy bushes which rotate on a steel shaft but three of the five were immovable, necessitating complete dismantling and it took a lot of persuasion, assisted by various penetrating fluids, to remove the bushes from the shaft which then required burnishing.

A few small parts were missing and I replaced these from the Mark 23 and from my own resources I manufactured a set of links for one plugboard. After lubrication and adjustment and some forty-three hours of work the machine was again operational.