Cypher machines maintenance and restoration spanning sixty years

Cryptologia, Jul 2003 by Clarkson, Dorothy

As with the Lorenz the only information available was that found in Cryptologia. I cannot quote the reference as I no longer have a copy of the article. The machine has an integral D. C. power supply for the relays but requires additional external supplies and a connection unit but as I had no information on any of these was unable to do more than clean, re-lubricate and ensure that all mechanical parts moved freely and smoothly. Finally I produced wiring data sheets similar to those that I had written for the Lorenz. I don't really know how long I spent on this machine as all the wiring checks were done in my own workshop but it was eventually returned to its display cabinet on 12th July 2001.

That completed my work on Bletchley Park's cypher machines but I was then asked if I would like to 'have a go' at refurbishing a Hollerith Type 313/0 Card Sorter. Similar machines were used at the Park during the war for sorting and collating the mass of information collected but this machine is post-war, probably early to mid-fifties. I had never seen one before and there was no information available but it is an electro-mechanical machine and I agreed to see what I could do. I have since discovered that there is a manual in the archives but this was not known at the time.

I started by making sketches then piece by piece dismantled and cleaned the mechanical components, labelling each item and its associated fixings and marking their positions on the appropriate sketch. Next step was to clean and check the electrical components and wiring and produce wiring sheets and circuit diagrams. From all this I was able to deduce how the machine operated and after re-assembly and some adjustments persuaded it to run but it would not feed or sort cards. I was then put in touch with two ex-IBM/Hollerith service engineers who were persuaded to visit the Park, apply their expertise to the machine and impart some of their knowledge to me.

A small number of old cards were found elsewhere in the Museum and the machine was set up and ran successfully using these but unfortunately most were damaged or destroyed in the process. We were then presented with a box of new cards designed for naval use but the machine did not like these, trying to feed two at a time so we were more or less back to square one and had to repeat the whole setting up procedure. This done, the machine developed an electrical fault which I was left to sort out and was eventually able to demonstrate the machine to a number of Volunteers and visitors on 19th September 2002.

I have since discovered that the new cards are approximately one thousandth of an inch thinner than the old ones which demonstrates the accuracy with which the machine has to be set up.

Dorothy Clarkson*

ADDRESS: 2 Furlong Crescent, Bishopstone, Aylesbury Bucks HP17 8SG ENGLAND.

* Written 1 October 2002.

BIOGRAPHICAL SKETCH

The author served in the Royal Air Force from 1937-1952, first as an apprentice and then as a Wireless Electrical Mechanic. From 1953-1986 the author served the company, Rediffusion Simulation Limited as a Senior System Design Engineer. The work for Bletchley Park came about quite fortuitously and has now been completed.