The possibility of re-building a Bombe was discussed very early on by
Tony Sale and the Committee of the Computer Conservation Society.
It began to become a realistic possibility when a set of drawings of the
wartime Bombe and some reports were released to Tony Sale by GCHQ in 1995. These drawings
were all of piece parts for the Bombe with no assembly drawings and John Harper
recently retired from the computer company ICL agreed to have a look at them and
start a "gathering of information" phase including locating and talking to
engineers who worked at the British Tabulating Machine company (BTM) at Letchworth, where the Bombes were made.
This received a big impetus from a "Punched Card Reunion" of ex ICL staff
in October 1996 which John Harper addressed and from which he received many offers of
A crucial factor was the discovery in November 1996 by Tony and Margaret Sale in the American
National Archive of the 1944 US 6812 Army Division report on the Bombe.
This report gave a detailed account of the setting up, running and maintenance
of the Bombes being run by American service men in a wing at Eastcote in
North London. It also included test menus and a large set of photographs.
So now it was possible to see how all the piece part drawings might go
together and a rebuild became a possibility.
Tony Sale had already made contact with Quantel Ltd, a computer graphics
company, for support for the rebuild of the Colossus computer. They were
enthusiastic about a Bombe rebuild and agreed to provide start-up funds for it.
The Computer Conservation Society agreed to host the Bombe rebuild so that it
could benefit from the British Computer Society's Charitable status and
a bank account was opened on 10th February 1997 and the Bombe Rebuild Project
came into being.
The Bletchley Park Trust agreed to make available Hut 11, the original
Bombe room in Bletchley Park, provided that the Bombe Rebuild Project
re-furbished it, which it did, at a cost of 5,000 pounds sterling and
set up a workshop area.
It was agreed that Tony Sale and an assistant would try to build a
checking machine as a first step. This would allow some rebuild techniques
to be tried out on a small scale prior to a complete Bombe rebuild.
During 1997 John Harper and his band of volunteers transferred the GCHQ
drawings to CAD and overall assembly drawings were re-created.
John Harper was helped in this by resources being
made available from the Northern Telegraph Company (NORTEL) who had
direct links to the original BTM company. In 1998, NORTEL's Technical Director,
Alan Fox, presented the Project with a further cash donation to cover
the mounting costs of machining parts for the Bombe.
Many of the WRNS who operated the Bombes during the War made donations
to the Bombe Project which were gratefully received.
When, in 1999, Tony Sale was no longer Museums Director the Bletchley Park
end of the project was wound down and John Harper took over the project.
The results of his labours can be seen on his web site
and a considerable part of the Bombe should soon be on display in Hut 11
in Bletchley Park.
This page was originally created by the late Tony Sale the
original curator of the Bletchley Park Museum