The Colossus Rebuild Project by Tony Sale

Colossus Reborn

The Typewriter

On the original Colossus this was an IBM electric typewriter. These typewriters required a manual key press but then actuated the print arm via an electrical circuit and a rubber covered "throw" roller. In order to print automatically from the holding relays, a batch of puller selenoids was mounted under the typewriter. These pulled down the key arms as if they had been operated manually.

Later IBM models had selenoids built in so this was not necessary.

I was unable to obtain an early IBM typewriter but could get Flexowriters from the 1950s. These have exactly the same print mechanism as the IBM typewriters used on Colossus but have the extra paper tape read and punch attachments on the left hand side. These were not on the Colossus typewriters.

This page was originally created by the late Tony Sale, the original curator of the Bletchley Park Museum, and Secretary of the Bletchley Park Heritage Society.