Initially we needed a total of 225 drums. A few of these were used on various displays etc. and a few are held as spares. 180 were for the first phase our rebuild; allowing five drum variations per Letchworth Enigma. We initially made a batch of 25, first to prove that we are on the right track and to encourage those who had to put in considerable work to complete the rest. At this stage we had sufficient to mount any known German Army or Air force menu. Later we decided to upgrade to being able to tackle German Navy Surface Fleet encryption. Three more drum types were needed but in this case we only made sufficient for one bank. That is 3 times 12 equal to 36. We therefore now have a grand total of 261.
The two images below are of our first drum.
Below is the ‘brush’ side.
Manufacture started with individual components.
Below is an image showing spun brass covers and main support discs. The covers were spun in Switzerland as arranged by Philip Bellamy. The covers came to us as just as blanks with a simple centre hole. Philip also arranged the tooling to drill the remaining holes. Members of our team then completed the drilling and finishing operations.
The main drum support discs were turned to inner and outer dimensions by Mike Hillyard from sheet material. Paul Kellar made a drilling jig for the complex hole pattern created directly from the original Tony Walden, AutoCad file. Members of the team then drilled all these discs.
We had all the brush pillars made commercially because of the large numbers and complexity. We also procured the very small 2-56 grub screws and 3-48 brass fixing nuts.
We completed over 20,000 brushes. All the ferrules were made and a very large amount of 0.008 inch diameter piano wire was cut up into one foot lengths. Jigs were then devised for cutting and crimping the wire. This process although very time consuming went very smoothly.