Enigma Development and Production History



While The Enigma Collection is a Web page for all kind of information about the German cipher machine Enigma, this page will concentrate more on the development and production history of the machine. Here I will post information concerning various aspects about the Enigma development, who were involved in the production and development of the various models, where were the machines produced and when.

The first documents are published because of popular demand, not because I feel these documents are the most important. They are TICOM reports giving information about the Enigma engineering office of Heimsoeth & Rinke (H&R) at Uhlandstr. 136 in Berlin and the second production site at the Ertel Werke at Hohenaschau, Chiemgau in Bavaria. H&R was visited twice, on 17 September and 17 November 1945, and Oberingenieur (Chief enigneer) Willi Korn and the design engineers Reinhold Schiele and Willi Schröder were interrogated or perhaps only questioned. The available reports do not contain the detailed interrogation information we are accustomed to from other TICOM interrogation reports. They contain no personal information about the people interviewed, for engineers Schiele and Schröder not even their first names are mentioned. Nor is it clear if the main production site in Berlin, the factory of Konski & Krüger, in Chausseestrasse 117 located in the Russian Zone, was visited or not; most likely it was not. The Russians on the other hand visited both the offices of H&R and the factory of Konski & Krüger, a fact that I already wrote about in May 2013, When the Russians Visited the Enigma Firm. Another article I wrote at that time presented the names and addresses of many of the workers at the factory of Konski & Krüger that we know worked on the production of the various Enigma models, The Workers Who Built the Enigma. Some of these workers had been involved with the Enigma from the very beginning in the mid 1920s and my hope was to trace some of these workers present relatives. I therefore also made a German version of this article in March 2016, Die Arbeiter, die die Enigma bauten, however so far nobody has come forward to say that one of their ancestors built the Enigma.

The report on the factory of the Ertel-Werk is undoubtedly the most interesting and detailed in the sense that it gives a lot of information about the production, mentioning the numbers produced, when and on which order numbers. It also describes in quite some detail the process of being selected as a second production facility and furthermore it mentions many of the subcontractors involved in the production of the Enigma. It states that the report was prepared in September 1945 by the then director of the Ertel-Werk für Feinmechanik (Ertel Factory for Precision Mechanics), Carl R. Preyß, however in our correspondence that took place in May and October 2008 he claims that he was not directly involved in the writing of this report. Apparently the report was based on his request to the American military administration in Bavaria for compensation for the seized and confiscated material that was removed from the Ertel-Werk factory by the US Army. I plan to publish a more detailed article about the Ertel-Werk and the people involved there at a later date.

Enigma TICOM reports

The Enigma Production

The TICOM report M-13 about the manufacturing of Enigma machines by H&R is also extremely interesting. The data it reveals about the Enigma production by H&R's manufacturing firm Konski & Krüger allow us to get a very good idea about the total production of the Wehrmacht plugboard Enigma machines. To ease the understanding of this data I have prepared an Excel sheet that gives a full overview of the production of K&K's facilities in Berlin and Geyer. You can download a PDF version or the Excel file here:

The files contain a detailed explanation of the data and the results that can be deduced from it. I repeat its main content here:

This compilation of Enigma production numbers is based mainly on the information given in the TICOM report M-13 entitled "Manufacture of Enigma Machines by Heimsoeth and Rinke, Berlin," however the data has been verified and corroborated with other information as far as possible. The Heeres Enigma serial numbers are exact only until the end of 1940, after that date the serial numbers have been extrapolated from the available production data. It is believed that the dates refer to the delivery date and not the exact production date that in most cases will be earlier. In total 20,306 Heeres Enigma machines were produced at Konski & Krüger (K&K) in Berlin; in addition, the TICOM report says that another approximately 3000 machines were produced by a firm named Geyer in Nuremberg. There was indeed a factory in Nuremberg with the name of Christian Geyer, Nürnberg-Süd, Nimrodstr. 10 doing production work for the Wehrmacht with the manufacturing code ajs. In June 2008 I sent a letter to the firm Geyer AG then still listed with the same address at Nimrodstr. 10, Nuremberg to hear if they would know anything about the firm's war time production, but I never received a reply. However, in the documents of Heimsoeth & Rinke there are references to Konski & Krüger's factory at Geyer in the district of Erzgebirge in Saxony. I therefore believe this is the production site referred to as Geyer and not the firm Geyer AG in Nuremberg.

The claim that 3000 machines were produced by Geyer on a separate block of serial numbers is both vague and odd. The report does not state if it refers to Heeres Enigma or Naval Enigma and seeing that the Naval Enigma machines produced at Konski & Krüger's Geyer factory is entered separately in the listing one gets the strong feeling that the TICOM people have got this wrong. It is indeed not the first time there are errors to be found in these reports. As we shall see the Geyer Naval Enigma machines were produced with the manufacturing code gvx, but no Heeres Enigma machines have been found with such a manufacturing code. Either the 3000 machines refer to the 300 naval Enigma machines produced by K&K at Geyer or the TICOM people possibly confused Geyer with either Olympia Büromaschinenwerke in Erfurt or the Ertel-Werk für Feinmechanik in Munich. Both firms produced approximately 3000 machines, Olympia delivered 3450 Naval Enigma while Ertel-Werk delivered 3360 Heeres Enigma machines on a special block of A-series serial numbers. These numbers use a fixed 5-digit format where the low numbers are padded with leading zeros such as A 00371/bac/43/E.

Ertel/Werk Enigma machine A 00371/bac/43/E

Ertel-Werk Enigma machine A 00371/bac/43/E.

The Naval Enigma serial numbers are exact until the end of 1943, after that date the serial numbers have been extrapolated in the same way as for the Heeres Enigma. In total K&K in Berlin produced 8200 Naval Enigma machines with another 300 machines produced at Geyer. Nothing is known about the serial numbers from the Geyer production apart from the fact that they were on a separate block of serial numbers. The manufacturing codes for the Enigma production at K&K was usually jla, the code allocated to Heimsoeth & Rinke (H&R). However, there is one clue for the serial numbers of these 300 Naval Enigma machines produced at Geyer in May to September 1944. A few naval machines that survived the end of the war have serial numbers in the range M 10028/gvx/44 to M 10297/gvx/44 and the code gvx is the manufacturing code for Konski & Krüger. The range from M 10001 to M 10300 would fit nicely with these 300 Geyer machines. Fifteen of these machines, with serial numbers from M 10119/gvx/44 to M 10300/gvx/44, are known to have been used in Norway during the war. If this is correct then there should be a gap in the serial numbers of produced machines from approximately M 8700 to M 10000; and this is indeed the case, no machine in this range has so far been discovered.

The other production site for the Naval Enigma was the factory of Olympia Büromaschinenwerke A.-G. in Erfurt allocated the manufacturing code aye. This factory, which started its naval Enigma production in 1943, produced 300 machines in 1943, 2870 machines in 1994 and finally 800 in 1945; a total of 3970 machines. If all machines were delivered is not known, however it is likely that both the 1943 and 1944 productions were completed with perhaps only a partial delivery in 1945. Again, looking at the machines that have been discovered after the war we find machines in the serial number range M 15118/aye/43 to M 18428/aye/45. It therefore seems that that the serial number block allocated to Olympia Büromaschinenwerke started at M 15001. This indicate that less than half of the 1945 production figure was reached and that only about 300 machines or so were delivered.

You can download an Excel listing of some surviving Enigma machines here:

With this information it is now possibly to get a better estimate of the total number of Enigma machines produced. For the Heeres Enigma we have 20,306 machines produced by K&K in Berlin. In addition to this the Ertel-Werk für Feinmechanik in Munich produced and delivered another 3360 machines, which gives a total of 23,666 Heeres Enigma machines. For the Naval Enigma K&K in Berlin produced 8200 machines with another 300 machines produced at Geyer, totalling 8500 machines. With the 3450 machines produced at Olympia Büromaschinenwerke we get a total of 11,950 Naval Enigma machines. These figures are conservative, the uncertainty is due to the exact number of machines that were produced and delivered at the very end of the war. When the Ertel-Werk firm was visited by the US Army they still had 80 Heeres Enigma machine at their factory that were completed and accepted, and another 70 machines completed but not yet accepted. Most likely similar situations existed at the other Enigma production sites.

Adding it all up we get a total of 35,616 Stecker Enigma machines of all types delivered to the Wehrmacht. As we can see it is less than half of the often-quoted number of 100,000 Enigma machines.

I have also prepared a listing of all the orders known to me that were placed by the Reichswehr and later the Wehrmacht for various Enigma models in the period 1926–1943. These machines were mainly for use by the armed forces but some were also for other government organisations such as the Reichsbahn and the various intelligence services.

Production Documents

A large collection of documents from Heimsoeth & Rinke and productions drawings from Konski & Krüger in Berlin and the Ertel-Werk für Feinmechanik in Munich were collected by the Allied TICOM teams that visited these places. Many of these original documents have survived and copies of some of them will be presented here for the first time.

A problem that frequently arises with old Enigma machines that have survived the war and now are in the collections of museums and private collectors is that the machines malfunction. Most of these problems are linked with poor or missing electrical connections in the electrical wiring maze of the machine. Electrically the Enigma machine uses a very simple circuit, however because it has a large number of contact points comprising keyboard contacts, plugboard connections, lamp connections and the many rotor contacts there are indeed many possible error sources.

Perhaps the most fragile part of the Enigma machine is the rotors and their connections. Especially the spring loaded contact pins are very fragile. Sometimes they get stuck in their depressed state due to grit or corrosion, and sometimes the springs or the pins themselves are broken. In such cases it is necessary to repair the rotor and replace the contact pin and its spring. As an aid in such repair I have decided to publish copies of the Enigma repair instructions prepared by Heimsoeth & Rinke's senior engineer Willi Korn in July 1933. To give a better feeling for the rotor construction I also add the engineering drawings of an Enigma rotor and a detailed drawing of the contact pins.


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The material described on these pages is created, collected, edited and published
by Frode Weierud, © March 2021

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