Enigma Replica – Construction

Substitution encryption How it works? Construction

First of all, we downloaded on the website enigma.hs-weingarten.de all the technical drawings of a current Enigma Machine.

Name Material
Keyboard and Sub-keyboard Wood
Rotors 3D printed
Compensator 3D printed in 3 parts

How do we build the whole thing

At this time, the best solution is to have a look at Solidworks files available on Google Drive: https://drive.google.com/open?id=0ByDt0-mUVk45R3BvcGstb21YUG8
In this folder, there are several SLDASM files that will allow you to see how the whole Enigma prototype is built.


We could not build a current Enigma switch; therefore, we decided to use a basic micro switch as it can be found online (for instance, on Digikey). For the keys, we use an aluminium pipe (6mm diameter) with a 3D-printed touch at the top and the letter drawn by hand. For the keyboard (made in steel in the original version), we designed a keyboard from 3 layers of plywood of 5mm each. These 3 layers are glued together and drilled afterwards.

Rotors and reflector

Rotors and reflector were designed on Solidworks from the datasheet of the current Enigma machine and 3D-printed afterwards. For the pins, we use brass bought in cylinder and rectangular profiles of 5mm. We cut the profiles in little parts and weld it with tin. Then, we put these tiny brass parts in the rotor and we closed it with glue. We then used a belt sander to make each one flat and at the same height.


Currently, we have an error on this assembled rotor/reflector:

  • The reflector is not locked on the bearing block (the part on the right side holding the axis).
  • Same issue on the other side 😦
  • Our pins are not close enough to the female pins: the current does not flow properly on all connections.

Lamps holder

The current Enigma Machine used E10 filament Lamp (RS link). We want a low-cost replica: we use extrabright LEDs (available from Sparkfun, RS and others). LEDs are connected with a 1KΩ resistor to limit the input current. The current lamp holder is made of metal, ours is made from plywood.


Current status (mid-July)

Here are some pictures of the prototype as it is in mid-July. As it was a student project, some students should work on it in the next academic year.