Index Typewriter - AEG Mignon

This project is based on the AEG Mignon Model 4 typewriter (1923). The first model of the Mignon was designed circa 1901-1903 by the German company AEG, and subsequent versions found some popularity in Europe as an affordable alternative to fully keyed typewriters. They also offered the unique feature of interchangeable typefaces. Up against ever improving mass production of conventional typewriters, and an increasing supply of used office machines, the Mignon ended production 1932.

This style of machine is called an “index” typewriter. A stylus is pointed at a character on an index, which orients a single type element that strikes the paper with the press of a lever. A fair warning that this is a somewhat slow way of typing. While 1 character per second is easily achievable, beyond 2 becomes increasingly difficult.

With many months of work and many revisions, I have tried to make this project as accessible as possible. No glue is required, all parts can be printed without support*, and small clearances have been added to limit post processing. Take note of requirements and recommendations, download Hardware and Printing Guide before proceeding. I recommend testing and dialing in settings for the "Mounting Screws" before printing anything else, test at least one with the "Baseplate Thread Test".

I will do my best to be responsive to problems and redesign parts if needed. Please consider sharing your make!

Requirements:

• Minimum XYZ build volume of 250 x 210 x 220 mm

• TPU or other flexible filament (I used TPU 95A, slightly lower durometers may work better)

• Assortment of small compression and extension springs (search for 200 piece assortment)

• 4 pieces of ~ 2.5 mm rigid wire (source from coat hangers)

• Universal ½” typewriter ribbon

• Computer printer OR multi-material 3D printer

Recommended:

• XYZ build volume of 250 x 220 x 247 mm

• 0.2 mm nozzle OR resin printer

• Torx T20 and T30 drivers

*The smaller Baseplate file has a ~40 mm bridge on its outer wall and may benefit from support. Several parts require brims for proper bed adhesion.

12/13/25 Update: Carriage Plate Right, Carriage Plate Left, Typing Lever, Space Lever have stronger spring mounting pegs.