Hamann Cartridge Thread

The Hamann Cartridge Thread is a historical thread used for optical and mechanical instruments, named after the German entrepreneur and pioneer in machine tool construction, August Hamann. The Hamann Cartridge Thread was widespread in the second half of the 19th century.

Contrary to its name, the Hamann Cartridge Thread has nothing to do with ammunition. The term refers to an old method of thread production, where cylindrical thread cartridges were attached to a spindle on a so-called cartridge lathe to cut the thread. The Hamann Cartridge Thread was designed for these thread cartridges.

The dimensions of the Hamann Cartridge Thread are challenging to capture in modern standards. It has no specific diameter, only pitch, and flank angle are defined. However, the Hamann Cartridge Thread is not straightforward, with threads per inch easily understood, but also complex fractions like 29 1/13 to contend with. The flank angle is 50° for almost all sizes, but there are exceptions at 64° or even 76°. The thread designation is relatively straightforward, with 13 sizes simply numbered. Only number 12 has two variants.