French thread
The French thread is a historical thread type that is now rarely used, also known as the System Français, abbreviated as S. F. It was later incorporated into the SI thread.
The French thread is a metric thread, with all dimensions in mm. The flank angle of the French thread is 60°.
The French thread is designated using a thread numbering system ranging from 0 to 19. In the range 0 to 9, there are one to two intermediate sizes between each number, which do not have their own number. For clear identification, the French thread designation can also include the external diameter and pitch, e.g., No. 2: 14 x 2.
The thread table for the French thread includes more than the 20 numbered threads due to the intermediate sizes, with a total of 34 different external diameters. Each thread size also has an associated core hole diameter, necessary for cutting an internal French thread and performing the necessary core hole drilling accurately. We can manufacture dies and taps for the French thread upon request.