thread cuttingThread cutting is a process for generating a thread. It's used for the production of threads on the outer surface of a cylinder or on the inner surface of a bore. Tools used for thread cutting are the thread cutting die, the the screw tab or for serial production a process called cold or hot forming. There are many methods of generating threads, including subtractive methods (thread cutting and grinding) or deformative or transformative methods (rolling and forming; molding and casting).
The metric thread is the most widely used standardized thread geometry. The naming of metric threads uses an M which describes a nominal thread. For non standard metric threads the designation is different (e.g. for fine threads). The following number equals the nominal diameter.
The diameter of the core cylinder may be calculated as follows: nominal diameter - thread slope = core diameter. For example a M10 thread has a core diameter of 10mm - 1.5mm = 8.5mm. After boring a thread is cut in the cylinder. M10 describes the outer diameter of the screw.