Two Start Thread (Double Thread)

The 2N of a M10X1.5 2N designates the thread as a two start or is a double thread. Although it will be a bit more difficult to produce, a screw with two starting points is called a two start or double thread. A typical M10X 1.5 screw thread advances 1.5 mm in one revolution, but the two start or double thread advances twice the 3 mm of a normal screw thread.
For details, please refer to the explanation on the attached PDF file for details.