The following table chart are standard metric external thread sizes M 0.25 - M 1.4 per. ANSI/ASME B1.13M-1995. These thread sizes and classes represent bolts and screws, as well, as other standard external threads. Do not use these values for standard metric internal thread design. All units in mm.
H = P ( 31/2 / 2 ) = 0.866025 P
0.125H = 0.108253P