The ground first thread pitch removes coarse swarf in the component and prevents premature fracture of the first thread pitch. Version to DIN 2279 - 2299.
For metric ISO threads, right-hand DIN 13.
Tolerances and dimensions to DIN ISO 1502.
Thread gauges for threads with other pitches, Whitworth, trapezoidal, round, UNC, UNF, NPT, and LH threads available on request.