Böllhoff Hand taps for HELICOIL® plus Nick Hand Taps for through holes. For standard threads up to P = 2 mm, for fine increases to P = 3 mm. For machining materials up to 700 N / mm2 strength. For blind holes only if sufficient chip space is available. Core drill hole at least 1 d deeper than the fully cut thread length. Nominal thread diameter d: M6