Bolts in metric dimensions or bolts with ISO thread

The thread diameters are graduated in millimetres, with an M in front of the diameter specification. The pitch - i.e. the distance from one thread to the next - is specified in fractions of a millimetre. A specification such as M12 x 1.25 therefore means that the thread has a diameter of 12 mm and the pitch is 1.25 mm. So much for the complete thread specification of a bolt with metric dimensions. In most cases, however, you will only find short designations such as M4, M6, M8 etc. This refers to the standardized metric threads according to ISO. Their pitches are

• M4 → 0.7 mm
• M5 → 0.8 mm
• M6 → 1.0 mm
• M8 → 1.25 mm
• M10 → 1.5 mm
• M12 → 1.75 mm

ISO threads are also the threads used on Harleys. We offer a selection of different finishes for the most commonly used ones.