BS 3692:2001 gives the general dimensions and tolerances of precision hexagon bolts, screws and nuts with ISO metric threads in diameters from 1.6 mm to 68 mm inclusive. Mechanical properties are given only in respect of carbon or alloy steel bolts, screws and nuts, which are not to be used for special applications, such as those requiring weldability, corrosion resistance or ability to withstand temperatures above 300 degrees C or below 50 degrees C.
The dimensional requirements of this standard also apply to non-ferrous and stainless steel bolts, screws and nuts.