Covers gears having modules of 1 mm and less including first and second preferences. Two basic racks (one with backlash allowance); modification of addendum and centre distance to suit various conditions. Four grades of accuracy with elemental and dual flank composite test tolerances. Appendices give information on single flank testing, calculation of measuring pin dimensions and examples of calculations for various design conditions. Metric equivalent of BS 978-1.Cross References:BS 308BS 978:Part 1BS 978:Part 2BS 2519BS 4500