BS 978-1:1968

Gears of pitch range greater than 20, up to 200 diametral pitch. Standard pitches; 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: single flank testing, calculation of measuring pin dimensions, calculations for various design conditions.Cross References:BS 978:Part 2BS 978:Part 3BS 978:Part 5 PD 3376Replaces BS 978:Part 1:1962.