BS 6168:1987

This British Standard specifies dimensional, accuracy and material requirements for spur gears made from non-metallic materials in pitch sizes of 0.50 module to 50 module (48 to 0.50 diametral pitch) and also gives guidance on lubrication and lists information to be given on drawings. The ranges of modules and diametral pitches employed include those specified in BS 436-1 and BS 436-2. The basic tooth form and the accuracy grades specified are selected from those specified in BS 436-1 and BS 436-2. Helical gears are not within the scope of this standard.

Surface finish requirements for thermoplastics gears are not specified in this standard as insufficient authoritative data on the subject exists at present.

NOTE 1 Information on the selection of materials and the lubrication of plastics gears is given in Appendix A and Appendix B, respectively. Tables of tolerance values are given in Appendix C. Recommendations for addendum modification and a recommended method of gear stressing are given in Appendix D and Appendix F. Example calculations are given in Appendix E and Appendix F.

NOTE 2 The titles of the publications referred to in this standard are listed on the inside back cover.

Dimensional accuracy and material requirements for spur gears in the pitch sizes of 0.5 module to 50 module (48 to 0.5 dp)