Foreword
Committees responsible
Specification
1 Scope
2 Definitions
3 Symbols
4 Form of worm threads and wormwheel teeth
5 Information on worm gear elements
6 Formulae for calculation of dimensions
7 Accuracy of manufacture
8 Normal backlash
9 Load capacity
10 Efficiency and lubrication
11 Irreversibility
12 Information to be given on drawings
Appendices
A Typical wormwheel rim sections
B Examples of calculations
C Design procedure based on axial pitch of worm
Tables
1 Worm pitch tolerances
2 Worm profile tolerance
3 Worm thread thickness tolerance
4 Wormwheel pitch tolerance
5 Normal backlash
6 Worm gear zone factor Z
7 Basic stress factors for worm gears
8 Application factor KA
Figures
1 Normal section of basic rack (dimensioned in terms
    of axial module)
2 Entry gap in wormwheel teeth
3 Determination of q for maximum efficiency for any
    worm speed
4 Determination of q for worm speeds up to 300 r/min
5 Maximum value of addendum modification coefficient
    (X2,max)
6 Minimum value of addendum modification coefficient
    (X2,min)
7 Speed factor for worm gears (wear), Xc
8 Speed factor for worm gears (strength), Xb
9 Total equivalent running time and related life
    factors for wear and strength
10 Coefficient of friction for worm gears
11 Typical drawing of a worm
12 Typical drawing of a wormwheel
13 Wormwheel rim section
14 Minimum thickness of wormwheel rim section
15 Wormwheel rim section: alternative design of centre