This specification applies to metric series, single-coil carbon steel helical spring lock washers of —
(a) the loose over-the-thread type, to suit fasteners in the diameter range 3-36 mm inclusive, and
(b) the captive type to suit fasteners in the diameter range 3-10 mm inclusive.
The washers are mainly intended for use in general engineering and automotive applications, with right-hand screw threads. Helical spring lock washers for use with left-hand screw threads are also covered by this specification, except that the helix will be reversed.
NOTE: The captive lock washers specified are suitable for use with fasteners with ISO Metric coarse series screw threads only.