Multi Tooth Lock WasherIS : 5371 - 5556
Covers the requirements for multi-tooth lock washers for use with screws in the diameter range 1.6 to 30mm.
The multi-tooth lock washers shall be of the following three types:
- Type A- Externally toothed
- Type B- Internally toothed
- Type C- Countersunk
The multi-tooth lock washer shall confirm to precision grade of IS: 5369-1975 'General requirements for plain washers and lock washers'.
The multi-tooth lock washers shall be made from carbon spring steel of any suitable grade specified in IS: 4072-1975 ‘Specification for steel for spring washers’.
The multi-tooth lock washers made of spring steel shall be suitably hardened and tempered to result in a hardness range of 410 to 490 HV or 42 to 49 HRC. Vicker’s hardness tested in accordance with IS: 1501-1968 ‘Method for vicker’s hardness test for steel (first revision)’. Shall be taken as the reference value.
The multi-tooth lock washers shall be supplied in natural black finish unless otherwise specified by the specified by the purchaser. At the request of the purchaser, lock washers may be phosphate, tinned, galvanized, nickel plated, copper plated, cadmium plated, etc.
Plated lock washers shall be stress relieved after plating to avoid hydrogen embrittlement and shall be subjected to an embrittlement test.