Dimensions, tolerances and general requirements for metric series spring washers of helical construction, for use with metric threaded fasteners within the range 1.6 mm to 68 mm diameter.Cross References:BS 21BS 427BS 856BS 860BS 970Supplement No. 1 to BS 1157BS 1449BS 1580BS 1706BS 1802BS 2061BS 2870BS 2873BS 3643:Part 1BS 3643:Part 2BS 3643:Part 3BS 3692BS 4168BS 4183BS 4185:Part 1BS 4185:Part 2BS 4186BS 4190BS 4219BS 4320BS 4377BS 4439BS 4463BS 9001DIN 127DIN 7980IS: 3063