Requirements of countersunk head screws with hexagon socket for sizes:
a) M3 to M24 with coarse pitches, and
b) M8 to M24 with the following fine pitches:
M8x1;
M10x1·25;
M12x1·5, M14x1·5, M16x1·5;
M18x2, M20x2, M22x2, M24x2.
IS 6761-1972 history
1973IS 6761-1972 Hexagon countersunk head screw specifications