Thread

Pitch of thread

Width across flats

Width across corners

Diameter of washer face

Depth of   washer face

Thickness of nut

dia.

p

s

e

dw

c

m

size

(coarse   pitch series)

max.

min.

min.

min.

max.

max.

min.

M12

1.75

21.00

20.16

22.78

19.20

0.8

13.10

12.00

M16

2.0

27.00

26.16

29.56

24.90

0.8

17.10

16.40

M20

2.5

32.00

31.00

36.90

29.50

0.8

21.30

20.00

M22

2.5

36.00

35.00

41.60

33.30

0.8

23.60

22.30

M24

3.0

41.00

40.00

47.30

38.00

0.8

24.20

22.90

M27

3.0

46.00

45.00

53.10

42.80

0.8

27.60

26.30

M30

3.5

50.00

49.00

57.70

46.50

0.8

30.70

29.10

M36

4.0

60.00

58.80

69.30

55.90

0.8

36.60

35.00