Thread

Pitch of thread

Diameter of unthreaded shank

Width across flats

Width across corners

Diameter of washer face

Depth of washer face

Radius under head

Transition diameter

Thickness of head

p

ds

s

e

dw

c

r

da

k

coarse pitch series

max.

min.

max.

min.

min.

min.

max.

min.

min.

max.

max.

min.

M12

1.75

12.70

11.30

22.00

21.16

23.91

20.10

0.8

0.4

1.2

15.2

7.95

7.05

M16

2.0

16.70

15.30

27.00

26.16

29.56

24.90

0.8

0.4

1.2

19.2

10.75

9.25

M20

2.5

20.84

19.16

32.00

31.00

35.03

29.50

0.8

0.4

1.5

24.4

13.40

11.60

M22

2.5

22.84

21.16

36.00

35.00

39.55

33.30

0.8

0.4

1.5

26.4

14.90

13.10

M24

3.0

24.84

23.16

41.00

40.00

45.20

38.00

0.8

0.4

1.5

28.4

15.90

14.10

M27

3.0

27.84

26.16

46.00

45.00

50.85

42.80

0.8

0.4

2.0

32.4

17.90

16.10

M30

3.5

30.84

29.16

50.00

49.00

55.37

46.60

0.8

0.4

2.0

35.4

19.75

17.65

M36

4.0

37.00

35.00

60.00

58.80

66.44

55.90

0.8

0.4

2.0

42.4

23.55

21.45