Heavy Thumb Screw (type A)                        ANSI/ASME B18.17

Nomial size

Threads per Inch

Head Width(A)

Head Height(B)

Head Thickness(C)

Head Thickness

Shoulder Dia.(E)

Practical Screw Lengths(L)

Max

Max

Max

Min

Max

Min

Max

Min

Max

Min

Max

Min

10

24

.89

.83

.84

.72

.18

.16

.10

.08

.33

.31

2.00

.50

1/4

20

1.05

.99

.94

.81

.24

.22

.10

.08

.40

.38

3.00

.50

5/16

18

1.21

1.15

1.00

.88

.27

.25

.11

.09

.46

.44

4.00

.50

3/8

16

1.41

1.34

1.16

1.03

.30

.28

.11

.09

.55

.53

4.00

.50

7/16

14

1.59

1.53

1.22

1.09

.36

.34

.13

.11

.71

.69

2.50

1.00

1/2

13

1.81

1.72

1.28

1.16

.40

.38

.14

.12

.83

.81

3.00

1.00