D. Of bolt
T. per inch
Daim at Botton of thread
Area of Bottom of thread
Width across flats
Width across corners
Thickness of bolt head
nut
Ins.

Ins.
Ins. Sq.
Ins.
Ins.
Ins.
Ins.
1/4
20
.1860
.027
.525
.6062
.2187
1/4
5/16
18
.2414
.046
.6014
.6944
.2734
5/16
3/8
16
.2950
.068
.7094
.8191
.3281
3/8
7/16
14
.3460
.094
.8204
.9473
.3281
7/16
1/2
12
.3933
.121
.9191
1.0612
.4375
1/2
9/16
12
.4558
.164
1.011
1.1674
.4921
9/16
5/8
11
.5086
.203
1.101
1.2713
.5468
5/8
11/16
11
.5611
.256
1.2011
1.369
.6015
11/16
3/4
10
.6219
.304
1.3012
1.5024
.6562
3/4
13/16
10
.8644
.366
1.39
1.6050
.7109
13/16
7/8
9
.7327
.422
1.4788
1.7075
.7656
7/8
1
8
.7399
.554
1.6701
1.9284
.875