Dash Size
Inch Size
Nominal Thread Size
Male Thread (O.D.)
Female Thread (I.D.)
4
1/4"
9/16 -18
9/16" (.56)
.51"
6
3/8"
11/16 -16
11/16" (.68)
.63"
8
1/2"
13/16 -16
13/16" (.81)
.75"
10
1 -14
1" (1.00)
.93"
12
3/4"
1 3/16 -12
1 3/16" (1.18)
1.10"
16
1"
1 7/16 -12
1 7/16" (1.44)
1.36"
20
1 1/4"
1 11/16 -12
1 11/16" (1.68)
1.60"
24
1 1/2"
2 -12
2" (2.00)
1.92"