Dash Size
Inch Size
Thread Size
Male Thread (O.D.)
Female Thread (I.D.)
2
1/8"
5/16-24
.31
.27
4
1/4"
7/16-20
.44
.39
6
3/8"
9/16-18
.56
.51
8
1/2"
3/4-16
.75
.69
12
3/4"
1 1/16-14
1.06
.98
16
1"
1 5/16-12
1.31
1.23
20
1 1/4"
1 5/8-12
1.63
1.54
24
1 1/2"
1 7/8-12
1.88
1.79
32
2"
2-12
2.5
2.42
