Conversion inch / mm
| Inch, " |
Millimeter, mm |
No of threads per inch |
| UNC |
UN8 |
UNF |
| 1/8 |
3,175 |
40 |
- |
44 |
| 3/16 |
4,762 |
24 |
- |
32 |
| 1/4 |
6,35 |
20 |
- |
28 |
| 5/16 |
7,937 |
18 |
- |
24 |
| 3/8 |
9,525 |
16 |
- |
24 |
| 7/16 |
11,112 |
14 |
- |
20 |
| 1/2 |
12,7 |
13 |
- |
20 |
| 9/16 |
14,288 |
12 |
- |
18 |
| 5/8 |
15,875 |
11 |
- |
18 |
| 3/4 |
19,05 |
10 |
- |
16 |
| 7/8 |
22,225 |
9 |
- |
14 |
| 1 |
25,4 |
8 |
8 |
12 (14) |
| 1 1/8 |
28,575 |
7 |
8 |
12 |
| 1 1/4 |
31,75 |
7 |
8 |
12 |
| 1 3/8 |
34,925 |
6 |
8 |
12 |
| 1 1/2 |
38,1 |
6 |
8 |
12 |
| 1 5/8 |
41,275 |
- |
8 |
- |
| 1 3/4 |
44,45 |
- |
8 |
- |
| 1 7/8 |
47,625 |
- |
8 |
- |
| 2 |
50,8 |
4,5 |
8 |
- |
| 2 1/4 |
57,15 |
4,5 |
8 |
- |
| 2 1/2 |
63,5 |
4 |
8 |
- |
| 2 3/4 |
69,85 |
4 |
8 |
- |
| 3 |
76,2 |
4 |
8 |
- |
| 3 1/4 |
82,55 |
4 |
8 |
- |
| 3 1/2 |
88,9 |
4 |
8 |
- |
| 3 3/4 |
95,25 |
4 |
8 |
- |
| 4 |
101,6 |
4 |
8 |
- |