美制牙(UNF)
| 美制牙UNF | 牙數 | 下料孔徑 |
| NO.0 | 80 | 1.25 |
| NO.1 | 72 | 1.55 |
| NO.2 | 64 | 1.84 |
| NO.3 | 56 | 2.12 |
| NO.4 | 48 | 2.39 |
| NO.5 | 44 | 2.68 |
| NO.6 | 40 | 2.96 |
| NO.8 | 36 | 3.56 |
| NO.10 | 32 | 4.14 |
| NO.12 | 28 | 4.7 |
| 1/4 | 28 | 5.56 |
| 5/16 | 24 | 7 |
| 3/8 | 24 | 8.6 |
| 7/16 | 20 | 10 |
| 1/2 | 20 | 11.6 |
| 9/16 | 18 | 13 |
| 5/8 | 18 | 14.6 |
| 3/4 | 16 | 17.6 |
| 7/8 | 14 | 20.6 |
| 1” | 12 | 23.5 |
| 1-1/8 | 12 | 26.7 |
| 1-1/4 | 12 | 29.9 |
| 1-1/2 | 12 | 36.2 |





