常见 NPT 螺纹尺寸和底孔大小
| NPT 尺寸 | 螺纹外径 (mm) | 底孔直径 (mm) |
|---|---|---|
| 1/16 NPT | 7.938 | 6.5 |
| 1/8 NPT | 10.287 | 8.4 |
| 1/4 NPT | 13.716 | 11.5 |
| 3/8 NPT | 17.145 | 15.0 |
| 1/2 NPT | 21.336 | 18.6 |
| 3/4 NPT | 26.670 | 23.1 |
| 1 NPT | 33.401 | 29.5 |
| 1-1/4 NPT | 42.164 | 38.0 |
| 1-1/2 NPT | 48.261 | 43.5 |
| 2 NPT | 60.325 | 55.0 |
尺寸可从 SolidWorks 等这类的软件中测得，锥形孔螺纹 —> ANSI Inch 标准
常见 G 螺纹尺寸和底孔大小
| G 螺纹尺寸 | 螺纹外径 (mm) | 底孔直径 (mm) |
|---|---|---|
| G 1/8 | 9.728 | 8.8 |
| G 1/4 | 13.157 | 11.8 |
| G 3/8 | 16.662 | 15.25 |
| G 1/2 | 20.955 | 19.0 |
| G 5/8 | 22.911 | 21.0 |
| G 3/4 | 26.441 | 24.0 |
| G 1 | 33.249 | 30.75 |
| G 1-1/4 | 41.91 | 39.0 |
| G 1-1/2 | 47.803 | 44.5 |
| G 2 | 59.614 | 56.0 |
直管螺纹孔，ISO 标准
常见 Rc 螺纹尺寸和底孔大小
注意，R 螺纹是锥形外螺纹，Rc 螺纹是锥形内螺纹
| Rc 螺纹尺寸 | 螺纹外径 (mm) | 底孔直径 (mm) |
|---|---|---|
| Rc 1/8 | 9.728 | 8.0 |
| Rc 1/4 | 13.157 | 10.5 |
| Rc 3/8 | 16.662 | 14.0 |
| Rc 1/2 | 20.955 | 17.5 |
| Rc 3/4 | 26.441 | 23.0 |
| Rc 1 | 33.249 | 29.0 |
| Rc 1-1/4 | 41.91 | 38.0 |
| Rc 1-1/2 | 47.803 | 43.5 |
| Rc 2 | 59.614 | 55.0 |
尺寸可从 SolidWorks 等这类的软件中测得，锥形孔螺纹 —> ISO 标准
UNF 螺纹
螺纹孔，标准选美标英制。ANSI Inch 是指基于 ANSI 标准（American National Standards Institute，美国国家标准协会）规定的，以英寸为单位的机械和工业标准
