UNC Thread Dimensions
25 Unified National Coarse designations with pitch, TPI, minor diameters and tap drill size.
Dimensions
millimetres unless stated| Designation | TPI | Major (mm) | Minor ext (mm) | Tap drill (mm) |
|---|---|---|---|---|
| #1-64 UNC | 64 | 1.85 | -10.51 | -8.23 |
| #2-56 UNC | 56 | 2.18 | -11.95 | -9.34 |
| #3-48 UNC | 48 | 2.51 | -13.98 | -10.93 |
| #4-40 UNC | 40 | 2.84 | -16.94 | -13.28 |
| #5-40 UNC | 40 | 3.17 | -16.61 | -12.95 |
| #6-32 UNC | 32 | 3.51 | -21.23 | -16.65 |
| #8-32 UNC | 32 | 4.17 | -20.57 | -15.99 |
| #10-24 UNC | 24 | 4.83 | -28.15 | -22.05 |
| #12-24 UNC | 24 | 5.49 | -27.49 | -21.39 |
| 1/4-20 UNC | 20 | 6.35 | -33.23 | -25.91 |
| 5/16-18 UNC | 18 | 7.94 | -36.04 | -27.9 |
| 3/8-16 UNC | 16 | 9.52 | -39.95 | -30.8 |
| 7/16-14 UNC | 14 | 11.11 | -45.43 | -34.97 |
| 1/2-13 UNC | 13 | 12.7 | -48.19 | -36.93 |
| 9/16-12 UNC | 12 | 14.29 | -51.67 | -39.48 |
| 5/8-11 UNC | 11 | 15.88 | -56.08 | -42.78 |
| 3/4-10 UNC | 10 | 19.05 | -60.1 | -45.47 |
| 7/8-9 UNC | 9 | 22.22 | -65.72 | -49.46 |
| 1-8 UNC | 8 | 25.4 | -73.54 | -55.24 |
| 1-1/8-7 UNC | 7 | 28.57 | -84.5 | -63.59 |
| 1-1/4-7 UNC | 7 | 31.75 | -81.33 | -60.42 |
| 1-3/8-6 UNC | 6 | 34.92 | -97 | -72.6 |
| 1-1/2-6 UNC | 6 | 38.1 | -93.82 | -69.43 |
| 1-3/4-5 UNC | 5 | 44.45 | -113.86 | -84.58 |
| 2-4-1/2 UNC | 4.5 | 50.8 | -125.09 | -92.57 |