Popular sizes:
| Thread | Pitch, mm | Bar ⌀, mm | Tolerance |
|---|---|---|---|
| М2 | 0.40 (coarse) | 1.92 | −0.10 / −0.04 |
| М2.5 | 0.45 (coarse) | 2.41 | −0.10 / −0.04 |
| М3 | 0.50 (coarse) | 2.90 | −0.10 / −0.04 |
| 0.35 (fine) | 2.93 | −0.10 / −0.04 | |
| М3.5 | 0.60 (coarse) | 3.38 | −0.15 / −0.06 |
| М4 | 0.70 (coarse) | 3.86 | −0.15 / −0.06 |
| 0.50 (fine) | 3.90 | −0.15 / −0.06 | |
| М5 | 0.80 (coarse) | 4.84 | −0.15 / −0.06 |
| 0.50 (fine) | 4.90 | −0.15 / −0.06 | |
| М6 | 1.00 (coarse) | 5.80 | −0.15 / −0.06 |
| 0.75 (fine) | 5.85 | −0.15 / −0.06 | |
| М7 | 1.00 (coarse) | 6.80 | −0.25 / −0.10 |
| М8 | 1.25 (coarse) | 7.75 | −0.25 / −0.10 |
| 1.00 (fine) | 7.80 | −0.25 / −0.10 | |
| М10 | 1.50 (coarse) | 9.70 | −0.25 / −0.10 |
| 1.25 (fine) | 9.75 | −0.25 / −0.10 | |
| М12 | 1.75 (coarse) | 11.65 | −0.25 / −0.10 |
| 1.50 (fine) | 11.70 | −0.25 / −0.10 | |
| М14 | 2.00 (coarse) | 13.60 | −0.35 / −0.15 |
| 1.50 (fine) | 13.70 | −0.35 / −0.15 | |
| М16 | 2.00 (coarse) | 15.60 | −0.35 / −0.15 |
| 1.50 (fine) | 15.70 | −0.35 / −0.15 | |
| М18 | 2.50 (coarse) | 17.50 | −0.35 / −0.15 |
| 1.50 (fine) | 17.70 | −0.35 / −0.15 | |
| М20 | 2.50 (coarse) | 19.50 | −0.35 / −0.15 |
| 1.50 (fine) | 19.70 | −0.35 / −0.15 | |
| М22 | 2.50 (coarse) | 21.50 | −0.35 / −0.15 |
| 1.50 (fine) | 21.70 | −0.35 / −0.15 | |
| М24 | 3.00 (coarse) | 23.40 | −0.60 / −0.25 |
| 2.00 (fine) | 23.60 | −0.60 / −0.25 | |
| М27 | 3.00 (coarse) | 26.40 | −0.60 / −0.25 |
| 2.00 (fine) | 26.60 | −0.60 / −0.25 | |
| М30 | 3.50 (coarse) | 29.30 | −0.60 / −0.25 |
| 2.00 (fine) | 29.60 | −0.60 / −0.25 | |
| М33 | 3.50 (coarse) | 32.30 | −0.60 / −0.25 |
| 2.00 (fine) | 32.60 | −0.60 / −0.25 | |
| М36 | 4.00 (coarse) | 35.20 | −0.60 / −0.25 |
| 3.00 (fine) | 35.40 | −0.60 / −0.25 | |
| М39 | 4.00 (coarse) | 38.20 | −1.00 / −0.40 |
| 3.00 (fine) | 38.40 | −1.00 / −0.40 | |
| М42 | 4.50 (coarse) | 41.10 | −1.00 / −0.40 |
| 3.00 (fine) | 41.40 | −1.00 / −0.40 | |
| М45 | 4.50 (coarse) | 44.10 | −1.00 / −0.40 |
| 3.00 (fine) | 44.40 | −1.00 / −0.40 | |
| М48 | 5.00 (coarse) | 47.00 | −1.00 / −0.40 |
| 3.00 (fine) | 47.40 | −1.00 / −0.40 |
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Popular sizes:
| Thread | TPI | Bar ⌀ | Tolerance |
|---|---|---|---|
| #2-56 UNC | 56 | 0.080″ / 2.03 | −0.002″ |
| #2-64 UNF | 64 | 0.082″ / 2.08 | −0.002″ |
| #3-48 UNC | 48 | 0.094″ / 2.39 | −0.002″ |
| #3-56 UNF | 56 | 0.097″ / 2.46 | −0.002″ |
| #4-40 UNC | 40 | 0.111″ / 2.82 | −0.002″ |
| #4-48 UNF | 48 | 0.112″ / 2.84 | −0.002″ |
| #5-40 UNC | 40 | 0.124″ / 3.15 | −0.002″ |
| #5-44 UNF | 44 | 0.125″ / 3.18 | −0.002″ |
| #6-32 UNC | 32 | 0.137″ / 3.48 | −0.002″ |
| #6-40 UNF | 40 | 0.139″ / 3.53 | −0.002″ |
| #8-32 UNC | 32 | 0.163″ / 4.14 | −0.002″ |
| #8-36 UNF | 36 | 0.164″ / 4.17 | −0.002″ |
| #10-24 UNC | 24 | 0.187″ / 4.75 | −0.002″ |
| #10-32 UNF | 32 | 0.188″ / 4.78 | −0.002″ |
| #12-24 UNC | 24 | 0.213″ / 5.41 | −0.002″ |
| #12-28 UNF | 28 | 0.215″ / 5.46 | −0.002″ |
| 1/4″-20 UNC | 20 | 0.240″ / 6.10 | −0.002″ |
| 1/4″-28 UNF | 28 | 0.243″ / 6.17 | −0.002″ |
| 5/16″-18 UNC | 18 | 0.302″ / 7.67 | −0.002″ |
| 5/16″-24 UNF | 24 | 0.306″ / 7.77 | −0.002″ |
| 3/8″-16 UNC | 16 | 0.364″ / 9.25 | −0.003″ |
| 3/8″-24 UNF | 24 | 0.369″ / 9.37 | −0.002″ |
| 7/16″-14 UNC | 14 | 0.425″ / 10.80 | −0.003″ |
| 7/16″-20 UNF | 20 | 0.430″ / 10.92 | −0.003″ |
| 1/2″-13 UNC | 13 | 0.487″ / 12.37 | −0.003″ |
| 1/2″-20 UNF | 20 | 0.493″ / 12.52 | −0.003″ |
| 9/16″-12 UNC | 12 | 0.548″ / 13.92 | −0.004″ |
| 9/16″-18 UNF | 18 | 0.555″ / 14.10 | −0.003″ |
| 5/8″-11 UNC | 11 | 0.610″ / 15.49 | −0.004″ |
| 5/8″-18 UNF | 18 | 0.618″ / 15.70 | −0.003″ |
| 3/4″-10 UNC | 10 | 0.733″ / 18.62 | −0.004″ |
| 3/4″-16 UNF | 16 | 0.741″ / 18.82 | −0.003″ |
| 7/8″-9 UNC | 9 | 0.857″ / 21.77 | −0.004″ |
| 7/8″-14 UNF | 14 | 0.866″ / 22.00 | −0.004″ |
| 1″-8 UNC | 8 | 0.982″ / 24.94 | −0.005″ |
| 1″-12 UNF | 12 | 0.989″ / 25.12 | −0.004″ |
| 1 1/8″-7 UNC | 7 | 1.105″ / 28.07 | −0.005″ |
| 1 1/4″-7 UNC | 7 | 1.230″ / 31.24 | −0.005″ |
| 1 1/2″-6 UNC | 6 | 1.476″ / 37.49 | −0.006″ |
More standards, diameters and pitches in the mobile app
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Popular sizes:
| Thread | TPI | Bar ⌀, mm | Tolerance |
|---|---|---|---|
| G 1/16 | 28 TPI | 7.65 | −0.08 / −0.03 |
| G 1/8 | 28 TPI | 9.65 | −0.10 / −0.04 |
| G 1/4 | 19 TPI | 13.10 | −0.10 / −0.04 |
| G 3/8 | 19 TPI | 16.55 | −0.10 / −0.04 |
| G 1/2 | 14 TPI | 20.85 | −0.12 / −0.05 |
| G 5/8 | 14 TPI | 22.85 | −0.12 / −0.05 |
| G 3/4 | 14 TPI | 26.30 | −0.12 / −0.05 |
| G 7/8 | 14 TPI | 30.20 | −0.15 / −0.06 |
| G 1 | 11 TPI | 33.05 | −0.15 / −0.06 |
| G 1 1/8 | 11 TPI | 37.55 | −0.15 / −0.06 |
| G 1 1/4 | 11 TPI | 41.70 | −0.15 / −0.06 |
| G 1 1/2 | 11 TPI | 47.60 | −0.15 / −0.06 |
| G 2 | 11 TPI | 59.45 | −0.20 / −0.08 |
| G 2 1/2 | 11 TPI | 75.05 | −0.25 / −0.10 |
| G 3 | 11 TPI | 87.85 | −0.25 / −0.10 |
More standards, diameters and pitches in the mobile app
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Popular sizes:
| Thread | TPI | Bar ⌀, mm | Tolerance |
|---|---|---|---|
| R 1/16 | 28 TPI | 7.72 | +0.05 / −0.05 |
| R 1/8 | 28 TPI | 9.73 | +0.05 / −0.05 |
| R 1/4 | 19 TPI | 13.16 | +0.05 / −0.05 |
| R 3/8 | 19 TPI | 16.66 | +0.05 / −0.05 |
| R 1/2 | 14 TPI | 20.96 | +0.07 / −0.07 |
| R 3/4 | 14 TPI | 26.44 | +0.07 / −0.07 |
| R 1 | 11 TPI | 33.25 | +0.10 / −0.10 |
| R 1 1/4 | 11 TPI | 41.91 | +0.10 / −0.10 |
| R 1 1/2 | 11 TPI | 47.80 | +0.10 / −0.10 |
| R 2 | 11 TPI | 59.61 | +0.13 / −0.13 |
| R 2 1/2 | 11 TPI | 75.18 | +0.13 / −0.13 |
| R 3 | 11 TPI | 87.88 | +0.13 / −0.13 |
More standards, diameters and pitches in the mobile app
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Popular sizes:
| Thread | TPI | Bar ⌀, mm | Tolerance |
|---|---|---|---|
| NPT 1/16 | 27 TPI | 7.85 | +0.05 / −0.05 |
| NPT 1/8 | 27 TPI | 10.20 | +0.05 / −0.05 |
| NPT 1/4 | 18 TPI | 13.65 | +0.05 / −0.05 |
| NPT 3/8 | 18 TPI | 17.10 | +0.05 / −0.05 |
| NPT 1/2 | 14 TPI | 21.25 | +0.07 / −0.07 |
| NPT 3/4 | 14 TPI | 26.55 | +0.07 / −0.07 |
| NPT 1 | 11.5 TPI | 33.30 | +0.10 / −0.10 |
| NPT 1 1/4 | 11.5 TPI | 41.95 | +0.10 / −0.10 |
| NPT 1 1/2 | 11.5 TPI | 48.10 | +0.10 / −0.10 |
| NPT 2 | 11.5 TPI | 59.95 | +0.13 / −0.13 |
| NPT 2 1/2 | 8 TPI | 72.50 | +0.15 / −0.15 |
| NPT 3 | 8 TPI | 88.40 | +0.15 / −0.15 |
More standards, diameters and pitches in the mobile app
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See also
Before cutting an external thread with a die, the stock bar is turned down to a diameter slightly below the nominal thread size. The die displaces material outward — if the stock is too thick, the die binds or the thread tears.
Rule of thumb: bar ⌀ ≈ nominal − (0.1…0.3) mm, depending on pitch and material.