---
type: "thread-series"
series: "metric-fine"
name: "ISO Metric Fine"
system: "metric"
size_count: 37
smallest: "M1.6×0.2"
largest: "M64×4"
standard: "ISO 68-1, ISO 261, ISO 262, ISO 965-1, ISO 898-1"
verified: "August 1, 2026"
url: https://shopmath.org/threads/metric-fine
---

# ISO Metric Fine Thread Chart — All 37 Sizes, Dimensions & Tap Drills

The ISO Metric Fine series covers 37 standard sizes, from M1.6×0.2 to M64×4, and 37 of them carry a tap drill recommendation. ISO 261 fine metric pitches, for thin walls and vibration resistance.

- **Sizes**: 37
- **Smallest**: M1.6×0.2
- **Largest**: M64×4
- **Standard**: ISO 68-1, ISO 261, ISO 262, ISO 965-1, ISO 898-1

## Every Metric fine Thread Size — Dimensions and Tap Drills

Ordered smallest to largest. Every row links to the full page for that thread, with class limits, clearance holes and tap drills across 50–85% engagement.

| Thread | Pitch (mm) | Major Ø (in) | Major Ø (mm) | Pitch Ø (in) | Pitch Ø (mm) | Minor Ø (in) | Minor Ø (mm) | Tap drill | Tap drill Ø (in) | Tap drill Ø (mm) |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| [M1.6×0.2](https://shopmath.org/threads/metric-fine/m1.6x0.2.md) | 0.200 | 0.0630 | 1.600 | 0.0579 | 1.470 | 0.0544 | 1.383 | 1.4 mm | 0.0551 | 1.400 |
| [M1.8×0.2](https://shopmath.org/threads/metric-fine/m1.8x0.2.md) | 0.200 | 0.0709 | 1.800 | 0.0658 | 1.670 | 0.0623 | 1.583 | 1.6 mm | 0.0630 | 1.600 |
| [M2×0.25](https://shopmath.org/threads/metric-fine/m2x0.25.md) | 0.250 | 0.0787 | 2.000 | 0.0724 | 1.838 | 0.0681 | 1.729 | 1.75 mm | 0.0689 | 1.750 |
| [M2.5×0.35](https://shopmath.org/threads/metric-fine/m2.5x0.35.md) | 0.350 | 0.0984 | 2.500 | 0.0895 | 2.273 | 0.0835 | 2.121 | 2.15 mm | 0.0847 | 2.150 |
| [M3×0.35](https://shopmath.org/threads/metric-fine/m3x0.35.md) | 0.350 | 0.1181 | 3.000 | 0.1092 | 2.773 | 0.1032 | 2.621 | 2.65 mm | 0.1043 | 2.650 |
| [M3.5×0.35](https://shopmath.org/threads/metric-fine/m3.5x0.35.md) | 0.350 | 0.1378 | 3.500 | 0.1289 | 3.273 | 0.1229 | 3.121 | 3.2 mm | 0.1260 | 3.200 |
| [M4×0.5](https://shopmath.org/threads/metric-fine/m4x0.5.md) | 0.500 | 0.1575 | 4.000 | 0.1447 | 3.675 | 0.1362 | 3.459 | 3.5 mm | 0.1378 | 3.500 |
| [M5×0.5](https://shopmath.org/threads/metric-fine/m5x0.5.md) | 0.500 | 0.1968 | 5.000 | 0.1841 | 4.675 | 0.1756 | 4.459 | 4.5 mm | 0.1772 | 4.500 |
| [M6×0.75](https://shopmath.org/threads/metric-fine/m6x0.75.md) | 0.750 | 0.2362 | 6.000 | 0.2170 | 5.513 | 0.2042 | 5.188 | 5.3 mm | 0.2087 | 5.300 |
| [M7×0.75](https://shopmath.org/threads/metric-fine/m7x0.75.md) | 0.750 | 0.2756 | 7.000 | 0.2564 | 6.513 | 0.2436 | 6.188 | 6.3 mm | 0.2480 | 6.300 |
| [M8×0.75](https://shopmath.org/threads/metric-fine/m8x0.75.md) | 0.750 | 0.3150 | 8.000 | 0.2958 | 7.513 | 0.2830 | 7.188 | 7.3 mm | 0.2874 | 7.300 |
| [M8×1](https://shopmath.org/threads/metric-fine/m8x1.md) | 1.000 | 0.3150 | 8.000 | 0.2894 | 7.350 | 0.2723 | 6.917 | 7 mm | 0.2756 | 7.000 |
| [M10×1](https://shopmath.org/threads/metric-fine/m10x1.md) | 1.000 | 0.3937 | 10.000 | 0.3681 | 9.350 | 0.3511 | 8.917 | 9 mm | 0.3543 | 9.000 |
| [M10×1.25](https://shopmath.org/threads/metric-fine/m10x1.25.md) | 1.250 | 0.3937 | 10.000 | 0.3617 | 9.188 | 0.3404 | 8.647 | 8.8 mm | 0.3465 | 8.800 |
| [M12×1.25](https://shopmath.org/threads/metric-fine/m12x1.25.md) | 1.250 | 0.4724 | 12.000 | 0.4405 | 11.188 | 0.4192 | 10.647 | 10.8 mm | 0.4252 | 10.800 |
| [M12×1.5](https://shopmath.org/threads/metric-fine/m12x1.5.md) | 1.500 | 0.4724 | 12.000 | 0.4341 | 11.026 | 0.4085 | 10.376 | 10.5 mm | 0.4134 | 10.500 |
| [M14×1.5](https://shopmath.org/threads/metric-fine/m14x1.5.md) | 1.500 | 0.5512 | 14.000 | 0.5128 | 13.026 | 0.4872 | 12.376 | 12.5 mm | 0.4921 | 12.500 |
| [M16×1.5](https://shopmath.org/threads/metric-fine/m16x1.5.md) | 1.500 | 0.6299 | 16.000 | 0.5916 | 15.026 | 0.5660 | 14.376 | 14.5 mm | 0.5709 | 14.500 |
| [M18×1.5](https://shopmath.org/threads/metric-fine/m18x1.5.md) | 1.500 | 0.7087 | 18.000 | 0.6703 | 17.026 | 0.6447 | 16.376 | 16.5 mm | 0.6496 | 16.500 |
| [M18×2](https://shopmath.org/threads/metric-fine/m18x2.md) | 2.000 | 0.7087 | 18.000 | 0.6575 | 16.701 | 0.6234 | 15.835 | 16 mm | 0.6299 | 16.000 |
| [M20×1.5](https://shopmath.org/threads/metric-fine/m20x1.5.md) | 1.500 | 0.7874 | 20.000 | 0.7491 | 19.026 | 0.7235 | 18.376 | 18.5 mm | 0.7284 | 18.500 |
| [M20×2](https://shopmath.org/threads/metric-fine/m20x2.md) | 2.000 | 0.7874 | 20.000 | 0.7363 | 18.701 | 0.7022 | 17.835 | 18 mm | 0.7087 | 18.000 |
| [M22×1.5](https://shopmath.org/threads/metric-fine/m22x1.5.md) | 1.500 | 0.8661 | 22.000 | 0.8278 | 21.026 | 0.8022 | 20.376 | 20.5 mm | 0.8071 | 20.500 |
| [M22×2](https://shopmath.org/threads/metric-fine/m22x2.md) | 2.000 | 0.8661 | 22.000 | 0.8150 | 20.701 | 0.7809 | 19.835 | 20 mm | 0.7874 | 20.000 |
| [M24×2](https://shopmath.org/threads/metric-fine/m24x2.md) | 2.000 | 0.9449 | 24.000 | 0.8937 | 22.701 | 0.8597 | 21.835 | 22 mm | 0.8661 | 22.000 |
| [M27×2](https://shopmath.org/threads/metric-fine/m27x2.md) | 2.000 | 1.0630 | 27.000 | 1.0118 | 25.701 | 0.9778 | 24.835 | 25 mm | 0.9842 | 25.000 |
| [M30×2](https://shopmath.org/threads/metric-fine/m30x2.md) | 2.000 | 1.1811 | 30.000 | 1.1300 | 28.701 | 1.0959 | 27.835 | 25 mm | 0.9842 | 25.000 |
| [M33×2](https://shopmath.org/threads/metric-fine/m33x2.md) | 2.000 | 1.2992 | 33.000 | 1.2481 | 31.701 | 1.2140 | 30.835 | 25 mm | 0.9842 | 25.000 |
| [M36×3](https://shopmath.org/threads/metric-fine/m36x3.md) | 3.000 | 1.4173 | 36.000 | 1.3406 | 34.051 | 1.2894 | 32.752 | 25 mm | 0.9842 | 25.000 |
| [M39×3](https://shopmath.org/threads/metric-fine/m39x3.md) | 3.000 | 1.5354 | 39.000 | 1.4587 | 37.051 | 1.4076 | 35.752 | 25 mm | 0.9842 | 25.000 |
| [M42×3](https://shopmath.org/threads/metric-fine/m42x3.md) | 3.000 | 1.6535 | 42.000 | 1.5768 | 40.051 | 1.5257 | 38.752 | 25 mm | 0.9842 | 25.000 |
| [M45×3](https://shopmath.org/threads/metric-fine/m45x3.md) | 3.000 | 1.7716 | 45.000 | 1.6949 | 43.051 | 1.6438 | 41.752 | 25 mm | 0.9842 | 25.000 |
| [M48×3](https://shopmath.org/threads/metric-fine/m48x3.md) | 3.000 | 1.8898 | 48.000 | 1.8130 | 46.051 | 1.7619 | 44.752 | 25 mm | 0.9842 | 25.000 |
| [M52×4](https://shopmath.org/threads/metric-fine/m52x4.md) | 4.000 | 2.0472 | 52.000 | 1.9450 | 49.402 | 1.8768 | 47.670 | 25 mm | 0.9842 | 25.000 |
| [M56×4](https://shopmath.org/threads/metric-fine/m56x4.md) | 4.000 | 2.2047 | 56.000 | 2.1024 | 53.402 | 2.0343 | 51.670 | 25 mm | 0.9842 | 25.000 |
| [M60×4](https://shopmath.org/threads/metric-fine/m60x4.md) | 4.000 | 2.3622 | 60.000 | 2.2599 | 57.402 | 2.1917 | 55.670 | 25 mm | 0.9842 | 25.000 |
| [M64×4](https://shopmath.org/threads/metric-fine/m64x4.md) | 4.000 | 2.5197 | 64.000 | 2.4174 | 61.402 | 2.3492 | 59.670 | 25 mm | 0.9842 | 25.000 |

_Basic dimensions are the theoretical values before a tolerance class is applied. Tap drills are for cut taps at the default engagement; per-size pages carry 50–85%._

## Sources and Method for the Metric fine Thread Chart

### Metric fine thread dimensions

- **Source**: ISO 68-1 basic profile and ISO 898-1 tensile stress area; verified in docs/research/data-sourcing.md §3.2; diameter/pitch pairs: ISO 261 / ISO 262 diameter-pitch pairs via Wikipedia (CC BY-SA 4.0); cross-checked against threadlib metric_thread.csv (BSD-3) and FreeCAD CAM metric-internal-6H.csv (LGPL-2.1+); clearance holes: ISO 273 (metric) and ASME B18.2.8 (inch) via FreeCAD FeatureHole.cpp (LGPL-2.1+), cross-checked against bd_warehouse clearance_hole_sizes.csv (Apache-2.0)
- **Method**: computed+compiled
- **Verified against**: threadlib metric_thread.csv (BSD-3-Clause) and FreeCAD CAM metric-internal-6H.csv (LGPL-2.1+), agreeing cell-for-cell — 215 checks passed at 0.001 mm

### Assumptions

- Tap drill figures are for cut taps at the default thread engagement; each size page carries the full 50–85% range.
- Dataset scope: EXCLUDED: ISO 965-1 tolerance-grade formulas (not located — data-sourcing.md open item 2), 6g external limits (single-sourced), form tap drills, M68-M100 (verified demand cliff at M64).

**Data last verified**: August 1, 2026

## Related pages

- Every thread series: [Screw thread reference](https://shopmath.org/threads.md)
- Cross-series chart: [Tap drill chart](https://shopmath.org/charts/tap-drill.md)
- Drill index: [Drill size chart](https://shopmath.org/charts/drill-sizes.md)

---

*Source: [ShopMath](https://shopmath.org/threads/metric-fine) — data verified August 1, 2026. Reference data; verify against the governing standard before manufacture.*