---
type: "drill"
designation: "#58"
series: "number"
series_name: "Number Drill Sizes"
diameter_in: 0.042
diameter_mm: 1.0668
standard: "ANSI/ASME B94.11M; BS 328"
verified: "August 1, 2026"
url: https://shopmath.org/drills/number/58
---

# #58 Drill Bit Size — 0.0420 in / 1.067 mm

A #58 drill bit is 0.0420 in (1.067 mm) in diameter. It belongs to the number series of standard twist drills.

- **Designation**: #58
- **Series**: Number
- **Diameter**: 0.0420 in (1.067 mm)

## #58 Drill Diameter

| Property | Value |
| --- | --- |
| Designation | #58 |
| Series | Number |
| Diameter (in) | 0.0420 |
| Diameter (mm) | 1.067 |

## #58 Drill Equivalents in the Other Size Series

The nearest standard drill to #58 in each of the other three series. Nothing here is an exact match unless the difference column reads 0.0000 in.

| Series | Nearest drill | Diameter (in) | Diameter (mm) | Difference |
| --- | --- | --- | --- | --- |
| Letter | [A](https://shopmath.org/drills/letter/a.md) | 0.2340 | 5.944 | +0.1920 in |
| Fractional | [3/64](https://shopmath.org/drills/fractional/3-64.md) | 0.0469 | 1.191 | +0.0049 in |
| Metric | [1.05 mm](https://shopmath.org/drills/metric/1-05mm.md) | 0.0413 | 1.050 | -0.0007 in |

## Sources and Method for the #58 Drill Size

### Drill index

- **Source**: Number/letter: bd_warehouse drill_sizes.csv (Apache-2.0) cross-checked against Wikipedia Drill bit sizes (CC BY-SA 4.0). Fractional: computed 1/64 in steps per ANSI B94.11M. Metric: computed BS 328 increment pattern.
- **Method**: compiled
- **Verified against**: Wikipedia Drill bit sizes (CC BY-SA 4.0); 31/31 checks passed

### Assumptions

- Drill diameters are nominal. A worn or run-out drill cuts oversize; measure the hole, not the shank, when the fit matters.
- Dataset scope: Number sizes #61-#80 are stored but tagged demandTier 'extended' — query-space-map.md Appendix A found the tail thinning in the 60s. Sizes below #80 and metric sizes above 25.0 mm excluded.

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

## Common Questions About the #58 Drill Bit

### What size is a #58 drill bit size?

A #58 drill bit is 0.0420 in (1.067 mm) in diameter.

### What is the metric equivalent of a #58 drill bit?

The closest metric drill to #58 (0.0420 in (1.067 mm)) is 1.05 mm at 0.0413 in (1.050 mm) — a difference of 0.0007 in.

### What fraction is a #58 drill bit?

#58 is 0.0420 in (1.067 mm), which is not itself a fractional size. The closest fractional drill is 3/64 at 0.0469 in (1.191 mm).

## Related pages

- Next size down (any series): [1.05 mm](https://shopmath.org/drills/metric/1-05mm.md) — 0.0413 in (1.050 mm)
- Next size up (any series): [#57](https://shopmath.org/drills/number/57.md) — 0.0430 in (1.092 mm)
- Previous in the number series: [#57](https://shopmath.org/drills/number/57.md)
- Next in the number series: [#59](https://shopmath.org/drills/number/59.md)
- All number sizes: [Number drill sizes](https://shopmath.org/drills/number.md)
- All drill sizes: [Drill bit size reference](https://shopmath.org/drills.md)
- Complete index by diameter: [Drill size chart](https://shopmath.org/charts/drill-sizes.md)
- Tap drills by thread: [Tap drill chart](https://shopmath.org/charts/tap-drill.md)

---

*Source: [ShopMath](https://shopmath.org/drills/number/58) — data verified August 1, 2026. Reference data; verify against the governing standard before manufacture.*