What size is a #59 drill bit?

A #59 drill bit is 0.0410 in in diameter, which is 1.041 mm.

What is the metric equivalent of a #59 drill bit?

The closest metric drill to a #59 drill bit (1.041 mm) is 1.05 mm, which is 1.050 mm — 0.0003 in larger.

What fraction is a #59 drill bit closest to?

A #59 drill bit (0.0410 in) sits closest to the 3/64" fractional drill at 0.0469 in, a difference of 0.0059 in.

Number drill · #59

#59 Drill Bit Size — Decimal Inch, Millimetre and Tap Sizes

https://shopmath.org/drills/number/59 · data verified August 1, 2026

A #59 drill bit is 0.0410 in (1.041 mm) in diameter. The nearest fractional size is 3/64" at 0.0469 in. Diameters are nominal.

Series: Number
Designation: #59
Inch: 0.0410
mm: 1.041
Standard: ANSI/ASME B94.11M

Number Drill · #59 · nominal diameter

0.0410 in

Millimetre: 1.041mm

Nominal diameter. A worn or run-out drill cuts oversize, which leaves less thread in a tapped hole than the table says.

#59 Drill Bit Size in Inches and Millimetres

The nominal diameter of a #59 drill bit. Drill sizes are nominal — a worn drill, run-out or a soft material that closes in behind the cut all move the finished hole.

#59 drill bit — decimal inch and millimetre diameter
Property	Value
Diameter, decimal inch	0.0410 in
Diameter, millimetre	1.041 mm
Cross-sectional area	0.00132 in²

1 in = 25.4 mm exactly, so the two columns are the same value in different units, not two measurements.

#59 Drill Bit Equivalents in Every Other Drill Series

The closest size to the #59 drill bit in each of the other three indexes, with the difference in inches. None of them is the same drill — check the difference before substituting one into a tapped hole.

Nearest number, letter, fractional and metric equivalents to a #59 drill bit
Property	Property	Diameter		Property
Drill	Series	in	mm	Difference, in
A	Letter	0.2340	5.944	+0.1930
3/64"	Fractional	0.0469	1.191	+0.0059
1.05 mm	Metric	0.0413	1.050	+0.0003

A positive difference means the equivalent drill is larger, which leaves less thread in a tapped hole. Sizes without a link are stored for the nearest-drill calculation but do not carry their own page.

Drill Sizes Either Side of the #59 Drill Bit

Ordered by diameter across all four indexes, so the next size up may be a letter, a fraction or a metric drill rather than the next one in this series.

Standard drill sizes adjacent to a #59 drill bit, by diameter
Property	Property	Diameter
Drill	Series	in	mm
1 mm	Metric	0.0394	1.000
#60	Number	0.0400	1.016
#59	Number	0.0410	1.041
1.05 mm	Metric	0.0413	1.050
#58	Number	0.0420	1.067

Sources and Method for the #59 Drill Bit Size

Drill diametercompiled

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.

Verified against Wikipedia Drill bit sizes (CC BY-SA 4.0); 31/31 checks passed

Compiled from independent public sources that agree cell-for-cell.

Assumptions

Diameters are nominal. Drill manufacturing tolerance, wear and run-out all cut oversize, and every one of those moves a tapped hole toward less thread than the table says.
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

How this data is built and checked →

How to Cite This #59 Drill Bit Reference

Citation

ShopMath. "#59 Drill Bit Size — Decimal Inch, Millimetre and Tap Sizes." ShopMath, verified August 1, 2026, https://shopmath.org/drills/number/59

BibTeX

@misc{shopmath-drills-number-59,
  title        = {#59 Drill Bit Size — Decimal Inch, Millimetre and Tap Sizes},
  author       = {{ShopMath}},
  year         = {2026},
  howpublished = {\url{https://shopmath.org/drills/number/59}},
  note         = {Data verified 2026-08-01}
}

Permanent URL

https://shopmath.org/drills/number/59

Common Questions About the #59 Drill Bit

What size is a #59 drill bit?: A #59 drill bit is 0.0410 in in diameter, which is 1.041 mm.
What is the metric equivalent of a #59 drill bit?: The closest metric drill to a #59 drill bit (1.041 mm) is 1.05 mm, which is 1.050 mm — 0.0003 in larger.
What fraction is a #59 drill bit closest to?: A #59 drill bit (0.0410 in) sits closest to the 3/64" fractional drill at 0.0469 in, a difference of 0.0059 in.

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