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Metric drill · 23.5 mm

23.5 mm Drill Bit Size — Decimal Inch, Millimetre and Tap Sizes

A 23.5 mm drill bit is 0.9252 in (23.500 mm) in diameter. The nearest fractional size is 59/64" at 0.9219 in. Diameters are nominal.

Series
Metric
Designation
23.5 mm
Inch
0.9252
mm
23.500
Standard
ANSI/ASME B94.11M

Metric Drill · 23.5 mm · nominal diameter

0.9252 in

Millimetre
23.500mm

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

23.5 mm Drill Bit Size in Inches and Millimetres

The nominal diameter of a 23.5 mm 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.

23.5 mm drill bit — decimal inch and millimetre diameter
PropertyValue
Diameter, decimal inch0.9252 in
Diameter, millimetre23.500 mm
Cross-sectional area0.67229 in²

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

23.5 mm Drill Bit Equivalents in Every Other Drill Series

The closest size to the 23.5 mm 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 23.5 mm drill bit
PropertyPropertyDiameterProperty
DrillSeriesinmmDifference, in
#1Number0.22805.791−0.6972
ZLetter0.413010.490−0.5122
59/64"Fractional0.921923.416−0.0033

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 23.5 mm 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 23.5 mm drill bit, by diameter
PropertyPropertyDiameter
DrillSeriesinmm
23.25 mmMetric0.915423.250
59/64"Fractional0.921923.416
23.5 mmMetric0.925223.500
23.75 mmMetric0.935023.750
15/16"Fractional0.937523.813

Sources and Method for the 23.5 mm Drill Bit Size

Drill diametercomputed

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

Computed from the standard's formulas, then checked against published tables.

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 23.5 mm Drill Bit Reference

Citation

ShopMath. "23.5 mm Drill Bit Size — Decimal Inch, Millimetre and Tap Sizes." ShopMath, verified August 1, 2026, https://shopmath.org/drills/metric/23-5mm

BibTeX

@misc{shopmath-drills-metric-23-5mm,
  title        = {23.5 mm Drill Bit Size — Decimal Inch, Millimetre and Tap Sizes},
  author       = {{ShopMath}},
  year         = {2026},
  howpublished = {\url{https://shopmath.org/drills/metric/23-5mm}},
  note         = {Data verified 2026-08-01}
}

Permanent URL

https://shopmath.org/drills/metric/23-5mm

Common Questions About the 23.5 mm Drill Bit

What size is a 23.5 mm drill bit?

A 23.5 mm drill bit is 0.9252 in in diameter, which is 23.500 mm.

What fraction is a 23.5 mm drill bit closest to?

A 23.5 mm drill bit (0.9252 in) sits closest to the 59/64" fractional drill at 0.9219 in, a difference of 0.0033 in.

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