Number drill · #53
#53 Drill Bit Size — Decimal Inch, Millimetre and Tap Sizes
https://shopmath.org/drills/number/53 · data verified August 1, 2026
A #53 drill bit is 0.0595 in (1.511 mm) in diameter. It is the tap drill for #1-72 UNF at 75% thread engagement with a cut tap, where it leaves 74.8% thread. The nearest fractional size is 1/16" at 0.0625 in. Diameters are nominal.
- Series
- Number
- Designation
- #53
- Inch
- 0.0595
- mm
- 1.511
- Standard
- ANSI/ASME B94.11M
Number Drill · #53 · nominal diameter
0.0595 in
- Millimetre
- 1.511mm
- Taps
- #1-72 UNF
Nominal diameter. As a tap drill it leaves 74.8% thread in #1-72 UNF with a cut tap.
#53 Drill Bit Size in Inches and Millimetres
The nominal diameter of a #53 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.
| Property | Value |
|---|---|
| Diameter, decimal inch | 0.0595 in |
| Diameter, millimetre | 1.511 mm |
| Cross-sectional area | 0.00278 in² |
1 in = 25.4 mm exactly, so the two columns are the same value in different units, not two measurements.
Threads a #53 Drill Bit Taps
Every thread in this reference whose tap drill is the #53 drill bit, and the thread engagement it leaves. The engagement asked for and the engagement the drill actually produces are different numbers — that gap is why both columns are here.
| Thread | Series | Thread % asked for | Thread % this drill leaves |
|---|---|---|---|
| #1-72 UNF | Unified Fine (UNF) | 75%default | 74.8 |
| #1-64 UNC | Unified Coarse (UNC) | 75%default | 66.5 |
| #1-72 UNF | Unified Fine (UNF) | 70% | 74.8 |
| #1-72 UNF | Unified Fine (UNF) | 80% | 74.8 |
| #1-72 UNF | Unified Fine (UNF) | 85% | 74.8 |
| #1-64 UNC | Unified Coarse (UNC) | 60% | 66.5 |
| #1-64 UNC | Unified Coarse (UNC) | 65% | 66.5 |
| #1-64 UNC | Unified Coarse (UNC) | 70% | 66.5 |
Values are for cut taps. Rows marked default are the shop-default engagement for that thread.
#53 Drill Bit Equivalents in Every Other Drill Series
The closest size to the #53 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.
| Property | Property | Diameter | Property | |
|---|---|---|---|---|
| Drill | Series | in | mm | Difference, in |
| A | Letter | 0.2340 | 5.944 | +0.1745 |
| 1/16" | Fractional | 0.0625 | 1.587 | +0.0030 |
| 1.5 mm | Metric | 0.0591 | 1.500 | −0.0004 |
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 #53 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.
Sources and Method for the #53 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.
- Tap drill usagecomputed+compiled
bd_warehouse drill_sizes.csv (Apache-2.0) + Wikipedia Drill bit sizes (CC BY-SA 4.0); fractional and metric computed from ANSI B94.11M / BS 328 increment patterns
Verified against drills: 31 checks passed across 1 harness(es)
Part computed from the standard's formulas, part compiled from agreeing public sources.
- 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.
- Tap drill usage assumes cut taps. #1-72 UNF at 75% requested engagement is what this drill is normally bought for.
- 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 to Cite This #53 Drill Bit Reference
Citation
ShopMath. "#53 Drill Bit Size — Decimal Inch, Millimetre and Tap Sizes." ShopMath, verified August 1, 2026, https://shopmath.org/drills/number/53
BibTeX
@misc{shopmath-drills-number-53,
title = {#53 Drill Bit Size — Decimal Inch, Millimetre and Tap Sizes},
author = {{ShopMath}},
year = {2026},
howpublished = {\url{https://shopmath.org/drills/number/53}},
note = {Data verified 2026-08-01}
}Permanent URL
https://shopmath.org/drills/number/53
Common Questions About the #53 Drill Bit
What size is a #53 drill bit?
- A #53 drill bit is 0.0595 in in diameter, which is 1.511 mm.
What thread does a #53 drill bit tap?
- A #53 drill bit is the tap drill for #1-72 UNF at 75% requested thread engagement, where it leaves 74.8% thread with a cut tap. It is the default tap drill for 2 threads in this reference.
What is the metric equivalent of a #53 drill bit?
- The closest metric drill to a #53 drill bit (1.511 mm) is 1.5 mm, which is 1.500 mm — 0.0004 in smaller.
What fraction is a #53 drill bit closest to?
- A #53 drill bit (0.0595 in) sits closest to the 1/16" fractional drill at 0.0625 in, a difference of 0.0030 in.
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