Drilling & Fabrication
24 mm drill bit size
A 24 mm nominal drill diameter is 0.94488 inches. A nearest fractional drill is an approximation, not the same diameter.
Maintained by mmtoinches.im · Updated
NIST describes the standard inch as exactly equivalent to 25.4 mm
. NIST length definition. Method and limitations.
Quick reference for 24 mm drill bits: rounded decimal inches and nearest fractional equivalents for common workshop denominators. Includes practical guidance and related charts.
Nearest fractional sizes
- 1/16 increments: 15/16" (approx)
- 1/32 increments: 15/16" (near‑match)
- 1/64 increments: 15/16" (closest among common denominators)
Use fractional equivalents when tooling or documentation requires imperial sizes. Always check tolerance demands before substituting fractional bits.
Practical guidance
- Select a drill designed for the material and secure the workpiece.
- Choose cutting speed and feed from the tool manufacturer guidance; diameter alone does not determine RPM.
- Use the appropriate backing, lubrication, and breakthrough procedure for the material and tool.
- Verify the finished hole with an instrument suitable for the required tolerance.
Illustrative tap-drill estimates
These metric coarse-pitch examples illustrate the estimate major diameter − pitch for a cutting tap. The difference column is this bit diameter minus the estimate, not an approval or fit class. The formula is not suitable for selecting a forming-tap drill. For actual tap drills and clearance holes, follow the drawing and manufacturer recommendations.
| Thread | Pitch (mm) | Major diameter (mm) | Estimated cutting-tap drill (mm) | Bit − estimate (mm) |
|---|---|---|---|---|
| M12 | 1.75 | 12.00 | 10.25 | +13.75 |
| M11 | 1.50 | 11.00 | 9.50 | +14.50 |
| M10 | 1.50 | 10.00 | 8.50 | +15.50 |
| M9 | 1.25 | 9.00 | 7.75 | +16.25 |
| M8 | 1.25 | 8.00 | 6.75 | +17.25 |
| M7 | 1.00 | 7.00 | 6.00 | +18.00 |
| M6 | 1.00 | 6.00 | 5.00 | +19.00 |
| M5 | 0.80 | 5.00 | 4.20 | +19.80 |
FAQ
What is a 24 mm drill bit in inches?
24 mm equals 0.94488 inches. Rounded fractional equivalents are 15/16" at 1/32 inch and 15/16" at 1/64 inch. These are different nominal diameters, not interchangeable drill recommendations.
What is 24 mm used for?
The nominal diameter identifies a 24 mm hole-size reference. Whether it is suitable for a pilot, clearance, or tapped hole depends on the fastener, required tolerance, material, and drill design. Use the drawing and tool manufacturer recommendations rather than selecting an application from diameter alone.
How do I avoid tear‑out with a 24 mm bit?
Secure the workpiece and follow the drill manufacturer guidance for the material, cutting speed, feed, and breakthrough. An appropriate backing piece may reduce breakout in suitable materials. Do not apply one RPM or lubrication rule to every drill and material.
Need more tooling references?
Compare full drill bit tables, review tap drill recommendations, or switch to the mm→in calculator for arbitrary sizes. Printable charts are available.
Sources and calculation notes
A 24 mm nominal drill diameter is 0.94488 inches. A nearest fractional drill is an approximation, not the same diameter.
Method: Divide millimeters by 25.4 to obtain inches. The factor is exact; displayed decimal values are rounded. Fractional inches are rounded to the selected denominator.
Scope: A unit conversion does not establish a manufacturing tolerance or guarantee that similarly sized parts fit. Keep the original measurement and its uncertainty.
Content maintained by mmtoinches.im. Updated and reference notes reviewed . How we calculate and present measurements. Sources support the stated definitions; examples and calculators are not certification of a product or compliance with a standard.