ISO 262 is an international standard that defines a subset of metric thread sizes from ISO 261. It specifies the most commonly used sizes, optimizing manufacturing efficiency and reducing unnecessary variations in thread dimensions.
The goal of ISO 262 is to simplify production, ensure compatibility, and minimize costs by standardizing thread sizes that are widely used across industries.
ISO 262 is closely related to:
- ISO 68-1 (Thread Profile Definition)
- ISO 261 (Standard Metric Thread Sizes)
- ISO 724 (Basic Thread Dimensions)
Technical Details
ISO 262 selects specific thread sizes and pitches from ISO 261, ensuring:
✅ Standardization in global manufacturing
✅ Interchangeability of threaded fasteners
✅ Reduced inventory complexity
ISO 262 covers both coarse and fine-pitch metric threads.
ISO 262 Preferred Thread Size Tables
Preferred Metric Thread Sizes (Coarse Pitch)
| Nominal Diameter (M) | Pitch (P) (mm) | Major Diameter (D/d) (mm) | Minor Diameter (D₁/d₁) (mm) | Tap Drill Size (mm) |
|---|---|---|---|---|
| M1 | 0.25 | 1.00 | 0.75 | 0.8 |
| M1.6 | 0.35 | 1.60 | 1.25 | 1.3 |
| M2 | 0.40 | 2.00 | 1.60 | 1.7 |
| M2.5 | 0.45 | 2.50 | 2.05 | 2.1 |
| M3 | 0.50 | 3.00 | 2.40 | 2.5 |
| M4 | 0.70 | 4.00 | 3.30 | 3.4 |
| M5 | 0.80 | 5.00 | 4.20 | 4.3 |
| M6 | 1.00 | 6.00 | 5.00 | 5.2 |
| M8 | 1.25 | 8.00 | 6.75 | 6.8 |
| M10 | 1.50 | 10.00 | 8.50 | 8.8 |
| M12 | 1.75 | 12.00 | 10.20 | 10.5 |
| M16 | 2.00 | 16.00 | 13.90 | 14.0 |
| M20 | 2.50 | 20.00 | 17.30 | 17.5 |
| M24 | 3.00 | 24.00 | 20.90 | 21.0 |
🔹 Note: These coarse threads are the most commonly used sizes in ISO 262.
Preferred Fine Pitch Metric Threads (ISO 262)
| Nominal Diameter (M) | Fine Pitch (mm) | Major Diameter (mm) | Minor Diameter (mm) | Tap Drill Size (mm) |
|---|---|---|---|---|
| M8 × 1 | 1.00 | 8.00 | 7.00 | 7.1 |
| M10 × 1.25 | 1.25 | 10.00 | 8.75 | 8.8 |
| M12 × 1.5 | 1.50 | 12.00 | 10.50 | 10.8 |
| M16 × 1.5 | 1.50 | 16.00 | 14.50 | 14.8 |
| M20 × 1.5 | 1.50 | 20.00 | 18.50 | 18.8 |
🔹 Note: Fine-pitch threads are used in high-precision applications requiring better resistance to loosening.
Applications of ISO 262 Preferred Thread Sizes
ISO 262 is applied in industries requiring standardized fasteners, including:
- Automotive (engine components, wheel bolts)
- Aerospace (aircraft fasteners, precision assemblies)
- Machinery & Manufacturing (threaded rods, industrial machinery)
- Construction (structural bolts, anchor fasteners)
The standardization improves compatibility and reduces manufacturing costs by using only the most widely accepted thread sizes.
Related Metric Thread Standards
After reviewing ISO 262, you may also find these related standards useful:
- ISO 68-1 – Metric Thread Profile (Defines the fundamental shape of metric threads.)
- ISO 261 – Standard Metric Thread Sizes (Covers the full range of standard metric thread sizes.)
- ISO 724 – Basic Dimensions of Metric Threads (Defines the fundamental dimensions for metric screw threads.)
- ISO 965 – Metric Thread Tolerances (Specifies tolerances for external and internal metric threads.)
- ISO 1502 – Thread Gauges for Metric Threads (Provides details on thread inspection using gauges.)
These links allow users to navigate easily between related standards.
Important Notice on Standards Validity
This information is for reference purposes only. Users should consult official sources and updated standards to ensure compliance with current regulations.
The validity of standards may change over time, so it is recommended to verify them through recognized engineering and standardization organizations (ISO, DIN, ANSI, ASME, etc.).
Check with relevant standardization bodies in your region to confirm whether a specific standard is still valid and applicable. Regulations and industry requirements may vary based on region and application.