Counterbore Hole Size Chart for Socket Head Screws (JIS)
JIS counterbore hole size chart for socket head screws, including pilot hole diameters for close, normal, and loose fits, counterbore diameters, and depths (millimeters)
Socket Head Screw Counterbore Hole Chart (JIS)
| Fastener Size | Pilot Hole Diameter (mm) | Counterbore Diameter (mm) | Counterbore Depth (mm) | ||
|---|---|---|---|---|---|
| Close Fit (H12) | Normal Fit (H13) | Loose Fit (H14) | |||
| M1.6 | 1.7 | 1.8 | 2.0 | 3.5 | 1.8 |
| M2 | 2.2 | 2.4 | 2.6 | 4.4 | 2.2 |
| M2.5 | 2.7 | 2.9 | 3.1 | 5.5 | 3.0 |
| M3 | 3.2 | 3.4 | 3.6 | 6.5 | 3.5 |
| M4 | 4.3 | 4.5 | 4.8 | 8.0 | 4.8 |
| M5 | 5.3 | 5.5 | 5.8 | 10.0 | 5.8 |
| M6 | 6.4 | 6.6 | 7.0 | 11.0 | 6.8 |
| M8 | 8.4 | 9.0 | 10.0 | 15.0 | 8.8 |
| M10 | 10.5 | 11.0 | 12.0 | 18.0 | 10.8 |
| M12 | 13.0 | 13.5 | 14.5 | 20.0 | 12.8 |
| M16 | 17.0 | 17.5 | 18.5 | 26.0 | 16.8 |
| M20 | 21.0 | 22.0 | 24.0 | 33.0 | 21.0 |
| M24 | 25.0 | 26.0 | 28.0 | 40.0 | 25.0 |
| M30 | 31.0 | 33.0 | 35.0 | 50.0 | 31.0 |
| M36 | 37.0 | 39.0 | 42.0 | 58.0 | 37.0 |
| M42 | 43.0 | 45.0 | 48.0 | 69.0 | 43.0 |
| M48 | 50.0 | 52.0 | 56.0 | 78.0 | 49.0 |
About ISO 4762 Counterbore Hole Sizes for Socket Head Screws
This ISO 4762 counterbore hole size chart for socket head screws provides standardized dimensions in millimeters according to the ISO 4762 standard. It lists recommended pilot hole diameters for close fit (H12), normal fit (H13), and loose fit (H14), along with the corresponding counterbore diameters and counterbore depths in millimeters.
Using accurate ISO 4762 counterbore dimensions ensures proper screw seating, head clearance, and reliable mechanical performance in metric fastening applications. This reference is essential for engineers, machinists, and designers working with ISO 4762 socket head screws, including:
- Mechanical and product design projects requiring ISO 4762 socket head screws in metric systems.
- Machining, drilling, and fabrication processes that need precise pilot hole and counterbore preparation for standard socket head screws.
- Assembly and quality control operations ensuring proper fit, alignment, and flush seating of socket head screw heads.
Key Terms in the ISO 4762 Socket Head Screw Counterbore Chart
- Pilot Hole Diameter (H12 / H13 / H14): The drilled hole diameter defining screw clearance, categorized by tolerance grade for close, normal, or loose fit.
- Counterbore Diameter: The circular recess machined to allow the ISO 4762 socket head screw to sit flush or slightly below the surface.
- Counterbore Depth: The vertical depth of the recess matching the head height of the ISO 4762 socket head screw.
- ISO 4762 Standard: The International Organization for Standardization (ISO) 4762 specification defining dimensions, tolerances, and geometry for metric-series socket head screws used in mechanical assemblies.
Referencing this ISO 4762 socket head screw counterbore chart ensures consistent part design, precise manufacturing, and compliance with international metric fastener standards. Proper use of these dimensions improves assembly quality, reduces machining errors, and enhances the reliability of mechanical systems.