Counterbore Hole Size Chart for Cheese Head Fasteners (ISO)
ISO counterbore hole size chart for cheese head fasteners, including pilot hole diameters (H12, H13, H14), counterbore diameters, and depths in millimetres
Cheese Head Fastener Chart (ISO)
| 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 | 3.5 | 1.5 |
| M2 | 2.2 | 2.4 | 2.6 | 4.4 | 1.8 |
| M2.5 | 2.7 | 2.9 | 3.1 | 5.5 | 2.2 |
| M3 | 3.2 | 3.4 | 3.6 | 6.5 | 2.4 |
| M4 | 4.3 | 4.5 | 4.8 | 8 | 3 |
| M5 | 5.3 | 5.5 | 5.8 | 10 | 3.7 |
| M6 | 6.4 | 6.6 | 7 | 11 | 4.5 |
| M8 | 8.4 | 9 | 10 | 15 | 5.6 |
| M10 | 10.5 | 11 | 12 | 18 | 6.6 |
About ISO Counterbore Hole Sizes for Cheese Head Fasteners
This ISO counterbore hole size chart provides engineers, machinists, and designers with standardized dimensional data for cheese head fasteners according to ISO standards. It includes pilot hole diameters (H12, H13, H14), counterbore diameters, and counterbore depths—all expressed in millimetres—to ensure accurate screw seating and reliable mechanical assembly.
Using standardized ISO counterbore dimensions ensures proper alignment, repeatability, and interchangeability in design and manufacturing. This information is particularly useful for:
- Mechanical and design engineers creating assemblies with ISO-standard cheese head fasteners.
- Machinists drilling pilot holes and counterbores that meet precise fit tolerances.
- Manufacturers ensuring compliance with international fastener standards for quality and compatibility.
Key Terms in the ISO Counterbore Chart
- Pilot Hole Diameter (H12, H13, H14): The initial drilled guide hole for the screw, with specific tolerance grades defining the fit precision.
- Counterbore Diameter: The cylindrical recess machined to allow the cheese head screw to sit flush or slightly below the surface.
- Counterbore Depth: The vertical distance of the recess that accommodates the screw head height.
- ISO Standard: The International Organization for Standardization standard defining dimensions, tolerances, and mechanical properties for fasteners worldwide.
Consulting the ISO cheese head fastener counterbore hole size chart ensures consistent fastener fit, dimensional accuracy, and adherence to international engineering standards. These dimensions are vital for precision machining, product design, and high-quality mechanical assembly.