Counterbore Hole Size Chart for Cheese Head Fasteners (JIS)
All dimensions are in millimetres
Cheese Head Fastener Chart (JIS)
| Fastener Size | Pilot Hole Diameter (mm) | Counterbore Diameter (mm) | Counterbore Depth (mm) | ||
|---|---|---|---|---|---|
| Close Fit Grade 1 | Normal Fit Grade 2 | Loose Fit Grade 3 | |||
| M1.6 | 1.7 | 1.8 | 2 | 3.5 | 1.7 |
| M2 | 2.2 | 2.4 | 2.6 | 4.4 | 1.9 |
| M2.5 | 2.7 | 2.9 | 3.1 | 5.5 | 2.3 |
| M3 | 3.2 | 3.4 | 3.6 | 6.5 | 2.5 |
| M4 | 4.3 | 4.5 | 4.8 | 8 | 3.1 |
| M5 | 5.3 | 5.5 | 5.8 | 10 | 4.1 |
| M6 | 6.4 | 6.6 | 7 | 11 | 4.7 |
| M8 | 8.4 | 9 | 10 | 15 | 5.8 |
| M10 | 10.5 | 11 | 12 | 18 | 6.8 |
About JIS Counterbore Hole Sizes for Cheese Head Fasteners
This JIS counterbore hole size chart provides engineers, machinists, and designers with standardized data for cheese head fasteners according to the Japanese Industrial Standards (JIS). It includes pilot hole diameters for Grade 1 (close fit), Grade 2 (normal fit), and Grade 3 (loose fit), along with corresponding counterbore diameters and counterbore depths in millimetres.
Following standardized JIS counterbore dimensions ensures precise screw seating, proper alignment between components, and consistent fit quality in mechanical assemblies. This chart is particularly useful for:
- Mechanical and design engineers working with JIS-standard fasteners in machinery or tooling design.
- Machinists and technicians drilling pilot holes and counterbores for accurate cheese head screw installation.
- Manufacturers producing components that comply with Japanese Industrial Standards for interchangeability and precision.
Key Terms in the JIS Counterbore Chart
- Pilot Hole Diameter (Grades 1–3): The drilled guide hole that determines the fit precision between the fastener and the component.
- Counterbore Diameter: The circular recess machined to allow the cheese head screw to sit flush or slightly below the surface.
- Counterbore Depth: The measured vertical depth of the recess, matching the screw head height for proper seating.
- JIS Standard: The Japanese Industrial Standard defining specifications, tolerances, and fit classes for fasteners and mechanical components.
Consulting the JIS cheese head fastener counterbore hole size chart helps ensure dimensional accuracy, reliable screw seating, and compliance with Japanese engineering standards. These specifications are essential for high-precision manufacturing, equipment assembly, and mechanical design applications requiring JIS-certified fasteners.