Counterbore Hole Size Chart for Pan Head Screws (JIS)
JIS counterbore hole size chart for pan head screws, including pilot hole diameters for close, normal, and loose fits, counterbore diameters, and depths (millimeters)
Pan Head Screw Counterbore Hole Chart (JIS)
| Fastener Size | Pilot Hole Diameter (mm) | Counterbore Diameter (mm) | Counterbore Depth (mm) | ||
|---|---|---|---|---|---|
| Close Fit | Normal Fit | Loose Fit | |||
| M1.6 | 1.7 | 1.8 | 2 | 3.5 | 1.5 |
| M2 | 2.2 | 2.4 | 2.6 | 5 | 2.1 |
| M2.5 | 2.7 | 2.9 | 3.1 | 6 | 2.6 |
| M3 | 3.2 | 3.4 | 3.6 | 7 | 2.9 |
| M3.5 | 3.7 | 3.9 | 4.2 | 8 | 3.1 |
| M4 | 4.3 | 4.5 | 4.8 | 9 | 3.6 |
| M5 | 5.3 | 5.5 | 5.8 | 11 | 4.5 |
| M6 | 6.4 | 6.6 | 7 | 13 | 5.4 |
| M8 | 8.4 | 9 | 10 | 18 | 6.8 |
| M10 | 10.5 | 11 | 12 | 24 | 8.3 |
About JIS Counterbore Hole Sizes for Pan Head Screws
This JIS counterbore hole size chart for pan head screws provides standardized metric dimensions according to the Japanese Industrial Standards (JIS). It includes recommended pilot hole diameters for close fit, normal fit, and loose fit, along with the corresponding counterbore diameters and counterbore depths in millimeters.
Accurate JIS counterbore dimensions ensure proper screw seating, head clearance, and reliable mechanical performance in metric fastening applications. This reference is essential for engineers, machinists, and designers working with JIS pan head screws, including:
- Mechanical and product design projects requiring JIS pan head machine screws in metric systems.
- Machining, drilling, and fabrication processes that need precise pilot hole and counterbore preparation for standard fasteners.
- Assembly and quality control operations ensuring proper fit, alignment, and flush seating of screw heads.
Key Terms in the JIS Counterbore Hole Chart
- Pilot Hole Diameter: The drilled hole diameter defining screw shank clearance, categorized for close, normal, or loose fit.
- Counterbore Diameter: The circular recess machined to allow the JIS pan head screw to sit flush or slightly below the surface.
- Counterbore Depth: The vertical depth of the recess matching the head height of the JIS pan head screw.
- JIS Standard: The Japanese Industrial Standards specification defining dimensions and tolerances for metric-series pan head screws used in mechanical assemblies.
Consulting this JIS pan head screw counterbore hole size 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.