Counterbore Hole Size Chart for Shoulder Screws (JIS)
JIS counterbore hole size chart for shoulder screws, including pilot hole diameters for close, normal, and loose fits, counterbore diameters, and depths
Shoulder Screw Counterbore Hole Chart (JIS)
| Fastener Size (Thread) | Pilot Hole Diameter (mm) | Counterbore Diameter (mm) | Counterbore Depth (mm) | ||
|---|---|---|---|---|---|
| Close Fit | Normal Fit | Loose Fit | |||
| M5 | 7 | 7.4 | 8 | 13 | 4.5 |
| M6 | 8.4 | 9 | 10 | 17 | 5.5 |
| M8 | 10.5 | 11 | 12 | 19 | 7 |
| M10 | 14 | 14.5 | 15 | 23 | 9 |
| M12 | 17 | 17.5 | 18 | 27 | 11 |
| M16 | 21 | 22 | 24 | 35 | 14 |
| M20 | 27 | 29 | 31 | 42 | 16 |
About JIS Counterbore Hole Sizes for Shoulder Screws
This JIS counterbore hole size chart for shoulder screws provides standardized metric dimensions according to Japanese Industrial Standards (JIS). It lists recommended pilot hole diameters for close fit, normal fit, and loose fit, along with the corresponding counterbore diameters and counterbore depths in millimeters.
Using accurate JIS counterbore dimensions ensures proper shoulder screw seating, head clearance, and reliable mechanical performance in metric fastening applications. This reference is essential for engineers, machinists, and designers working with JIS shoulder screws, including:
- Mechanical and product design projects requiring JIS shoulder screws in metric systems.
- Machining, drilling, and fabrication processes that need precise pilot hole and counterbore preparation for standard shoulder screws.
- Assembly and quality control operations ensuring proper fit, alignment, and flush seating of shoulder screw heads.
Key Terms in the JIS Shoulder Screw Counterbore Chart
- Pilot Hole Diameter: The drilled hole diameter defining shoulder clearance, categorized for close, normal, or loose fit.
- Counterbore Diameter: The circular recess machined to allow the JIS shoulder screw head to sit flush or slightly below the surface.
- Counterbore Depth: The vertical depth of the recess matching the head height of the JIS shoulder screw.
- JIS Standard: The Japanese Industrial Standards specification defining dimensions, tolerances, and geometry for metric-series shoulder screws used in mechanical assemblies.
Referencing this JIS shoulder screw counterbore hole 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.