ISO 10642 is the international standard for Hexagon Socket Countersunk Head Screws. While technically defined as a machine screw, this fastener is frequently utilized as a countersunk bolt in high-precision structural assemblies where a flush surface finish is mandatory.

As the global successor to the older DIN 7991 standard, ISO 10642 specifies the tolerances and dimensions for metric series fasteners from M3 up to M20. These components are designed to distribute load through a 90-degree conical head, allowing the bolt to sit perfectly flat within the material, making it ideal for moving mechanical parts or aesthetic architectural panels.

The technical focus of ISO 10642 is Flush Fastening and Aerodynamic Integrity. Due to the countersunk head geometry, the load-bearing capacity of this screw is approximately 80% of a standard cylinder head bolt of the same property class. Therefore, ISO 10642 is primarily produced in high-tensile Property Classes 8.8, 10.9, and 12.9 to ensure sufficient clamping force despite the reduced head volume.