ISO 4014 is the cornerstone international standard for hexagon head bolts with a Partial Thread. Designed for high-performance structural applications, this standard specifies the characteristics of bolts with thread sizes from M1.6 up to M64, ensuring precision, strength, and global interchangeability.

The presence of an unthreaded shank (grip length) in ISO 4014 provides superior shear resistance compared to fully threaded screws, making it the preferred choice for heavy machinery, steel construction, and automotive chassis where structural integrity is paramount.

The mechanical advantage of ISO 4014 lies in its Shank Geometry. By aligning the solid, unthreaded portion of the bolt within the shear plane of a joint, the assembly benefits from the full cross-sectional area of the material, significantly reducing stress concentration compared to threaded sections. This standard is divided into Product Grade A (for sizes up to M24 and lengths ≤ 10d or 150mm) and Product Grade B (for larger sizes or longer lengths).