Knurled Hex Socket Head Cap Metal Screw With A Hole M8 M9 M10 Black Zinc Plated Galvanized Carbon Steel

Knurled Hex Socket Head Cap Metal Screw With A Hole M8 M9 M10 Black Zinc Plated Galvanized Carbon Steel 

This hex socket head cap screw combines knurling under the head and a transverse hole through the head. The knurling aids hand starting, while the hole allows safety wire or cotter pin insertion for positive mechanical locking against loosening. Material: carbon steel with black zinc plating (black passivated zinc). Strength class typically 8.8 or 10.9. Sizes M8, M9, M10 suit medium-duty industrial connections. The drilled hole design is essential in high-vibration environments such as engine peripherals, railway equipment, and mining machinery. Black zinc provides a uniform dark finish and moderate corrosion protection.

Construction machinery engine mounts – safety wire through hole prevents loosening.

Mining vibrating screens – transverse hole with cotter pin.

Railway vehicle bogie access covers – double security against vibration.

Large fan rotor locking rings – wire-locked drilled screws.

Agricultural harvester blade holders – black zinc resists mud and wear.

Dual function: knurling + hole – hand starting convenience plus wire-locking anti-loosening.

Black zinc finish – dark, non-reflective appearance.

Medium diameters M8-M10 – common for moderate loads.

Positive mechanical locking – safety wire outperforms spring washers.

High-strength carbon steel – Grade 10.9 for high preload.