Grade 8, 5/16"-18 Hex Head Cap Screw, Black Oxide Steel, 8 in L, 5 PK

Upgrade your toolkit with confidence using the Grade 8 Hex Head Cap Screw—a high-strength, reliable fastener that meets both professional and industrial standards. Crafted from premium steel and finished in sleek black oxide for semi-dry environments, this 8‑inch long, partially threaded fastener is engineered for demanding applications.

Backed by SAE J429 quality and ASME B18.2.1 dimensional accuracy, this Grade 8 screw delivers an impressive tensile strength of 150,000 psi and a hardness rating of HRC 33, making it ideal for safety-critical assemblies, heavy-duty machinery, and construction applications.

Key Features

• Grade 8 Alloy Steel Construction – Offers superior tensile strength (150,000 psi) and hardness (HRC 33) for heavy-duty performance.

• 5/16″‑18 UNC Thread, 8″ Length – Coarse thread and partial threading accommodate diverse fastening needs with an overall head-turning length.

• External Hex Head (½″ Across Flats) – Easy, tool-friendly design for quick installation and removal, ideal for wrenches and impact tools.

• Black Oxide Finish – Provides mild corrosion resistance and a low-reflective, professional appearance.

• Standards-Compliant – Meets SAE J429 and ASME B18.2.1 for material strength and dimensional precision.

• 5‑Pack Convenient Packaging – Perfect for small project kits, repairs on the go, or stocking job boxes.
  

Technical Specifications