S-91286A189 5/16"-24 x 1 1/2" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 150,000 psi ensures reliable performance in high-stress applications, reducing the risk of fastener failure.
• Superior corrosion resistance from the zinc-flake coating extends service life in harsh industrial environments, minimizing maintenance needs.
• Precise Class 2A thread fit with UNF fine threads provides secure, vibration-resistant connections for critical assemblies.
• High hardness (Rockwell C33) offers excellent wear resistance, maintaining thread integrity through repeated use.
• Partial threading design allows for optimal clamp force distribution, enhancing joint stability in structural applications.
• External hex drive enables easy installation with standard tools, reducing assembly time and labor costs.
• Compliance with major standards including ASME B18.2.1 and SAE J429 ensures consistent quality and interchangeability.

Professional Applications & Engineering Value

This Grade 8 hex head screw delivers critical engineering value through its high-strength steel construction and zinc-flake coating, specifically engineered to address common industrial challenges. The 5/16"-24 UNF fine threads with Class 2A fit provide superior resistance to vibration loosening in heavy machinery, automotive assemblies, and structural frameworks. The partial threading design concentrates clamping force where needed most, preventing joint failure in dynamic load conditions. With 150,000 psi tensile strength and Rockwell C33 hardness, this fastener maintains integrity under extreme pressure and repetitive stress cycles. The corrosion-resistant zinc-flake finish ensures long-term reliability in outdoor applications and chemically aggressive environments, making it ideal for construction equipment, industrial machinery, and transportation systems where durability and compliance with ASME B18.2.1 standards are paramount.

Specification Summary & Compliance

This hex head screw features precise Class 2A thread fit per UNF standards with 5/16"-24 fine threads and partial threading over a minimum 7/8" length. Manufactured to ASME B18.2.1 and SAE J429 specifications for Grade 8 fasteners, it complies with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring both mechanical performance and regulatory adherence for global industrial applications.