S-91247A120 5/16"-24 x 2 3/4" ASME B18.2.1, SAE J429 Medium-Strength Grade 5 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional Load-Bearing Capacity – With 120,000 psi tensile strength and Grade 5 classification, this screw reliably withstands high-stress applications without failure.
• Superior Corrosion Resistance – Zinc plating provides a durable protective barrier, extending service life in harsh industrial environments.
• Precision Thread Engagement – Fine UNF threads and Class 2A fit ensure secure, vibration-resistant connections with minimal risk of loosening.
• Optimized for Heavy-Duty Use – Rockwell C25 hardness offers excellent wear resistance, maintaining integrity under repeated loading cycles.
• Efficient Installation & Removal – External hex drive and standard 1/2" head width allow for quick, tool-friendly fastening with common wrenches.
• Versatile Partial Threading – Combines strong grip in the threaded section with smooth shank stability, ideal for materials requiring clamped and unthreaded engagement.
• Regulatory Peace of Mind – Complies with RoHS 3 and REACH, ensuring safe, environmentally responsible sourcing for global supply chains.

Professional Applications & Engineering Value

Engineered for demanding industrial applications, this Grade 5 hex head screw addresses critical fastening challenges where reliability is non-negotiable. The zinc plated steel construction resists rust and corrosion, making it suitable for outdoor machinery, automotive assemblies, and structural frameworks exposed to moisture. Its fine UNF thread and Class 2A fit deliver superior clamping force and vibration resistance, preventing joint failure in dynamic loads. The partially threaded design allows the unthreaded portion to act as a precision pilot or shear plane, reducing stress concentration. Whether used in heavy equipment, construction, or manufacturing, this fastener ensures long-term performance, backed by ASME B18.2.1 and SAE J429 standards for consistent quality and interchangeability.

Specification Summary & Compliance

This screw adheres to Class 2A thread fit tolerances per UNF standards, ensuring precise, consistent engagement. Manufacturing and material specifications meet ASME B18.2.1 and SAE J429 for Grade 5 fasteners, guaranteeing dimensional accuracy and mechanical properties. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming the absence of restricted hazardous substances and supporting sustainable procurement practices.