S-90665A177 5/16"-18 x 1" ASTM A574 Alloy Steel Low-Profile Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 140,000 psi ensures reliable performance under high-stress conditions, reducing the risk of fastener failure in demanding applications.
• Superior corrosion resistance with zinc plating protects against rust and environmental degradation, extending service life in harsh industrial settings.
• Precision Class 3A thread fit provides tight, secure connections with minimal play, enhancing assembly accuracy and vibration resistance.
• Low-profile socket head design allows for installation in confined spaces while offering high torque capability with a standard hex drive.
• High hardness rating (Rockwell C39) maintains thread integrity and resistance to wear, ensuring long-term durability and reusability.
• Full threading along the 1" length enables versatile positioning and uniform clamping force across the entire fastener.
• Compliance with ASTM A574 and environmental regulations guarantees consistent quality and safe use in regulated industries.

Professional Applications & Engineering Value

This zinc-plated alloy steel socket head cap screw is engineered to address critical challenges in industrial assembly, such as vibration loosening and corrosion-induced failure. The 5/16"-18 UNC coarse thread with Class 3A fit ensures rapid installation and secure fastening in materials where fine threads may strip or require higher torque. The low-profile head and hex drive design facilitate access in tight spaces, common in machinery, automotive, and equipment manufacturing. With a tensile strength of 140,000 psi and Rockwell C39 hardness, it withstands dynamic loads and repeated use, making it ideal for high-stress applications like structural frames, precision tools, and heavy-duty enclosures. The zinc plating adds a protective barrier, crucial for outdoor or humid environments, ensuring long-term reliability without frequent maintenance.

Specification Summary & Compliance

This socket head cap screw adheres to UNC coarse thread standards with a precise Class 3A thread fit for superior engagement and minimal tolerance. Dimensions include a 5/16"-18 thread size, 1" length, and fully threaded design. It meets ASTM A574 specifications for high-strength alloy steel fasteners, ensuring consistent material and manufacturing quality. The product is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, confirming adherence to environmental and safety regulations for hazardous substances.