S-90303A138 1/4"-20 x 1 1/2" ASME B18.3, ASTM A574 Nylon-Tip Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Non-marring nylon tip prevents surface damage on sensitive components, ideal for finished products and delicate assemblies.
• Exceptional tensile strength of 180,000 psi ensures reliable performance under high-stress conditions, reducing the risk of fastener failure.
• Black-oxide finish on alloy steel provides corrosion resistance and a durable, low-glare surface suitable for industrial environments.
• Class 3A thread fit offers superior precision and tighter tolerances for secure, vibration-resistant connections in critical applications.
• Wide temperature range (-50° to 250°F) allows consistent performance in extreme environments, from freezing cold to high-heat operations.
• Hex socket drive design enables high-torque installation with standard tools, improving assembly efficiency and reducing strip-out risks.
• Partially threaded shank provides enhanced grip and alignment, minimizing loosening in dynamic or vibrating machinery.

Professional Applications & Engineering Value

Engineered for demanding industrial settings, this Socket Head Cap Screw combines Black-Oxide Alloy Steel with a protective nylon tip to address common assembly challenges. The UNC coarse thread and Class 3A fit ensure quick, secure fastening in high-vibration equipment, while the non-marring tip safeguards finished surfaces in automotive, electronics, and precision machinery. With a Rockwell C39 hardness and robust 180,000 psi tensile strength, it resists shear and fatigue, extending service life in heavy-duty applications. Ideal for partially threaded configurations, it offers reliable clamping force where movement or thermal expansion occurs, reducing maintenance needs and enhancing operational safety.

Specification Summary & Compliance

This fastener adheres to ASME B18.3 specifications, ensuring dimensional accuracy and interchangeability. Threads are 1/4"-20 UNC with a Class 3A fit for precise engagement. It meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance, supporting environmental and safety standards. Manufactured from ASTM A574 alloy steel, it guarantees consistent performance in industrial fastening systems.