S-90303A125 1/4"-20 x 1/2" ASME B18.3, ASTM A574 Nylon-Tip Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional Tensile Strength – With 180,000 psi tensile strength, this screw provides reliable load-bearing capacity in high-stress assemblies, reducing the risk of fastener failure.
• Non-Marring Nylon Tip – The soft nylon tip protects sensitive surfaces from scratches and damage during installation and use, ideal for finished products or delicate components.
• Precise Class 3A Thread Fit – Ensures tight, secure fastening with minimal backlash, improving assembly accuracy and vibration resistance in machinery.
• Corrosion-Resistant Black-Oxide Finish – The alloy steel with black-oxide coating offers enhanced durability against rust and wear in demanding industrial environments.
• Wide Temperature Tolerance – Nylon tip operates from -50° to 250°F, maintaining performance in varied thermal conditions without degrading.
• High Hardness for Longevity – Rockwell C39 hardness ensures the screw withstands repeated use and high torque applications without stripping or deformation.
• Standard Hex Drive Compatibility – 3/16" hex drive allows for easy installation with common tools, speeding up assembly processes and reducing labor time.

Professional Applications & Engineering Value

This black-oxide alloy steel socket head cap screw is engineered to address common industrial challenges such as surface damage and loosening under vibration. The non-marring nylon tip prevents marring on sensitive materials like aluminum or painted surfaces, making it perfect for automotive, electronics, and precision equipment assembly. Its UNC coarse thread and Class 3A fit provide quick, secure fastening in high-vibration environments, reducing maintenance needs. The combination of 180,000 psi tensile strength and Rockwell C39 hardness ensures durability in heavy-duty applications, from machinery frames to structural supports, while the black-oxide finish enhances corrosion resistance, extending service life in humid or abrasive conditions.

Specification Summary & Compliance

This screw adheres to ASME B18.3 specifications with a 1/4"-20 UNC coarse thread and Class 3A thread fit for precise dimensional accuracy. It is manufactured from alloy steel under ASTM A574 guidelines and complies with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and material integrity for global industrial use.