S-90303A140 5/16"-18 x 3/4" ASME B18.3, ASTM A574 Nylon-Tip Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Non-marring nylon tip prevents damage to sensitive surfaces during assembly and disassembly
• Exceptional 180,000 psi tensile strength provides reliable performance in high-stress applications
• Black-oxide finish on alloy steel offers enhanced corrosion resistance for extended service life
• Precision Class 3A thread fit ensures smooth installation and secure fastening in demanding environments
• Wide temperature tolerance (-50° to 250°F) maintains performance across diverse operating conditions
• Standard hex drive compatibility allows for easy installation with common industrial tools
• Rockwell C39 hardness rating delivers superior wear resistance and durability

Professional Applications & Engineering Value

This socket head cap screw combines black-oxide alloy steel construction with a specialized nylon tip to address critical challenges in precision assembly. The non-marring tip protects finished surfaces and delicate components in electronics, automotive, and machinery applications where surface integrity is paramount. Engineered with Class 3A thread fit and UNC coarse threading, it provides superior engagement in high-vibration environments while the 180,000 psi tensile strength ensures structural integrity under heavy loads. The combination of Rockwell C39 hardness and corrosion-resistant black-oxide surface treatment makes it ideal for industrial equipment, manufacturing fixtures, and precision instruments requiring repeated maintenance cycles.

Specification Summary & Compliance

This socket head cap screw features precision 5/16"-18 UNC coarse threading with Class 3A thread fit for superior dimensional accuracy. Manufacturing complies with ASME B18.3 specifications and material standards per ASTM A574. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use in global industrial applications.