S-93310A581 5/16"-18 x 3/4" ASME B18.3, ASTM F879, MIL-DTL-18240 Thread-Locking Stainless Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Permanent vibration resistance with built-in nylon patch locking that maintains secure fastening without requiring separate locking components
• Superior corrosion protection through 18-8 stainless steel construction, ideal for harsh industrial environments and outdoor applications
• Exceptional mechanical strength delivering 70,000 psi tensile strength and Rockwell B55 hardness for heavy-duty fastening requirements
• Reliable performance across extreme temperatures with thread locker effectiveness maintained from -70° to 250°F
• Precision thread engagement through Class 3A thread fit ensuring consistent, secure mating with components
• Easy installation and removal with standard 3/16" hex drive that prevents stripping and allows high torque application
• Broad regulatory compliance meeting multiple industrial standards including ASME B18.3, ASTM F879, and MIL-DTL-18240

Professional Applications & Engineering Value

These nylon patch locking screws provide engineered solutions for vibration-prone applications where fastener integrity is critical. The 18-8 stainless steel construction offers excellent corrosion resistance for machinery, marine equipment, and outdoor structures, while the permanent thread locking technology eliminates the need for secondary locking mechanisms. The coarse UNC threads ensure rapid installation and superior holding power in softer materials and through-plate applications. With Class 3A thread fit precision and 70,000 psi tensile strength, these rounded head screws deliver reliable performance in automotive assemblies, industrial machinery, electrical enclosures, and construction equipment where vibration resistance and corrosion protection are paramount.

Specification Summary & Compliance

This 5/16"-18 x 3/4" screw features precision Class 3A thread fit with UNC coarse threading for optimal engagement. Manufacturing complies with ASME B18.3, ASTM F879, and MIL-DTL-18240 specifications, ensuring consistent quality and performance. The product is fully RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting current environmental regulations for hazardous substances. The nylon patch thread locker maintains effectiveness across the specified temperature range of -70° to 250°F, providing reliable vibration resistance in diverse operating conditions.