S-91253A583 5/16"-18 x 1" ASME B18.3 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with black-oxide coating, ideal for harsh industrial environments
• High tensile strength of 130,000 psi ensures reliable performance under heavy loads
• Precision Class 3A thread fit provides superior engagement and vibration resistance
• Fully threaded design offers maximum holding power across the entire length
• 82° countersink angle allows for flush mounting in standard applications
• Hex drive compatibility enables secure installation with common tools
• Compliance with major industry standards guarantees quality and regulatory acceptance

Professional Applications & Engineering Value

These 5/16"-18 UNC flat head screws with black-oxide alloy steel construction address critical engineering challenges in industrial assembly. The Class 3A thread fit and coarse UNC threading provide excellent resistance to loosening under vibration, while the fully threaded design ensures consistent clamping force throughout the fastener length. The 82° countersink angle and flat head profile create seamless surface finishes in machinery, automotive components, and structural applications. The black-oxide surface treatment significantly enhances corrosion resistance without compromising the 130,000 psi tensile strength, making these screws ideal for demanding environments where reliability and durability are paramount.

Specification Summary & Compliance

Manufactured to precise dimensional standards with Class 3A thread fit and UNC coarse threading. Complies with ASME B18.3 and ASTM F835 specifications for dimensional accuracy and mechanical properties. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental compliance requirements, ensuring safe use across industrial sectors.