S-91251A943 1 1/4"-7 x 5 1/2" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 psi ensures reliable performance under extreme loads and prevents fastener failure in demanding applications
• Superior corrosion resistance from black-oxide coating extends service life and maintains appearance in harsh industrial environments
• Precision Class 2A thread fit provides consistent engagement and reduces assembly issues while maintaining dimensional accuracy
• High-strength alloy steel construction with Rockwell C37 hardness offers excellent wear resistance and durability for long-term use
• 7/8" hex drive design delivers maximum torque transmission and prevents tool slippage during installation and removal
• Partially threaded configuration allows for precise clamping force control and secure fastening in specific application requirements
• Industry compliance assurance with ASTM A574, RoHS 3, and REACH standards guarantees quality and environmental responsibility

Professional Applications & Engineering Value

These black-oxide alloy steel socket head cap screws deliver critical engineering solutions for industrial applications where high tensile strength and corrosion resistance are paramount. The 1 1/4"-7 UNRC coarse thread configuration ensures rapid assembly and disassembly while maintaining secure fastening in heavy machinery, construction equipment, and manufacturing systems. The 7/8" hex drive combined with the standard socket head profile provides superior torque transmission, preventing tool damage and ensuring consistent clamping force in high-vibration environments. The partially threaded design allows for precise load distribution, making these fasteners ideal for applications requiring specific unthreaded shoulder sections. With Rockwell C37 hardness and 170,000 psi tensile strength, these screws withstand extreme mechanical stresses while the black-oxide surface treatment resists corrosion in demanding operational conditions.

Specification Summary & Compliance

This socket head cap screw features precision Class 2A thread fit with 1 1/4"-7 UNRC coarse threads and 3 1/8" minimum thread length. Manufactured to ASTM A574 specifications for high-strength alloy steel fasteners, 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 industrial applications worldwide.