S-91251A807 5/8"-11 x 3 1/4" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with black-oxide coating, extending service life in harsh industrial environments
• Superior load-bearing capacity with 170,000 psi tensile strength for heavy-duty applications
• Precision Class 3A thread fit ensures reliable engagement and vibration resistance
• Optimized torque transmission through 1/2" hex drive design for secure installation
• Enhanced durability with Rockwell C37 hardness maintaining structural integrity under stress
• Versatile partial threading allows both clamping and alignment functions in assembly
• Regulatory compliance meets ASTM A574, RoHS 3 and REACH standards for global acceptance

Professional Applications & Engineering Value

These black-oxide alloy steel socket head cap screws deliver critical performance where standard fasteners fail. The UNRC coarse thread configuration combined with Class 3A precision prevents loosening in high-vibration machinery while enabling rapid assembly. The partially threaded design provides unthreaded shank sections for precise component alignment in jigs, fixtures, and heavy equipment. With 170,000 psi tensile strength, they withstand extreme mechanical loads in construction equipment, automotive manufacturing, and industrial machinery. The corrosion-resistant black-oxide finish ensures reliable operation in humid or chemically aggressive environments without compromising the Rockwell C37 hardness that maintains thread integrity through repeated disassembly cycles.

Specification Summary & Compliance

Manufactured to ASTM A574 specifications with Class 3A thread fit (equivalent to ISO 4g6g tolerance) for precision engagement. Features 5/8"-11 UNRC coarse threads with 1 3/4" minimum thread length on a 3 1/4" overall partially threaded configuration. Full compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations for international industrial use.