S-91286A412 5/8"-11 x 3 1/2" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Maximum Load-Bearing Capacity - With 150,000 PSI tensile strength and Grade 8 classification, this screw handles extreme mechanical stress without failure
• Superior Corrosion Protection - Zinc-flake coating provides exceptional resistance to rust and chemical exposure in harsh industrial environments
• Optimized Thread Engagement - UNC coarse thread pattern ensures faster installation and reduced cross-threading risk compared to fine threads
• Precise Torque Transmission - External hex drive with 15/16" head width delivers reliable wrench grip and consistent clamping force
• Enhanced Durability - Rockwell C33 hardness maintains structural integrity under repeated loading and vibration
• Versatile Partial Threading - 1 1/2" minimum thread length allows for both secure fastening and adjustment flexibility
• Regulatory Compliance Assurance - Meets critical industry standards while being RoHS 3 and REACH compliant for global applications

Professional Applications & Engineering Value

This Grade 8 hex head screw delivers exceptional engineering value in demanding applications where failure is not an option. The zinc-flake coated steel construction addresses critical corrosion challenges in manufacturing facilities, outdoor equipment, and marine environments. The 5/8"-11 UNC coarse thread configuration provides superior holding power in structural steel connections, heavy machinery assembly, and construction applications where vibration resistance is paramount. With partial threading and Class 2A thread fit, installers benefit from easier alignment and consistent clamping force distribution. The external hex drive design ensures compatibility with standard industrial tools while the 3 1/2" length accommodates thick material stacks common in structural frameworks and equipment bases.

Specification Summary & Compliance

Manufactured to precise Class 2A thread fit tolerances with 5/8"-11 UNC coarse threads and 1 1/2" minimum thread length. Complies with ASME B18.2.1 and SAE J429 Grade 8 specifications for dimensional accuracy and mechanical properties. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance requirements for environmental safety and restricted substances.