S-91257A849 3/4"-10 x 3 1/2" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capacity with 150,000 psi tensile strength for reliable performance in high-stress applications
• Superior corrosion resistance through zinc yellow-chromate plating that protects against harsh industrial environments
• Optimized thread engagement with UNC coarse threads and Class 2A fit ensuring secure fastening and vibration resistance
• Enhanced durability from Rockwell C33 hardness providing excellent wear resistance and long service life
• Easy installation and removal with external hex drive and 1 1/8" head width for standard tool compatibility
• Versatile partial threading allowing for both clamping and alignment functions in various assembly scenarios
• Regulatory compliance assurance meeting ASME B18.2.1, SAE J429, RoHS 3, and REACH standards for quality and safety

Professional Applications & Engineering Value

This Grade 8 hex head screw delivers critical engineering solutions for heavy machinery, structural assemblies, and industrial equipment where failure is not an option. The steel construction combined with zinc yellow-chromate plating provides exceptional corrosion protection in demanding environments, while the UNC coarse thread design ensures rapid assembly and superior resistance to vibration loosening. The partially threaded configuration offers dual functionality - the threaded portion secures components while the unthreaded shank maintains precise alignment in bolted connections. With 150,000 psi tensile strength and Rockwell C33 hardness, this fastener withstands extreme mechanical stresses in construction, automotive, and manufacturing applications where reliability and durability are paramount.

Specification Summary & Compliance

This 3/4"-10 hex head screw features precise Class 2A thread fit tolerance for consistent engagement and meets ASME B18.2.1 and SAE J429 Grade 8 specifications for dimensional accuracy and mechanical properties. The fastener is manufactured to comply with RoHS 3 (2015/863/EU) restrictions on hazardous substances and REACH (EC 1907/2006) regulations for chemical safety. With right-hand thread direction, external hex drive, and 3 1/2" length, this industrial-grade fastener delivers reliable performance while meeting international quality and environmental standards.