S-91257A852 3/4"-10 x 4 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 provided by zinc yellow-chromate plating, extending service life in demanding environments
• Optimized torque transmission through the external hex drive design and 1 1/8" head width for secure installation
• Enhanced thread engagement with Class 2A thread fit and coarse UNC threading for faster assembly and reduced cross-threading risk
• Grade 8 reliability backed by Rockwell C33 hardness for consistent performance under heavy mechanical loads
• Versatile partial threading allowing for both clamping force and unthreaded shank benefits in various assembly scenarios
• Regulatory compliance assurance meeting ASME B18.2.1, RoHS 3, and REACH standards for quality and environmental safety

Professional Applications & Engineering Value

These Grade 8 hex head screws deliver critical engineering solutions where high tensile strength and corrosion resistance are paramount. The 3/4"-10 UNC coarse thread configuration ensures rapid installation in heavy machinery, structural steel connections, and industrial equipment assemblies. The zinc yellow-chromate plating provides superior protection against environmental degradation, making these fasteners ideal for outdoor applications, manufacturing facilities, and automotive systems. With partial threading design, engineers benefit from precise clamp load distribution while the external hex drive enables high-torque installation without slippage. These screws effectively address common industrial challenges including vibration resistance, mechanical stress management, and long-term durability requirements in demanding operational environments.

Specification Summary & Compliance

Manufactured to precise dimensional standards with Class 2A thread fit tolerance and UNC coarse thread specifications. These hex head screws comply with ASME B18.2.1 mechanical standards and maintain RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental compliance. The 4 1/2" length with 1 3/4" minimum thread length ensures consistent performance across industrial applications while meeting all specified mechanical properties including 150,000 psi tensile strength and Rockwell C33 hardness requirements.