S-91257A975 1"-8 x 7 1/2" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 150,000 psi ensures reliable performance in high-stress applications, reducing the risk of fastener failure.
• Superior corrosion resistance from zinc yellow-chromate plating extends service life in harsh or outdoor environments.
• High hardness rating (Rockwell C33) provides excellent wear resistance and durability under heavy loads.
• Coarse UNC threading allows for faster installation and better performance in materials prone to vibration or debris.
• Partially threaded design offers optimal clamping force and secure fastening in structural assemblies.
• Class 2A thread fit ensures consistent, easy assembly with standard nuts and tapped holes, minimizing production delays.
• External hex drive enables high torque application with common tools, speeding up maintenance and assembly processes.

Professional Applications & Engineering Value

Engineered for demanding industrial settings, this Grade 8 hex head screw combines high-strength steel and zinc yellow-chromate plating to address common challenges like corrosion, vibration loosening, and heavy load stress. The 1"-8 UNC coarse thread provides quick engagement and reliable holding power in construction equipment, machinery frames, and structural steel connections, where partial threading ensures precise clamp load distribution. Ideal for heavy-duty applications requiring compliance with rigorous standards, it minimizes downtime and maintenance costs through robust tensile strength and corrosion protection.

Specification Summary & Compliance

This fastener meets ASME B18.2.1 and SAE J429 specifications, with Class 2A thread fit for consistent dimensional accuracy. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and material reliability for global industrial use.