S-91268A128 1 1/8"-7 x 8" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Maximum Load-Bearing Capacity: Grade 8 classification and 150,000 psi tensile strength ensure reliable performance in the most demanding structural and machinery applications.
• Superior Wear and Deformation Resistance: Rockwell C33 hardness provides excellent durability, reducing the risk of head rounding or thread damage during high-torque installation.
li>Optimized for High-Torque Applications: The large external hex head (1 11/16" width) offers a secure grip for powerful wrenches, facilitating faster assembly and disassembly.
• Enhanced Vibration Resistance: Coarse 1 1/8"-7 UNC threads provide a stronger hold in a wider range of materials compared to fine threads, resisting loosening under dynamic loads.
• Precision Thread Fit for Reliable Engagement: Class 2A thread fit ensures consistent, smooth assembly with standard nuts, minimizing cross-threading and improving installation efficiency.
• Material and Construction Integrity: Manufactured from high-strength steel and compliant with ASME B18.2.1 and SAE J429 standards, guaranteeing dimensional accuracy and mechanical reliability.
• Safe for Regulated Environments: Full compliance with RoHS 3 and REACH regulations makes these screws suitable for use in environmentally conscious industrial sectors.

Professional Applications & Engineering Value

This Grade 8 Hex Head Screw is engineered for heavy-duty industrial applications where failure is not an option. The combination of high-strength steel, a coarse UNC thread, and a partially threaded design provides an optimal solution for connecting structural steel, heavy machinery, and large equipment frames. The external hex drive and substantial head size allow for the application of high torque, ensuring a tight, secure clamp in high-vibration environments. This design directly addresses common engineering challenges such as joint slippage, material fatigue, and corrosion-related degradation, delivering long-term structural integrity and reducing maintenance cycles in construction, mining, and manufacturing sectors.

Specification Summary & Compliance

This screw features a 1 1/8"-7 UNC coarse thread with a Class 2A thread fit for consistent, standard-compliant engagement. It is manufactured to meet the dimensional and mechanical requirements of ASME B18.2.1 and SAE J429 for Grade 8 fasteners. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free of restricted hazardous substances and suitable for use in regulated markets.