S-91283A176 1 1/8"-7 x 8" ASME B18.2.1, SAE J429 Medium-Strength Grade 5 Steel Hex Head Screws

Key Features & Benefits at a Glance

• High tensile strength of 100,000 psi provides superior load-bearing capacity for demanding structural applications.
• Grade 5 steel construction with Rockwell C19 hardness ensures excellent durability and resistance to wear in harsh industrial environments.
• Coarse UNC threading (1 1/8"-7) allows for faster installation and better performance in materials prone to stripping or vibration.
• Class 2A thread fit offers consistent, reliable engagement with standard nuts and tapped holes, reducing assembly time and improving joint integrity.
• External hex drive and hex head design enables high-torque application with common tools, ensuring secure fastening in high-stress scenarios.
• Partial threading provides an unthreaded shank for enhanced shear strength, ideal for applications requiring precise clamp load distribution.
• Compliance with ASME B18.2.1, RoHS 3, and REACH guarantees adherence to industry standards and environmental regulations for safe, reliable use.

Professional Applications & Engineering Value

This Grade 5 steel hex head screw is engineered to address critical challenges in heavy machinery, construction, and industrial assembly where high tensile strength and vibration resistance are paramount. The 1 1/8"-7 UNC coarse thread design minimizes cross-threading risks and ensures rapid installation in structural steel, equipment frames, and large-scale fabrications. With a Rockwell C19 hardness and 100,000 psi tensile strength, it withstands extreme loads and repetitive stress, reducing maintenance needs and downtime. The external hex drive facilitates efficient torque application, while partial threading optimizes clamp force distribution, making it a reliable choice for bolted connections in automotive, agricultural, and infrastructure projects requiring long-term performance under dynamic conditions.

Specification Summary & Compliance

This fastener features a 1 1/8"-7 UNC coarse thread with Class 2A thread fit for precise dimensional accuracy and interchangeability. It is manufactured in accordance with ASME B18.2.1 and SAE J429 Grade 5 specifications, ensuring consistent mechanical properties and reliability. The screw is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting stringent environmental and safety standards for industrial use.