S-91283A244 1 1/4"-7 x 4" 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 ensures reliable performance in demanding applications, reducing the risk of fastener failure under heavy loads.
• Grade 5 steel construction with Rockwell C19 hardness provides excellent durability and resistance to wear, extending service life in industrial environments.
• Coarse UNC threads offer faster installation and better performance in materials prone to stripping or where quick assembly is required.
• Class 2A thread fit guarantees consistent, easy assembly with standard nuts while maintaining secure fastening integrity.
• Partially threaded design allows for precise clamping force control, ideal for applications requiring specific grip range and vibration resistance.
• External hex drive with 1 7/8" head width enables high-torque application using common tools, speeding up installation and maintenance.
• Full regulatory compliance with ASME B18.2.1, RoHS 3, and REACH ensures material safety and meets international industrial standards.

Professional Applications & Engineering Value

This Grade 5 hex head screw is engineered to address critical challenges in heavy machinery, structural steel connections, and industrial equipment assembly. The 1 1/4"-7 UNC coarse thread configuration provides superior grip in soft materials and faster installation times, while the partial threading design prevents joint loosening under dynamic loads. Manufactured from high-strength steel with Rockwell C19 hardness, it withstands extreme tension and shear forces in construction, automotive, and manufacturing applications. The external hex drive accommodates standard wrenches for secure tightening in confined spaces, making it ideal for maintenance operations where reliability and quick service access are paramount.

Specification Summary & Compliance

This 4" length hex head screw features 1 1/4"-7 UNC coarse threads with Class 2A thread fit per ASME/ANSI standards, ensuring precise dimensional accuracy and interchangeability. It meets ASME B18.2.1 and SAE J429 Grade 5 specifications for mechanical properties and is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, confirming the absence of restricted hazardous substances for safe industrial use worldwide.