S-91268A120 1 1/8"-7 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, these screws withstand extreme mechanical stresses, reducing failure risks in heavy-duty applications.
• Superior Durability & Wear Resistance - Rockwell C33 hardness ensures long-lasting performance under high vibration and repetitive loads, minimizing replacement frequency.
• Optimized Thread Engagement - Coarse UNC threads with Class 2A fit provide reliable fastening in structural steel and machinery, resisting loosening under dynamic conditions.
• Enhanced Corrosion & Chemical Resistance - Steel construction combined with RoHS 3 and REACH compliance ensures environmental safety and longevity in harsh industrial settings.
• Precision Manufacturing Standards - Full compliance with ASME B18.2.1 and SAE J429 Grade 8 guarantees dimensional accuracy and interchangeability in OEM assemblies.
• Efficient Installation & Removal - External hex drive and 1 11/16" head width allow high-torque application with standard tools, speeding up maintenance cycles.
• Versatile Partial Threading - 2 1/2" minimum thread length on a 4 1/2" shank provides focused clamping force where needed, ideal for thick-section materials.

Professional Applications & Engineering Value

Engineered for heavy machinery, structural steel frameworks, and industrial equipment assembly, these Grade 8 hex head screws address critical challenges in high-stress environments. The 1 1/8"-7 UNC coarse thread design ensures rapid installation and superior resistance to vibrational loosening in construction and manufacturing applications. Made from high-strength steel with Rockwell C33 hardness, they prevent thread stripping and maintain clamp load under cyclic loading. The partially threaded configuration concentrates force on joint interfaces, reducing stress concentration in heavy-duty bolting systems. Compatible with standard external hex drive tools, they streamline maintenance in mining, transportation, and energy sectors where reliability is non-negotiable.

Specification Summary & Compliance

This Grade 8 hex head screw features precision Class 2A thread fit with 1 1/8"-7 UNC coarse threading and 4 1/2" length. Manufacturing strictly adheres to ASME B18.2.1 and SAE J429 Grade 8 specifications for dimensional consistency. Regulatory compliance includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental standards, ensuring safe use in global industrial supply chains.