S-91257A587 5/16"-18 x 1 1/2" 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 high-stress industrial applications
• Superior Corrosion Protection - Zinc Yellow-Chromate plating provides enhanced resistance to rust and environmental degradation
• Optimized Thread Engagement - Class 2A thread fit and UNC coarse threading enable faster installation and secure fastening in various materials
• Exceptional Durability - Rockwell C33 hardness rating maintains structural integrity under repeated stress and vibration
• Industry-Standard Compliance - Meets ASME B18.2.1 and SAE J429 specifications for guaranteed quality and interchangeability
• Enhanced Grip and Torque Application - External hex drive design allows for high torque installation with standard tools
• Environmental Responsibility - RoHS 3 and REACH compliance ensures safe use in regulated industries and applications

Professional Applications & Engineering Value

These Grade 8 hex head screws deliver critical performance in demanding industrial environments where failure is not an option. The zinc yellow-chromate plated steel construction provides superior corrosion resistance for outdoor equipment, machinery, and structural applications exposed to harsh conditions. The 5/16"-18 UNC coarse thread design ensures rapid installation and excellent holding power in both metal and composite materials, while the partial threading allows for precise clamp load distribution. Engineered to withstand extreme vibration and heavy loads, these high-strength bolts are ideal for construction equipment, automotive assemblies, and industrial machinery where 150,000 PSI tensile strength and Rockwell C33 hardness prevent stripping and deformation under maximum stress conditions.

Specification Summary & Compliance

Manufactured to exacting Class 2A thread fit tolerances with UNC coarse threading (5/16"-18) and partial threading extending 7/8" minimum. These 1-1/2" hex head screws comply with ASME B18.2.1 and SAE J429 Grade 8 specifications, ensuring dimensional accuracy and mechanical properties. The fasteners are fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, making them suitable for use in regulated industries and international markets.