S-91257A887 3/4"-16 x 8" 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 a tensile strength of 150,000 PSI and Rockwell C33 hardness, this screw provides reliable performance in high-stress applications, reducing the risk of fastener failure.
• Superior Corrosion Resistance: The zinc yellow-chromate plating offers enhanced protection against rust and environmental degradation, extending the service life of your assemblies in harsh conditions.
• Precise Thread Engagement: UNF fine threads and Class 2A thread fit ensure tight, secure fastening with minimal vibration loosening, improving joint integrity.
• Optimized for Heavy-Duty Use: Grade 8 strength classification and partial threading design provide maximum clamping force where needed, ideal for critical structural connections.
• Easy Installation & Removal: The external hex drive and 1 1/8" head width allow for high torque application with standard tools, speeding up assembly and maintenance.
• Regulatory Compliance Assurance: Meets ASME B18.2.1 and SAE J429 standards, ensuring dimensional accuracy and performance reliability in industrial settings.
• Environmental Safety: RoHS 3 and REACH compliance guarantees that the fastener is free from hazardous substances, supporting sustainable manufacturing practices.

Professional Applications & Engineering Value

This Grade 8 hex head screw is engineered to address critical challenges in heavy machinery, construction, and automotive assemblies where high tensile strength and vibration resistance are paramount. The 3/4"-16 UNF fine thread configuration, combined with Class 2A thread fit, ensures precise alignment and reduced stress concentration, minimizing the risk of thread stripping under dynamic loads. The zinc yellow-chromate plating provides a durable barrier against corrosion, making it suitable for outdoor or humid environments. Its partial threading design concentrates strength in the engaged section, optimizing clamp load distribution. By complying with ASME B18.2.1, this fastener delivers consistent performance in bolted joints requiring 150,000 PSI tensile strength, enhancing safety and reducing maintenance cycles in industrial applications.

Specification Summary & Compliance

This screw adheres to Class 2A thread fit tolerances per UNF standards, ensuring dimensional accuracy for reliable assembly. It meets ASME B18.2.1 and SAE J429 specifications for Grade 8 fasteners, guaranteeing mechanical properties such as hardness and tensile strength. The product is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, confirming adherence to environmental regulations for hazardous substance restrictions.