S-91211A221 3/4"-10 x 2" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Thread-Locking Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capability with 150,000 psi tensile strength and Rockwell C33 hardness for reliable performance in demanding applications
• Secure vibration resistance through nylon patch thread locking that maintains integrity across temperature extremes from -55° to 250°F
• Superior corrosion protection with zinc yellow-chromate plating that extends service life in harsh industrial environments
• Optimized installation efficiency with UNC coarse threading and Class 2A fit ensuring smooth assembly and consistent engagement
• Heavy-duty construction meeting Grade 8 standards for critical applications requiring maximum fastener reliability
• Full-threaded design providing maximum grip length and uniform stress distribution along the entire fastener
• Standard-compliant engineering adhering to ASME B18.2.1 and SAE J429 specifications for guaranteed interchangeability and quality

Professional Applications & Engineering Value

This Grade 8 hex head screw delivers critical engineering solutions for heavy machinery, structural assemblies, and industrial equipment where vibration-induced loosening poses significant reliability concerns. The nylon patch thread locker technology provides permanent locking action without compromising the zinc yellow-chromate plated steel corrosion protection, making it ideal for outdoor equipment, automotive frames, and construction machinery exposed to environmental extremes. The UNC coarse threading with Class 2A fit ensures rapid installation in thick materials while maintaining precise tolerances. Engineered for high-stress applications, this fully threaded fastener distributes clamp load evenly, preventing joint failure in critical connections where 150,000 psi tensile strength is essential for structural integrity.

Specification Summary & Compliance

Manufactured to exacting Class 2A thread fit tolerances with UNC coarse threading (3/4"-10) and compliant with ASME B18.2.1 and SAE J429 specifications. The fastener meets industry standards for dimensional accuracy, mechanical properties, and performance requirements. The zinc yellow-chromate plating provides corrosion resistance while maintaining compliance with industrial fastener regulations and material specifications for consistent quality and reliability in professional applications.