S-91286A310 7/16"-20 x 3 1/2" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Maximum Load Capacity: Grade 8 classification with 150,000 psi tensile strength ensures reliable performance in high-stress applications
• Superior Corrosion Protection: Zinc-flake coating provides exceptional resistance against rust and environmental degradation
• Precision Thread Engagement: Class 2A thread fit with UNF fine threading offers secure fastening and vibration resistance
• Enhanced Durability: Rockwell C33 hardness maintains structural integrity under repeated stress and heavy loads
• Optimized Installation: External hex drive with 5/8" head width allows for easy torque application and secure tightening
• Versatile Application Design: Partially threaded configuration with 1 1/8" minimum thread length provides flexibility for various joint requirements
• Regulatory Compliance: Meets ASME B18.2.1 and SAE J429 standards, ensuring quality and interoperability

Professional Applications & Engineering Value

These Grade 8 hex head screws deliver exceptional engineering value in demanding industrial environments where failure is not an option. The zinc-flake coated steel construction addresses critical corrosion challenges in manufacturing facilities, outdoor equipment, and harsh operating conditions. The 7/16"-20 UNF fine thread configuration provides superior resistance to vibrational loosening, making these partially threaded hex screws ideal for heavy machinery, structural assemblies, and automotive applications. With 150,000 psi tensile strength and precise Class 2A thread fit, these fasteners eliminate concerns about joint integrity while the external hex drive ensures straightforward installation and maintenance accessibility. The combination of Rockwell C33 hardness and compliant threading standards guarantees consistent performance across industrial applications requiring reliable, high-strength fastening solutions.

Specification Summary & Compliance

This Grade 8 hex head screw features precise Class 2A thread fit with 7/16"-20 UNF fine threading and right-hand direction. The fastener meets ASME B18.2.1 and SAE J429 manufacturing specifications, ensuring dimensional accuracy and mechanical properties. Compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations confirms environmental responsibility and material safety standards. The 3 1/2" length with partial threading and external hex drive configuration maintains strict adherence to industrial fastening requirements for heavy-duty applications.