S-91263A190 3/8"-16 x 7/8" ASME B18.3 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with zinc plating, extending service life in harsh industrial environments
• Superior tensile strength of 120,000 psi for reliable performance in high-stress applications
• Precise Class 3A thread fit ensures secure, vibration-resistant fastening and easy assembly
• 82° countersink angle allows for a flush, professional finish that minimizes protrusion risks
• Hex drive design provides high torque capability and reduces tool slippage during installation
• Full threading offers maximum grip length and uniform load distribution along the fastener
• Compliance with ASME B18.3, RoHS 3, and REACH guarantees quality and environmental safety for global supply chains

Professional Applications & Engineering Value

Engineered for demanding industrial settings, this 3/8"-16 UNC flat head screw combines zinc-plated alloy steel construction with a Class 3A thread fit to address critical challenges like vibration loosening and material fatigue. The coarse thread design enables quick installation in tough materials, while the flat head with 82° countersink ensures a seamless surface finish, ideal for machinery, automotive assemblies, and structural frameworks where safety and aesthetics matter. Its fully threaded body and hex drive enhance grip and torque transmission, reducing assembly time and maintenance costs in heavy-duty applications.

Specification Summary & Compliance

This screw adheres to ASME B18.3 standards for dimensional accuracy, featuring a Class 3A thread fit with UNC coarse threads for precise engagement. It meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance, ensuring it is free from hazardous substances and suitable for international industrial use. The specifications include a right-hand thread direction, Rockwell C32 hardness, and full threading for consistent performance.