S-90128A119 4-40 x 1 1/4" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 psi ensures reliable performance under high-stress conditions, reducing the risk of fastener failure in demanding applications.
• Superior corrosion resistance from zinc plating protects against rust and environmental degradation, extending service life in harsh industrial environments.
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant assemblies, minimizing loosening in critical machinery.
• High hardness rating (Rockwell C37) offers excellent wear resistance, maintaining thread integrity through repeated installation and removal cycles.
• Hex socket drive design allows for high torque application with standard tools, enabling efficient assembly in confined spaces.
• Partially threaded configuration combines secure clamping with unthreaded shank strength, ideal for applications requiring precise grip length.
• Comprehensive compliance with ASTM A574, RoHS 3, and REACH ensures material consistency and environmental safety for global industrial use.

Professional Applications & Engineering Value

These 4-40 UNC socket head cap screws deliver critical engineering solutions where space constraints and high strength requirements intersect. The zinc-plated alloy steel construction provides essential corrosion protection for outdoor equipment, automotive assemblies, and manufacturing machinery exposed to moisture or chemicals. The coarse UNC thread with Class 3A fit ensures rapid installation and superior vibration resistance in high-cycle applications, while the hex drive socket head design enables high torque transfer without stripping. With 170,000 psi tensile strength and Rockwell C37 hardness, these screws maintain clamping force under extreme loads, preventing joint failure in critical structural applications. The partially threaded configuration offers precise bearing surface control, making them ideal for precision equipment, aerospace components, and heavy machinery where dimensional accuracy is paramount.

Specification Summary & Compliance

Manufactured to precise dimensional standards with Class 3A thread fit and UNC coarse thread spacing for consistent performance. These screws conform to ASTM A574 specification for alloy steel socket head cap screws, ensuring material and mechanical property consistency. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, making them suitable for global industrial applications with strict substance restrictions.