S-91251A080 5-40 x 1" 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 the black-oxide finish extends service life and maintains integrity in harsh or humid industrial environments.
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant assemblies, minimizing loosening over time.
• Partially threaded design allows for controlled clamping force and easier alignment in components requiring specific grip lengths.
• High hardness (Rockwell C37) offers excellent wear resistance, maintaining thread integrity through repeated installation and removal cycles.
• Compact 3/32" hex drive enables easy installation in confined spaces with standard tools, speeding up assembly processes.
• Compliance with ASTM A574, RoHS 3, and REACH ensures material consistency, environmental safety, and suitability for regulated industries.

Professional Applications & Engineering Value

Engineered for precision and durability, these 5-40 UNC Socket Head Cap Screws in Black-Oxide Alloy Steel address common industrial challenges such as vibration-induced loosening and corrosion. The coarse UNC thread and Class 3A fit provide superior holding power in metals and plastics, ideal for machinery, automotive, and aerospace assemblies where reliability is critical. The partially threaded shank allows exact positioning without over-tightening, while the 170,000 psi tensile strength and Rockwell C37 hardness ensure long-term performance in high-load environments. These screws are a trusted solution for engineers seeking fasteners that combine strength, compliance, and ease of installation.

Specification Summary & Compliance

This screw adheres to Class 3A thread fit for precise UNC threading with a 5-40 coarse thread and right-hand direction. It meets ASTM A574 specifications for alloy steel socket head cap screws, ensuring material and manufacturing consistency. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) standards, it is free of hazardous substances, making it suitable for global industrial use. Dimensions include a 1" length, 0.205" head diameter, and 3/32" hex drive, providing reliable performance in inch-system applications.