S-90585A127 4-40 x 1 1/2" ASME B18.3, ASTM F879 Stainless Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 316 stainless steel construction and passivated finish, ideal for harsh environments and extended service life.
• High-strength performance offering 70,000 psi tensile strength and Rockwell B55 hardness for reliable, durable fastening under load.
• Precise thread engagement with Class 3A fit and 4-40 UNC coarse threading, ensuring secure connections and reduced cross-threading risks.
• Efficient installation and flush finish due to the flat head with 82° countersink angle and hex drive, allowing for neat, low-profile assemblies.
• Full threading along the 1-1/2" length provides maximum grip and versatility in various material thicknesses.
• Compliance with industry standards including ASME B18.3, ensuring consistent quality and interchangeability in professional applications.
• Environmental and safety adherence with RoHS 3 and REACH compliance, supporting sustainable and safe manufacturing practices.

Professional Applications & Engineering Value

This 316 stainless steel flat head screw is engineered to address critical challenges in industrial settings, such as corrosion in marine, chemical, or outdoor environments. Its passivated finish enhances surface durability, while the 4-40 UNC coarse thread and Class 3A fit deliver precise, vibration-resistant connections in machinery, electronics, and structural assemblies. The flat head design with an 82° countersink ensures a smooth, flush installation, minimizing protrusions and improving safety in high-traffic areas. Ideal for applications demanding high tensile strength (70,000 psi) and reliable performance, this screw supports efficient maintenance and long-term reliability in B2B procurement for OEM and MRO needs.

Specification Summary & Compliance

This screw adheres to Class 3A thread fit tolerances for high precision, with 4-40 UNC coarse threading and a right-hand thread direction. It meets ASME B18.3 specifications for dimensional consistency and is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring no hazardous substances and supporting global environmental standards.