S-90585A057 1/4"-28 x 1 1/2" ASME B18.3 Stainless Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 316 stainless steel construction, ideal for harsh industrial environments and chemical exposure.
• Enhanced mechanical durability from 70,000 psi tensile strength and Rockwell B55 hardness, ensuring reliable performance under load.
• Precise thread engagement with Class 3A fit and UNF fine threads, reducing the risk of stripping and improving vibration resistance.
• Optimized flush installation featuring an 82° countersink angle and flat head design for seamless, low-profile assemblies.
• Efficient installation and removal using a 5/32" hex drive, providing secure torque application and reducing tool slippage.
• Full thread coverage along the 1-1/2" length, offering consistent holding power across the entire fastener.
• Regulatory compliance assurance with ASME B18.3 standards and RoHS 3/REACH environmental directives for safe, global use.

Professional Applications & Engineering Value

These 1/4"-28 UNF flat head screws in 316 stainless steel are engineered to address critical challenges in demanding sectors like marine, chemical processing, and food equipment manufacturing. The passivated finish enhances surface integrity, preventing galling and providing an extra layer of protection against corrosive agents. With a Class 3A thread fit and fine UNF threading, these screws ensure tight, secure fastening in applications where vibration loosening is a concern. The 82° countersink angle allows for a flush mount, minimizing protrusions in machinery and structural assemblies. By combining high tensile strength and full threading, these fasteners deliver uniform stress distribution, making them ideal for high-stress connections that require long-term reliability and minimal maintenance.

Specification Summary & Compliance

This product adheres to precise dimensional tolerances, including a Class 3A thread fit for superior accuracy and a head diameter tolerance of -0.051" to 0". Manufactured in accordance with ASME B18.3 specifications, it ensures consistent performance in inch-based systems. The screw is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its safety for use in restricted substance-sensitive applications. Threads are UNF fine type, right-hand direction, and fully threaded along the 1-1/2" length, providing reliable fastening in industrial settings.