S-90585A039 1/4"-20 x 1 1/8" 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 environments and chemical exposure
• High tensile strength of 70,000 psi ensures reliable performance under heavy loads and vibration
• Precise Class 3A thread fit provides secure, tight fastening with minimal risk of stripping or loosening
• Passivated finish enhances surface durability and extends service life by preventing oxidation
• 82° countersink angle and flat head design allows for flush mounting, reducing snagging and improving aesthetics
• Hex drive (5/32") enables easy installation and removal with standard tools, saving time on assembly lines
• Full threading ensures consistent grip along the entire length, maximizing holding power in various materials

Professional Applications & Engineering Value

This 1/4"-20 UNC flat head screw in 316 stainless steel is engineered to address critical challenges in industrial settings, such as corrosion from moisture, chemicals, or saltwater environments. The coarse UNC threading and Class 3A fit deliver exceptional vibration resistance, preventing loosening in machinery, automotive assemblies, and structural frameworks. Its passivated finish adds an extra layer of protection against pitting and rust, making it a reliable choice for heavy-duty fasteners in marine, chemical processing, and outdoor equipment. With a Rockwell B55 hardness and full threading, it ensures durable, long-term performance where precision and reliability are non-negotiable.

Specification Summary & Compliance

This screw adheres to ASME B18.3 standards for dimensional accuracy, including a head diameter of 0.531" and length of 1 1/8". The UNC coarse thread with Class 3A fit guarantees tight tolerances, while the inch system measurements ensure compatibility with North American specifications. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its safety and environmental responsibility for global industrial use.