S-90550A770 1/4"-20 x 1 1/2" ASME B18.3, ASTM F879, MIL-DTL-18240 Venting Stainless Steel Hex-Drive Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel construction, ideal for harsh industrial environments and outdoor applications.
• Enhanced fastening efficiency through the UNC coarse thread and Class 3A thread fit, ensuring reliable, vibration-resistant connections.
• Optimized venting performance with the vented design and 0.062" vent diameter, preventing pressure buildup in sealed assemblies.
• Flush, professional installation enabled by the standard flat head profile and 82° countersink angle for a smooth, unobtrusive finish.
• High torque application capability with the 5/32" hex drive, allowing for secure tightening without stripping.
• Full thread engagement along the 1-1/2" length, providing maximum grip strength and load distribution.
• Regulatory peace of mind with compliance to ASME B18.3, ASTM F879, MIL-DTL-18240, RoHS 3, and REACH standards.

Professional Applications & Engineering Value

This 18-8 stainless steel flat head screw is engineered to address critical challenges in industrial and mechanical assemblies. Its corrosion-resistant material ensures long-term reliability in humid, chemical, or marine environments, reducing maintenance costs and downtime. The UNC coarse thread and Class 3A thread fit deliver superior holding power and vibration resistance, making it ideal for machinery, automotive, and aerospace applications where joint integrity is paramount. The vented design with an 82° countersink angle allows for pressure equalization in enclosed systems, preventing seal failure. Combined with a hex drive for high-torque installation, this screw provides a durable, precision-fastening solution that meets rigorous ASME B18.3 and military specifications.

Specification Summary & Compliance

This screw adheres to precise dimensional standards, including a 1/4"-20 UNC coarse thread with Class 3A thread fit for tight tolerance assembly. It is manufactured in compliance with ASME B18.3, ASTM F879, and MIL-DTL-18240 specifications, ensuring consistent quality and performance. The product is fully RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting environmental and safety regulations for global industrial use.