S-90550A720 1/4"-20 x 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 environments and long-term reliability.
• Enhanced holding power and fastening security due to fully threaded UNC coarse threads and Class 3A fit for precise, vibration-resistant connections.
• Efficient installation and removal with a 5/32" hex drive, providing a secure grip and reducing the risk of tool slippage.
• Prevents pressure buildup through the integrated vented feature, crucial for applications requiring pressure equalization.
• Flush, low-profile seating with a standard flat head and 82° countersink angle, ensuring a smooth surface finish.
• Broad industry compatibility meeting ASME B18.3, ASTM F879, and MIL-DTL-18240 specifications for assured quality and performance.
• Environmentally compliant design adhering to RoHS 3 and REACH regulations, safe for various industrial uses.

Professional Applications & Engineering Value

This 1/4"-20 UNC flat head screw is engineered to address critical challenges in industrial assembly, such as corrosion-induced failure and pressure differentials in sealed systems. The 18-8 stainless steel material provides excellent resistance to rust and chemicals, extending service life in demanding environments like marine, chemical processing, and outdoor equipment. The vented design allows for pressure equalization, preventing accumulation that could compromise integrity in HVAC, pneumatic controls, or fluid systems. Combined with a hex drive for high-torque application and fully threaded coarse threads for rapid installation and strong grip, this screw ensures reliable performance in machinery, enclosures, and structural frameworks where durability and regulatory compliance are paramount.

Specification Summary & Compliance

This screw features a 1/4"-20 UNC coarse thread with Class 3A fit for high precision and strength. Dimensions include a head diameter of 0.531", length of 1/2", and vent diameter of 0.062". It conforms to ASME B18.3, ASTM F879, and MIL-DTL-18240 standards, ensuring consistent manufacturing quality. The product is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting environmental and safety regulations for industrial use.