S-90550A730 1/4"-20 x 5/8" 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.
• High-strength Class 3A thread fit ensures precise, secure fastening with reduced risk of loosening under vibration.
• Vented design allows pressure equalization, preventing fluid or gas buildup in sealed assemblies.
• Hex drive (5/32") provides high torque transmission and easy installation with standard tools.
• Fully threaded shank offers maximum grip and load distribution across the entire length.
• 82° countersink angle enables flush mounting for a smooth, professional finish.
• Compliance with ASME, ASTM, and MIL-DTL standards guarantees reliability for critical applications.

Professional Applications & Engineering Value

Engineered for demanding industrial settings, these 1/4"-20 UNC flat head screws in 18-8 stainless steel deliver exceptional durability and corrosion resistance, making them ideal for machinery, automotive, and aerospace assemblies. The coarse thread and Class 3A fit provide rapid installation and high clamping force, reducing assembly time while maintaining joint integrity. The vented feature is critical in pressurized systems, preventing failure from trapped gases. With a hex drive for secure tool engagement and full threading for uniform stress distribution, these screws solve common issues like stripping, seizing, and environmental degradation.

Specification Summary & Compliance

This screw adheres to UNC coarse thread standards with a Class 3A thread fit for high precision. Dimensions include a 1/4"-20 thread size, 5/8" length, and 0.531" head diameter. It meets ASME B18.3, ASTM F879, and MIL-DTL-18240 specifications, ensuring manufacturing consistency. The product is RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliant, supporting environmentally responsible procurement.