S-91309A566 1/4"-20 x 6" ASME B18.2.1, ASTM A307 Low-Strength Steel Hex Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc plating for extended service life in harsh industrial environments
• High tensile strength of 60,000 psi ensures reliable performance in demanding structural applications
• Coarse UNC threading provides faster assembly and reduced cross-threading risk compared to fine threads
• External hex drive design allows for high-torque installation with standard wrench tools
• Full threading along the 6" length offers maximum adjustability and holding power
• Class 2A thread fit guarantees consistent, reliable engagement with mating components
• Rockwell B69 hardness rating maintains structural integrity under repeated stress and vibration

Professional Applications & Engineering Value

These 1/4"-20 hex head screws with UNC coarse threading are engineered to solve critical fastening challenges in industrial assembly and construction. The zinc plated steel construction provides essential corrosion protection for outdoor equipment, machinery frames, and structural steel connections where environmental exposure is a concern. The external hex drive enables high-torque installation without stripping, while the coarse thread pitch ensures rapid assembly in production environments. With full threading along the entire 6" length, these screws offer superior grip range for variable material thicknesses, making them ideal for heavy-duty applications requiring maximum clamping force and vibration resistance.

Specification Summary & Compliance

Manufactured to ASME B18.2.1 and ASTM A307 specifications with Class 2A thread fit for consistent dimensional accuracy. Features UNC coarse threading (1/4"-20) with right-hand direction and external hex drive. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental standards, ensuring safe use across regulated industries.