S-91309A556 1/4"-20 x 3 1/2" ASME B18.2.1, ASTM A307 Low-Strength Steel Hex Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc plating, extending service life in harsh industrial environments.
• High tensile strength of 60,000 psi ensures reliable performance under heavy loads and vibrations.
• Coarse UNC threading provides quick and easy installation, reducing assembly time and labor costs.
• Class 2A thread fit offers consistent, precise engagement for secure fastening without cross-threading risks.
• External hex drive design allows for high-torque application using standard tools, enhancing installation efficiency.
• Full threading along the 3 1/2" length enables versatile use across various material thicknesses and applications.
• Compliance with ASME B18.2.1, RoHS 3, and REACH guarantees quality, safety, and environmental standards are met.

Professional Applications & Engineering Value

This 1/4"-20 hex head screw is engineered from high-strength steel and finished with zinc plating to combat corrosion in demanding settings like construction, machinery assembly, and automotive industries. The UNC coarse thread and Class 2A fit minimize stripping and ensure tight, reliable connections in materials prone to vibration or thermal expansion. With a tensile strength of 60,000 psi and Rockwell B69 hardness, it addresses common failures in heavy-duty applications, providing durability and reducing maintenance needs. Ideal for industrial fastening solutions, it supports efficient, long-term performance where precision and compliance are critical.

Specification Summary & Compliance

This screw features a 1/4"-20 UNC coarse thread with Class 2A dimensional accuracy for consistent fit. It meets ASME B18.2.1 manufacturing standards and is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and quality assurance.