S-91259A441 1/2"-13 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional Durability: Crafted from high-grade alloy steel with a black oxide finish, providing superior corrosion resistance and extended service life in harsh industrial environments.
• High Tensile and Shear Strength: With a tensile strength of 140,000 psi and minimum shear strength of 84,000 psi, this screw ensures reliable performance under heavy loads and stress.
• Precision Thread Fit: Class 3A UNC coarse threads offer tight, secure fastening with reduced risk of loosening, ideal for high-vibration applications.
• Easy Installation and Removal: The 5/16" hex drive socket head and knurled texture allow for quick, tool-friendly assembly without slippage, saving time and labor costs.
• Accurate Shoulder Dimensions: Tight tolerances on shoulder diameter and length ensure precise alignment and smooth rotation in machinery and assemblies.
• Industry Compliance: Meets ASME B18.3 and ASTM A574 standards, along with RoHS 3 and REACH compliance, guaranteeing safety and environmental responsibility.
• Enhanced Hardness: Rockwell C32 hardness provides excellent wear resistance, maintaining integrity through repeated use and high-pressure conditions.

Professional Applications & Engineering Value

This shoulder screw is engineered to address common industrial challenges such as misalignment, wear, and corrosion in demanding applications. Made from alloy steel with a black oxide finish, it resists rust and degradation, making it suitable for automotive, aerospace, and heavy machinery where exposure to moisture and chemicals is frequent. The UNC coarse threads and Class 3A fit ensure quick, secure fastening in high-vibration settings, reducing maintenance downtime. The precise shoulder dimensions and knurled head facilitate accurate positioning and easy handling in assembly lines, while the socket head design with a 5/16" hex drive allows for efficient installation in confined spaces. Ideal for pivots, guides, and rotating components, this screw enhances operational reliability and longevity in industrial shoulder bolt applications.

Specification Summary & Compliance

This product adheres to precise dimensional standards, including a Class 3A thread fit for superior accuracy and a shoulder diameter tolerance of -0.004" to -0.002" with length tolerance of -0.005" to 0.005". It conforms to ASME B18.3 and ASTM A574 manufacturing specifications, ensuring consistent quality and performance. Additionally, it is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, supporting environmental safety and regulatory requirements in global markets.