S-91259A322 7/8"-9 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capacity with 140,000 psi tensile strength and 84,000 psi shear strength for reliable performance in high-stress environments.
• Precision-engineered Class 3A thread fit ensures tight, secure fastening and reduces the risk of loosening under vibration or dynamic loads.
• Durable black oxide finish provides corrosion resistance and extends service life in demanding industrial conditions.
• Knurled head with 5/8" hex drive offers superior grip and easy installation, even in confined spaces or with gloved hands.
• Rockwell C32 hardness delivers excellent wear resistance and maintains dimensional stability under heavy use.
• 5" shoulder length with tight tolerances allows for precise alignment and spacing in assemblies, minimizing component wear.
• Compliance with ASME B18.3, RoHS 3, and REACH ensures adherence to industry standards and environmental regulations for safe, global use.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address critical challenges in heavy machinery, automation systems, and structural assemblies where high tensile strength and precise alignment are paramount. The 7/8"-9 UNC coarse thread with Class 3A fit provides rapid installation and superior clamping force, reducing assembly time while resisting vibrational loosening. The black oxide finish enhances corrosion resistance, making it suitable for environments exposed to moisture or chemicals. With a 5" shoulder length and controlled diameter tolerance, it acts as a reliable pivot or spacer in conveyor systems, robotic arms, and press fittings, ensuring minimal backlash and extended component life. Its knurled socket head and 5/8" hex drive facilitate quick tool engagement, streamlining maintenance in tight industrial setups.

Specification Summary & Compliance

This shoulder screw features a 7/8"-9 UNC thread with Class 3A fit for high-precision engagement, and a shoulder diameter of 1 1/4" with tolerance of -0.004" to -0.002" for accurate alignment. The shoulder length is 5" with a tolerance of -0.005" to 0.005", ensuring consistent performance. Manufactured to ASME B18.3 specifications, it is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting stringent industry and environmental standards for safe, reliable use in global markets.