S-91273A167 1/4"-28 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 Stainless Steel construction, ideal for harsh environments and long-term reliability.
• Enhanced torque transmission and slip resistance from the knurled socket head and 1/8" hex drive, ensuring secure installation.
• High mechanical strength with 70,000 psi tensile strength and Rockwell B55 hardness for demanding industrial applications.
• Precise alignment and smooth rotation provided by the 3/8" shoulder length and standard shoulder fit, reducing wear on mating parts.
• Reliable fine thread engagement with 1/4"-28 UNF Class 2A threads, offering excellent vibration resistance and secure fastening.
• Compliance with environmental regulations, being RoHS 3 and REACH compliant for safe and sustainable use.
• Consistent dimensional accuracy with tight tolerances on shoulder diameter and length, ensuring repeatable performance in assemblies.

Professional Applications & Engineering Value

This socket head shoulder screw is engineered to address critical challenges in precision machinery and industrial equipment. The 18-8 Stainless Steel material provides excellent corrosion resistance, making it suitable for applications exposed to moisture, chemicals, or outdoor conditions, thereby extending service life and reducing maintenance. The 3/8" shoulder length acts as a precise pivot or spacer, minimizing friction and misalignment in moving parts like linkages, gears, and bearings. Combined with the 1/4"-28 UNF fine thread and Class 2A fit, it ensures secure fastening under vibration, common in automotive, aerospace, and manufacturing assemblies. The knurled head and hex drive enhance grip during installation, preventing tool slippage and ensuring consistent torque application for reliable performance in high-stress environments.

Specification Summary & Compliance

This shoulder screw features a 1/4"-28 UNF fine thread with Class 2A tolerance for precise fit, a shoulder diameter of 1/4" with tolerance from -0.004" to -0.002", and a shoulder length of 3/8" with tolerance from -0.005" to 0.005". It complies with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free from hazardous substances and suitable for various industrial and engineering applications requiring durability and environmental safety.