S-91273A169 1/4"-28 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 Stainless Steel construction, ideal for harsh industrial environments and extending service life.
• Enhanced assembly precision and alignment due to the precisely machined 3/8" shoulder length with tight tolerances, reducing component wear.
• High-strength performance under load with a tensile strength of 70,000 psi and a minimum shear strength of 35,000 psi for reliable, durable connections.
• Secure, non-slip fastening provided by the knurled head and standard 1/8" hex drive, allowing for high torque application without stripping.
• Fine-threaded accuracy and vibration resistance from the 1/4"-28 UNF Class 2A thread, ensuring a tight, secure fit in precision assemblies.
• Broad regulatory compliance with RoHS 3 and REACH standards, making it suitable for use in regulated global markets.
• Versatile right-hand thread design for standard installation processes, improving efficiency in automated or manual assembly lines.

Professional Applications & Engineering Value

This socket head shoulder screw is engineered to address critical alignment and pivot point challenges in precision applications. The 18-8 Stainless Steel material offers excellent resistance to corrosion and oxidation, which is vital for machinery operating in moist or chemically aggressive environments. The 3/8" shoulder length with controlled tolerances acts as a precise datum for locating parts like gears, bearings, and linkages, minimizing misalignment and subsequent wear. The UNF fine thread (1/4"-28) provides a higher number of threads per inch compared to coarse threads, resulting in superior vibration resistance and a tighter clamp force in high-tensile strength assemblies. Combined with the knurled head and hex drive, it ensures secure handling and installation, making it a reliable component in automated equipment, robotics, and precision instruments where repeatability and durability are paramount.

Specification Summary & Compliance

This shoulder screw conforms to Class 2A thread fit tolerances for a free-spinning assembly with a standard shoulder fit. The shoulder diameter is 1/4" with a tolerance of -0.004" to -0.002", and the shoulder length is 5/8" with a tolerance of -0.005" to 0.005", ensuring high dimensional accuracy. The UNF thread standard is maintained, and the product is manufactured to be RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, adhering to strict environmental and safety regulations for industrial components.