S-91375A556 1/4"-28 x 1/4" ASME B18.3, ASTM F912 Set Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance thanks to the black-oxide coating, extending service life in harsh industrial environments.
• Exceptional holding power and durability provided by the high-strength alloy steel and Rockwell C45 hardness, preventing stripping and deformation under high stress.
• Precise and secure fastening enabled by the Class 3A thread fit and fine UNF thread, ensuring minimal backlash and reliable performance in precision assemblies.
• Easy installation and high torque capability with the 1/8" hex drive, allowing for efficient assembly with standard tools.
• Flush, space-saving design due to the headless construction, ideal for applications where a protruding head is not feasible.
• Enhanced grip and resistance to loosening from the cup tip, which bites into the contact surface for a more secure lock.
• Guaranteed reliability and compliance with major industrial standards including ASME B18.3, ASTM F912, RoHS 3, and REACH, ensuring product safety and environmental responsibility.

Professional Applications & Engineering Value

This 1/4"-28 UNF set screw is engineered to solve critical fastening challenges in demanding industrial applications. Manufactured from black-oxide alloy steel, it provides excellent resistance to corrosion and wear, making it suitable for machinery, automotive components, and precision instruments exposed to oils, moisture, and varying temperatures. The headless design with a hex drive allows for compact installations in confined spaces, while the cup tip ensures a firm grip on shafts and collars, preventing slippage and maintaining alignment under vibration. The Class 3A thread fit and fine thread spacing deliver high clamping force and accuracy, reducing the risk of thread failure. Ideal for securing gears, pulleys, and knobs, this screw offers long-term reliability, minimizing maintenance needs and downtime in industrial set screw applications.

Specification Summary & Compliance

This set screw features a 1/4"-28 UNF fine thread with a Class 3A thread fit for precise tolerances and secure fastening. It complies with ASME B18.3 and ASTM F912 specifications, ensuring consistent quality and performance. The product is also RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, adhering to strict environmental and safety regulations for hazardous substances.