S-91375A759 1/2"-20 x 4" ASME B18.3 Set Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with black-oxide coating, extending service life in demanding industrial environments.
• Exceptional holding power provided by Class 3A thread fit, ensuring tight, secure fastening with minimal backlash.
• High-strength durability from alloy steel and Rockwell C45 hardness, resisting wear and deformation under heavy loads.
• Easy installation and removal with a 1/4" hex drive, allowing for high torque application in confined spaces.
• Secure, non-slip grip from the cup tip design, which bites into surfaces to prevent component movement.
• Reliable fine thread engagement with 1/2"-20 UNF right-hand threads, offering superior resistance to vibration loosening.
• Broad compliance with ASME B18.3, RoHS 3, and REACH, ensuring safety and regulatory acceptance for global use.

Professional Applications & Engineering Value

This black-oxide alloy steel set screw is engineered to address critical challenges in machinery assembly, automotive, and heavy equipment. Its headless design and hex drive enable flush mounting in tight spaces, while the Class 3A UNF fine threads provide a precise, vibration-resistant fit that maintains alignment under dynamic loads. The cup tip concentrates pressure for a firm grip on shafts and collars, preventing slippage that can lead to equipment failure. With Rockwell C45 hardness, it withstands repetitive stress, making it ideal for permanent or semi-permanent fastening in high-torque industrial applications where reliability is non-negotiable.

Specification Summary & Compliance

This set screw features a 1/2"-20 UNF fine thread with Class 3A fit for high precision and a right-hand thread direction. It meets ASME B18.3 manufacturing specifications and is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free of hazardous substances and suitable for international industrial use.