S-91375A916 1"-8 x 3" ASME B18.3, ASTM F912 Set Screws

Key Features & Benefits at a Glance

• Exceptional holding security with Class 3A thread fit for precise, vibration-resistant fastening in demanding applications.
• Superior corrosion resistance from the black-oxide finish, extending service life in harsh industrial environments.
• High-strength durability provided by alloy steel and Rockwell C45 hardness, resisting wear and deformation under heavy loads.
• Optimized for high-torque installation with a 9/16" hex drive, ensuring secure engagement and easy assembly with standard tools.
• Effective component positioning due to the cup tip design, which bites into shafts for a secure, non-slip grip.
• Reliable coarse threading (1"-8 UNC) for quicker installation and robust performance in a wide range of materials.
• Versatile headless design allowing for flush mounting in space-constrained assemblies without protruding parts.

Professional Applications & Engineering Value

This black-oxide alloy steel set screw is engineered to solve critical challenges in industrial machinery, automotive, and heavy equipment applications. The Class 3A thread fit and coarse UNC thread provide superior resistance to loosening under vibration, a common failure point in dynamic systems. The headless design with hex drive enables secure, recessed fastening in pulleys, gears, and collars, preventing interference in rotating assemblies. Combined with the cup tip, it ensures positive locking on shafts, maintaining alignment and torque transmission. The black-oxide surface treatment offers an added layer of protection against rust and corrosion, reducing maintenance needs and extending component life in exposed or humid conditions, making it a reliable choice for OEMs and MRO professionals.

Specification Summary & Compliance

This set screw adheres to ASME B18.3 and ASTM F912 specifications, ensuring dimensional accuracy and mechanical performance. The 1"-8 UNC coarse threads are manufactured to Class 3A tolerance for a precise, secure fit. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming the absence of restricted hazardous substances and supporting environmentally responsible sourcing and usage in global markets.