S-91375A741 4-40 x 3/8" ASME B18.3, ASTM F912 Set Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance through zinc plating, extending service life in demanding industrial environments
• Exceptional holding power with Class 3A thread fit ensuring precise, vibration-resistant connections
• Optimized torque transmission via 0.050" hex drive design preventing tool slippage and fastener damage
• Enhanced material strength with Rockwell C45 hardness maintaining dimensional stability under heavy loads
• Secure component positioning using cup tip design that bites into shafts without causing damage
• Reliable coarse threading (UNC) enabling quick assembly and disassembly in maintenance applications
• Full regulatory compliance meeting ASME B18.3, RoHS 3, and REACH standards for global industrial use

Professional Applications & Engineering Value

This 4-40 UNC set screw delivers critical engineering solutions for precision machinery and industrial equipment requiring secure component positioning. The zinc plated alloy steel construction provides essential corrosion protection in manufacturing environments, while the Rockwell C45 hardness ensures the fastener maintains its structural integrity under repetitive stress and vibration. The headless design with hex drive allows for flush mounting in confined spaces, making it ideal for securing pulleys, gears, and collars on shafts where protruding fasteners would interfere with operation. The cup tip configuration creates positive engagement with shaft materials without causing significant surface damage, enabling reliable torque transmission while preserving the integrity of expensive components. These industrial set screws are engineered to prevent loosening in high-vibration applications, reducing maintenance downtime and equipment failure risks.

Specification Summary & Compliance

Manufactured to exacting Class 3A thread fit tolerances with 4-40 UNC coarse threads and right-hand thread direction. The 3/8" length provides optimal engagement depth for secure fastening applications. Compliant with ASME B18.3 dimensional specifications where applicable per ASTM F912, ensuring interchangeability and reliability. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations for hazardous substance restrictions, making these set screws suitable for global industrial distribution and use.