S-91251A415 6-40 x 1 1/4" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 psi provides reliable performance in high-stress applications, reducing the risk of fastener failure
• Precision Class 3A thread fit ensures superior engagement and vibration resistance in demanding industrial environments
• Black-oxide coating on alloy steel offers enhanced corrosion resistance for extended service life in various operating conditions
• Rockwell C37 hardness rating maintains dimensional stability and prevents deformation under heavy loads
• Partially threaded design with UNF fine threads allows for optimal clamping force distribution and secure fastening
• 7/64" hex drive socket head enables easy installation and removal with standard tools while preventing stripping
• Comprehensive compliance with ASTM A574, RoHS 3, and REACH ensures material quality and environmental responsibility

Professional Applications & Engineering Value

This 6-40 UNF Socket Head Cap Screw delivers exceptional engineering value through its black-oxide alloy steel construction and precision Class 3A thread fit. The combination of 170,000 psi tensile strength and Rockwell C37 hardness addresses critical industrial challenges including vibration loosening, material fatigue, and mechanical stress in heavy machinery, automotive assemblies, and precision equipment. The UNF fine thread configuration provides superior holding power in thin materials and applications requiring precise torque control. The partially threaded design allows for optimal load distribution while the black-oxide surface treatment extends service life in moderately corrosive environments, making these socket head cap screws ideal for aerospace, manufacturing, and industrial maintenance applications where reliability and precision are paramount.

Specification Summary & Compliance

This fastener features precision 6-40 UNF threads with Class 3A thread fit for superior dimensional accuracy and consistent performance. Manufactured to ASTM A574 specifications for alloy steel socket head cap screws, ensuring material integrity and mechanical properties. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, confirming its suitability for global industrial applications. Additional specifications include right-hand thread direction, 1-1/4" length with 3/4" minimum thread length, and standard inch system measurements throughout.