S-94173A345 1/2"-20 x 4" 12-Point Screws

Key Features & Benefits at a Glance

• Exceptional torque transmission with external 12-point drive for reliable installation in high-stress applications
• Superior corrosion resistance thanks to black-oxide coating on alloy steel for extended service life
• Precise thread engagement with Class 2A UNF fine threads ensuring secure fastening and vibration resistance
• Enhanced load distribution through integrated flange design eliminating the need for separate washers
• Outstanding mechanical strength with 170,000 PSI tensile strength and Rockwell C38 hardness for heavy-duty use
• Optimized partial threading providing maximum grip length while reducing unnecessary thread contact
• Industry-standard compatibility with right-hand UNF fine threading for seamless integration into existing assemblies

Professional Applications & Engineering Value

This 12-point flange screw delivers critical performance advantages in demanding industrial environments where vibration resistance and high torque requirements are paramount. The black-oxide alloy steel construction provides superior corrosion protection while maintaining the material's inherent strength characteristics. The external 12-point drive system ensures maximum torque application without stripping, making it ideal for heavy machinery, structural assemblies, and automotive applications where access may be limited. The UNF fine threading with Class 2A fit offers precise tolerance control, preventing loosening under dynamic loads while the integrated flange distributes clamping force evenly across joined surfaces. This combination of features addresses common failure points in high-vibration environments, providing engineers with a reliable heavy-duty fastener solution that withstands extreme mechanical stresses.

Specification Summary & Compliance

Manufactured to precise dimensional standards with Class 2A thread fit tolerance ensuring consistent performance across applications. The screw features 1/2"-20 UNF fine threading with right-hand direction and partial threading configuration. Complies with industry standards for alloy steel fasteners and meets mechanical property requirements including 170,000 PSI tensile strength and Rockwell C38 hardness. The black-oxide surface treatment provides corrosion resistance while maintaining dimensional integrity. Suitable for applications requiring compliance with ASME and other industrial fastener specifications.