S-91255A110 4-40 x 1/2" ASTM F835 Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with black-oxide coating, ideal for harsh industrial environments
• High tensile strength of 120,000 psi ensures reliable performance under heavy loads
• Precise Class 3A thread fit provides superior engagement and vibration resistance
• Rockwell C39 hardness delivers excellent wear resistance and long service life
• Compact 1/16" hex drive allows easy installation in tight spaces with standard tools
• Fully threaded 1/2" length offers maximum grip and adjustment flexibility
• Compliant with major industry standards including ASME B18.3 and ASTM F835 for guaranteed quality

Professional Applications & Engineering Value

These 4-40 UNC thread screws with black-oxide alloy steel construction address critical industrial fastening challenges. The rounded button head profile and coarse thread spacing provide superior clamping force in applications where vibration resistance is essential, such as machinery assembly, electronic enclosures, and automotive components. The combination of 120,000 psi tensile strength and Rockwell C39 hardness ensures these hex drive screws maintain integrity under dynamic loads, while the fully threaded design offers complete engagement for maximum holding power. Ideal for precision engineering applications requiring reliable, high-performance industrial fasteners with consistent quality.

Specification Summary & Compliance

This 1/2" rounded head screw features precise Class 3A thread fit with UNC coarse threading and right-hand thread direction. Manufactured to ASME B18.3 and ASTM F835 specifications, ensuring dimensional accuracy and performance reliability. Fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations for safe industrial use worldwide.