S-91255A074 2-56 x 1/8" ASTM F835 Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with black-oxide coating for extended service life in demanding industrial environments
• Exceptional tensile strength of 120,000 psi ensures reliable performance under high-stress applications
• Precision Class 3A thread fit provides superior engagement and vibration resistance in critical assemblies
• Rockwell C39 hardness rating delivers excellent wear resistance and durability for repeated use
• Hex drive design (0.050") allows for secure tool engagement and efficient installation in confined spaces
• Fully threaded construction ensures maximum holding power along the entire fastener length
• Compliant with major industry standards including ASME B18.3 and ASTM F835 for guaranteed quality and interoperability

Professional Applications & Engineering Value

These 2-56 UNC thread rounded head hex drive screws deliver exceptional engineering value in precision assembly applications where reliability is paramount. The black-oxide alloy steel construction provides superior corrosion resistance, making them ideal for electronics, aerospace components, and industrial machinery exposed to harsh operating conditions. The Class 3A thread fit ensures precise mating with nuts and threaded holes, eliminating play and reducing vibration-induced loosening. The button head profile offers a low-profile design that clears obstructions while the hex drive provides positive torque transmission without cam-out. These characteristics make them particularly valuable in applications requiring repeated disassembly and reassembly, where coarse thread spacing facilitates quick installation and the fully threaded design maintains consistent clamping force across the entire engagement length.

Specification Summary & Compliance

Manufactured to exacting Class 3A thread fit tolerances with UNC coarse thread spacing and right-hand thread direction. These screws conform to ASME B18.3 and ASTM F835 manufacturing specifications, ensuring dimensional accuracy and mechanical performance. Environmental compliance includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) requirements, making them suitable for regulated industries and international markets. The black-oxide surface treatment provides consistent corrosion protection while maintaining the 120,000 psi tensile strength and Rockwell C39 hardness of the underlying alloy steel material.