S-91306A256 5-40 x 1/4" ASTM F835 Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc plating, extending service life in harsh industrial environments
• Exceptional tensile strength of 120,000 psi ensures reliable performance under heavy loads and vibration
• Precise Class 3A thread fit provides secure fastening with reduced risk of cross-threading or loosening
• Rockwell C39 hardness maintains structural integrity and resists wear during repeated installations
• Hex drive design (5/64") allows for high-torque application and easy installation in confined spaces
• Coarse UNC threading enables quick assembly and superior grip in various materials
• Full threading along 1/4" length offers maximum engagement and holding power

Professional Applications & Engineering Value

These zinc-plated alloy steel rounded head screws with 5-40 UNC coarse threading deliver critical performance advantages for industrial assemblies. The Class 3A thread fit ensures precise engagement, eliminating play in machinery components while the button head profile provides a low-profile finish that won't snag on equipment. Engineered with 120,000 psi tensile strength and Rockwell C39 hardness, they withstand extreme mechanical stress in automotive, electronics, and heavy equipment applications. The zinc plating creates a protective barrier against corrosion, making these fully threaded screws ideal for outdoor enclosures, structural frames, and manufacturing fixtures where reliability is paramount.

Specification Summary & Compliance

Manufactured to exacting Class 3A thread tolerances with UNC coarse thread form and 5-40 thread size. Complies with ASME B18.3 and ASTM F835 manufacturing specifications. Meets environmental standards including RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance for hazardous substance restrictions.