S-91266A546 1/4"-20 x 1 1/2" ASTM F835 Alloy Steel Thread-Locking Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Vibration-resistant locking: Integrated nylon patch thread locker maintains secure fastening in high-vibration environments from -65° to 250°F
• Superior load-bearing capacity: 130,000 psi tensile strength and Rockwell C39 hardness ensure reliable performance under heavy mechanical stress
• Precise thread engagement: Class 3A thread fit provides tighter tolerances for improved fastening accuracy and reduced loosening risk
• Corrosion-resistant protection: Black-oxide coating on alloy steel offers enhanced durability against oxidation and wear in industrial settings
• Optimized installation efficiency: 5/32" hex drive and 82° countersink angle enable flush mounting and straightforward assembly with standard tools
• Industry-standard compatibility: UNC coarse thread pattern ensures broad interchangeability with existing equipment and components
• Regulatory compliance assurance: Meets ASTM F835 specifications while being RoHS 3 and REACH compliant for global industrial applications

Professional Applications & Engineering Value

Engineered for demanding industrial fastening applications, this black-oxide alloy steel flat head screw addresses critical vibration-induced loosening challenges through its nylon patch thread locking technology. The combination of Class 3A thread fit and UNC coarse threading provides exceptional engagement stability in machinery, automotive assemblies, and structural frameworks where thermal cycling and dynamic loads compromise ordinary fasteners. The 82° countersink angle and flat head design create seamless surface finishes while the fully threaded construction distributes clamping force evenly across the entire engagement length. With 130,000 psi tensile strength, this hex drive screw maintains joint integrity in high-stress environments where reliability is non-negotiable.

Specification Summary & Compliance

This 1/4"-20 x 1-1/2" flat head hex screw features precision Class 3A thread fit with UNC coarse thread spacing and right-hand thread direction. Manufactured to ASTM F835 specifications with full compliance to RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations. The black-oxide alloy steel construction delivers consistent performance across the specified -65° to 250°F temperature range while maintaining Rockwell C39 hardness and dimensional stability.