S-90046A125 1/4"-28 x 1 1/4" NAS1801-4-20 High-Strength Steel Hex Head Screws with Phillips Drive

Key Features & Benefits at a Glance

• Superior corrosion resistance from cadmium plating, extending service life in harsh industrial environments
• Exceptional thread precision with Class 3A fit for reliable, vibration-resistant assemblies in critical applications
• High-strength performance with 160,000 psi tensile strength and Rockwell C34 hardness for heavy-duty fastening requirements
• Optimized drive engagement through combined external hex/Phillips No. 3 drive, preventing stripping during high-torque installation
• Controlled thread engagement via partially threaded design, reducing stress concentration and improving joint integrity
• Regulatory compliance assurance meeting NAS1801-4-20 specifications while being RoHS 3 and REACH compliant
• Fine thread advantage with UNF 1/4"-28 providing enhanced adjustment precision and superior clamping force distribution

Professional Applications & Engineering Value

This 1/4"-28 UNF Class 3A hex head screw delivers critical engineering solutions where vibration resistance, precision fit, and environmental durability are paramount. The cadmium plated steel construction provides exceptional corrosion protection for aerospace, defense, and heavy machinery applications where exposure to harsh elements is common. The partially threaded design ensures optimal stress distribution while the fine thread spacing maintains clamping force under dynamic loads. With dual external hex/Phillips drive compatibility, installers achieve secure fastening without tool slippage, making these industrial hex screws ideal for maintenance-critical assemblies requiring repeated access. The combination of 160,000 psi tensile strength and Rockwell C34 hardness guarantees performance in high-stress applications while meeting stringent NAS1801-4-20 specifications.

Specification Summary & Compliance

Manufactured to precise Class 3A thread fit tolerances with UNF 1/4"-28 fine threads in right-hand direction. The partially threaded configuration provides 1-3/16" minimum thread length on a 1-1/4" overall length. Compliant with NAS1801-4-20 manufacturing specifications and certified RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental standards. Manufactured in inch system with external hex/Phillips No. 3 drive, 3/8" head width, and 1/4" head height dimensions.