S-90429A166 1/2"-20 x 6 1/2" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Superior load-bearing capability with 130,000 psi tensile strength for demanding applications
• Enhanced thread engagement and vibration resistance through Class 3A fit and UNF fine threading
• Exceptional wear resistance due to Rockwell C39 hardness for extended service life
• Secure flush mounting with standard 82° countersink angle and flat head design
• Reliable installation torque enabled by 5/16" hex drive for precise fastening control
• Optimized weight-to-strength ratio through partial threading in critical stress areas
• Full regulatory compliance meeting ASTM F835, RoHS 3, and REACH standards

Professional Applications & Engineering Value

These alloy steel flat head screws deliver critical performance in heavy machinery, structural assemblies, and precision equipment where vibration resistance and high tensile strength are paramount. The UNF fine threading with Class 3A fit ensures superior thread engagement in tapped holes, reducing loosening under dynamic loads. The 82° countersink angle provides seamless flush mounting in precision-machined surfaces, while the partial threading design concentrates strength where needed most. Manufactured to ASTM F835 specifications, these screws maintain dimensional stability in high-stress industrial environments, making them ideal for automotive, construction, and manufacturing applications requiring reliable inch system fasteners.

Specification Summary & Compliance

This 1/2"-20 UNF flat head screw features precision Class 3A thread fit per Unified Thread Standard with 6 1/2" length and partial threading (minimum 1 3/4" thread length). Manufacturing complies with ASTM F835 specifications for alloy steel fasteners, with full compliance to RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations. The inch system measurement ensures compatibility with North American industrial standards and equipment specifications.