S-91263A553 1/4"-20 x 1/2" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional Tensile Strength - Withstands up to 130,000 psi for reliable performance in high-stress industrial applications.
• Superior Corrosion Resistance - Zinc-plated alloy steel construction ensures long-term durability in harsh environments.
• Precision Thread Fit - Class 3A thread specification provides secure, vibration-resistant fastening with minimal play.
• Optimized Head Design - 82° countersink angle and flat head profile allow for flush mounting and clean surface finishes.
• Enhanced Drive Efficiency - Hex drive (5/32") enables high-torque installation without cam-out issues.
• Full Thread Engagement - Completely threaded 1/2" length ensures maximum holding power across the entire fastener.
• Industry Compliance - Meets ASTM F835 specifications while being RoHS 3 and REACH compliant for global applications.

Professional Applications & Engineering Value

These 1/4"-20 UNC flat head screws deliver critical performance advantages for industrial assembly and machinery applications. The zinc-plated alloy steel construction combined with Rockwell C39 hardness provides exceptional resistance to wear and environmental degradation, making them ideal for automotive components, electrical enclosures, and heavy equipment where corrosion protection is essential. The Class 3A thread fit with coarse thread spacing ensures rapid installation and reliable performance in vibration-prone environments. The 82° countersink angle and flat head design allow for seamless integration into precision-machined surfaces, eliminating protrusions that could interfere with moving parts or aesthetic requirements. These fully threaded screws with hex drive configuration offer superior clamping force distribution and installation efficiency for high-volume production environments.

Specification Summary & Compliance

This 1/4"-20 UNC flat head screw features precision Class 3A thread fit with coarse thread spacing and right-hand threading. Manufactured to ASTM F835 specifications with dimensional accuracy including 0.531" head diameter, 0.161" head height, and 1/2" length. The product maintains full compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and global market acceptance. The inch system measurement and standardized dimensions guarantee interchangeability and reliable performance across industrial applications.