S-91253A544 1/4"-20 x 1 1/4" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional Tensile Strength – With 130,000 psi tensile strength, these screws provide reliable, high-load fastening for demanding industrial applications.
• Superior Corrosion Resistance – The black-oxide finish on alloy steel offers enhanced protection against rust and environmental wear, extending service life.
• Precise Thread Fit – Class 3A thread fit ensures tight, secure connections with minimal risk of loosening under vibration or stress.
• Easy Installation & Removal – Hex drive design (5/32" drive size) allows for quick, tool-friendly assembly and disassembly in confined spaces.
• Optimized Head Design – Standard 82° flat head profile enables flush mounting, reducing snagging and improving aesthetic integration.
• Full Thread Engagement – Fully threaded UNC coarse threads provide maximum grip and distribution of clamping force along the entire length.
• High Hardness & Durability – Rockwell C39 hardness ensures the screw maintains its form and function under repetitive or high-torque use.

Professional Applications & Engineering Value

Engineered for high-stress industrial environments, these 1/4"-20 UNC flat head hex screws address critical fastening challenges where vibration resistance and corrosion protection are paramount. The black-oxide alloy steel construction, combined with a Class 3A thread fit, prevents premature failure in machinery, automotive assemblies, and structural frameworks. The fully threaded coarse spacing ensures rapid installation and robust holding power, while the 82° countersink angle allows for seamless surface integration. Ideal for OEM and MRO applications, these screws deliver consistent performance under dynamic loads, reducing maintenance cycles and enhancing operational reliability.

Specification Summary & Compliance

This screw meets Class 3A thread tolerance for precision fit and is manufactured in accordance with ASME B18.3 and ASTM F835 specifications. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental standards, ensuring safe use in regulated industries. Dimensions include a 1/4"-20 UNC coarse thread, 1-1/4" length, and 0.531" head diameter, providing exacting consistency for professional fastener requirements.