S-90275A543 1/4"-20 x 1 1/8" ASME B18.6.3 Steel Slotted Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc-plated steel construction, ensuring long-lasting performance in demanding industrial environments.
• High tensile strength of 60,000 psi provides reliable load-bearing capacity, reducing the risk of fastener failure under stress.
• Class 2A thread fit offers consistent assembly and easy installation, minimizing production delays and rework.
• UNC coarse threading enables quick engagement and secure fastening, ideal for applications requiring rapid assembly.
• 82° countersink angle with standard flat head profile allows for a flush, professional finish, enhancing both safety and aesthetics.
• Full threading along the 1 1/8" length ensures maximum grip and uniform stress distribution across the entire fastener.
• Rockwell B70 hardness delivers excellent wear resistance, maintaining thread integrity through repeated use.

Professional Applications & Engineering Value

This zinc-plated steel flat head screw is engineered to address common industrial challenges such as vibration loosening and environmental corrosion. The UNC coarse thread design provides superior holding power in softer materials and faster installation, reducing labor time in high-volume assembly lines. With a Class 2A thread fit, it ensures precise alignment and reliable performance in machinery, automotive, and construction applications. The slotted drive offers compatibility with standard tools, while the 82° countersink angle creates a smooth, recessed finish that prevents snagging and improves workplace safety. Ideal for securing metal panels, electrical enclosures, and structural components, this screw combines durability with regulatory compliance to meet rigorous industry demands.

Specification Summary & Compliance

This product adheres to ASME B18.6.3 specifications, ensuring dimensional accuracy and performance reliability. The UNC coarse thread with Class 2A fit provides consistent threading tolerances for secure fastening. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, guaranteeing the use of safe, environmentally responsible materials. Additional features include a right-hand thread direction, standard flat head profile, and 1 1/8" length with full threading for versatile application across industrial sectors.