S-90275A544 1/4"-20 x 1 1/4" ASME B18.6.3 Steel Slotted Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc-plated steel construction, extending service life in demanding environments
• High tensile strength of 60,000 psi ensures reliable fastening under substantial mechanical loads
• Rockwell B70 hardness provides excellent wear resistance and durability for repeated use
• Class 2A thread fit offers smooth assembly and consistent engagement with standard UNC nuts and tapped holes
• 82° countersink angle allows for flush mounting, reducing snag hazards and improving aesthetics
• Fully threaded design maximizes grip length and load distribution across the entire fastener
• Slotted drive compatibility enables quick installation with common hand tools in maintenance and repair applications

Professional Applications & Engineering Value

This zinc-plated steel flat head screw delivers exceptional performance in industrial settings where vibration resistance and corrosion protection are critical. The UNC coarse threading and Class 2A fit prevent cross-threading during high-speed assembly, while the 82° countersink ensures secure, flush seating in machinery, electrical enclosures, and structural frameworks. Engineered with 60,000 psi tensile strength, it maintains clamp force in dynamic load conditions, making it ideal for automotive, manufacturing, and construction applications where reliability is non-negotiable. The slotted drive simplifies field servicing without specialized tools.

Specification Summary & Compliance

Manufactured to ASME B18.6.3 specifications with UNC coarse threads and Class 2A dimensional tolerance for consistent interchangeability. Fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use in regulated industries. Thread size: 1/4"-20, length: 1-1/4", with right-hand threading and standard flat head profile.