S-91870A772 1/4"-20 x 1 1/2" ASME B18.3 Tamper-Resistant Torx Steel Flat Head Screws

Key Features & Benefits at a Glance

• Superior tamper resistance with T30 Torx drive design to prevent unauthorized access in secure installations
• Enhanced corrosion protection through black oxide finish, extending service life in demanding environments
• Exceptional load-bearing capacity with 160,000 psi tensile strength for high-stress applications
• Precision thread engagement through Class 3A thread fit ensuring reliable fastening in critical assemblies
• Optimized flush mounting with 82° countersink angle and flat head design for smooth surface finishes
• Maximum material durability from alloy steel construction with Rockwell C38 hardness rating
• Full-thread coverage along the 1-1/2" length for consistent holding power across the entire fastener

Professional Applications & Engineering Value

These black oxide alloy steel flat head screws deliver critical performance where security, strength, and corrosion resistance intersect. The tamper-resistant T30 Torx drive prevents unauthorized disassembly in public fixtures, industrial machinery, and electronic enclosures, while the Class 3A UNC coarse threads provide superior engagement in both metals and plastics. The 82° countersink angle ensures flush mounting in precision applications, eliminating protrusions that could interfere with moving components. With 160,000 psi tensile strength, these fasteners maintain integrity under vibration and dynamic loads common in manufacturing equipment, automotive assemblies, and structural frameworks. The black oxide finish creates a protective barrier against moisture and chemicals, making these screws ideal for outdoor applications and harsh industrial environments where corrosion would compromise fastener performance.

Specification Summary & Compliance

Manufactured to exacting ASME B18.3 specifications with Class 3A thread fit for precision tolerance in demanding applications. Features 1/4"-20 UNC coarse threads with right-hand orientation and full threading along the 1-1/2" length. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental standards, ensuring safe use across global markets. The 82° flat head profile meets industry-standard countersink requirements for seamless integration into various materials and applications.