S-90287A546 1/4"-20 x 1 1/2" ASME B18.6.3 Tamper-Resistant One-Way-Drive Steel Round Head Screws

Key Features & Benefits at a Glance

• Enhanced Corrosion Resistance: Zinc-plated steel construction provides reliable protection against rust and environmental degradation in demanding industrial settings.
• Superior Tensile Strength: With a 60,000 PSI tensile strength, this screw offers exceptional load-bearing capacity for heavy-duty assemblies and structural applications.
• Optimized Thread Engagement: UNC coarse threading ensures faster installation and reduced cross-threading risk, ideal for quick assembly operations.
• Precision Thread Fit: Class 2A fit guarantees consistent, reliable fastening with standard nuts and tapped holes, minimizing assembly inconsistencies.
• High Durability: Rockwell B70 hardness provides excellent resistance to wear and deformation, extending the screw's service life under vibration and stress.
• Secure One-Way Drive: The one-way drive style offers tamper-resistant installation, enhancing security in public or restricted-access applications.
• Full Thread Coverage: Fully threaded design maximizes grip length and pull-out resistance across the entire shank for superior holding power.

Professional Applications & Engineering Value

This zinc-plated steel rounded head screw is engineered to address critical challenges in industrial assembly, including vibration loosening, corrosion-induced failure, and installation inefficiency. The UNC coarse thread profile enables rapid installation in sheet metal, machinery, and structural frameworks, reducing labor time while the Class 2A fit ensures consistent clamping force. The zinc plating acts as a sacrificial layer, protecting the core material in humid or chemically aggressive environments like outdoor equipment and manufacturing plants. With a 60,000 PSI tensile strength and Rockwell B70 hardness, it maintains integrity under dynamic loads, making it suitable for conveyor systems, automotive components, and heavy equipment where reliability is paramount. The fully threaded design and one-way drive further enhance security and versatility across diverse industrial applications.

Specification Summary & Compliance

This screw adheres to ASME B18.6.3 specifications for dimensional accuracy and mechanical properties, with a Class 2A thread fit ensuring interchangeability with standard components. It is manufactured in the inch system with a 1/4"-20 UNC coarse thread and 1-1/2" length. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming the absence of restricted hazardous substances for safe use in global markets.