S-90288A108 4-40 x 3/8" ASME B18.6.3 Tamper-Resistant One-Way-Drive Stainless Steel Round Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel and passivated finish for long-lasting performance in harsh environments
• Exceptional mechanical strength with 80,000 psi tensile strength and Rockwell B96 hardness for reliable, high-stress applications
• Optimized thread engagement through UNC coarse threading and Class 2A fit ensures secure fastening and vibration resistance
• Tamper-resistant design with one-way drive and rounded head prevents unauthorized disassembly in security-sensitive installations
• Full threading along the 3/8" length provides maximum grip and load distribution across the entire fastener
• Industry-standard compliance with ASME B18.6.3 specifications guarantees dimensional accuracy and interchangeability
• Environmental regulation adherence through RoHS 3 and REACH compliance for sustainable, globally acceptable manufacturing

Professional Applications & Engineering Value

These 4-40 UNC coarse thread rounded head screws deliver critical reliability in demanding industrial settings where corrosion resistance and tamper-proof security are paramount. The combination of 18-8 stainless steel construction and passivated finish creates a protective barrier against chemical exposure and atmospheric corrosion, significantly extending service life in manufacturing equipment, electronic enclosures, and outdoor installations. The one-way drive system provides permanent fastening solutions for public infrastructure, transportation components, and security assemblies where disassembly prevention is essential. With full threading along the entire 3/8" length, these screws maintain consistent clamping force across joined materials, preventing loosening under dynamic loads while the Class 2A thread fit ensures smooth installation without compromising retention strength.

Specification Summary & Compliance

This fastener maintains precise Class 2A thread fit tolerances per UNC coarse thread standards with dimensional compliance to ASME B18.6.3 specifications. The manufacturing process adheres to RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental directives, ensuring hazardous substance restriction compliance. Mechanical properties include 80,000 psi tensile strength and Rockwell B96 hardness with right-hand thread orientation and complete threading along the 3/8" length.