S-98164A063 4-40 x 3/8" ASME B18.3 Stainless Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 316 stainless steel construction, ideal for harsh chemical and marine environments
• Enhanced thread engagement and vibration resistance due to Class 3A thread fit and coarse UNC threading
• High mechanical strength with 70,000 psi tensile strength and Rockwell B55 hardness for demanding applications
• Secure, slip-resistant installation enabled by the hex drive design with 1/16" drive size
• Complete thread coverage along the 3/8" length ensures maximum holding power and load distribution
• Extended service life through passivated surface finish that increases corrosion protection
• Regulatory compliance assurance meeting ASME B18.3 standards and environmental regulations including RoHS 3 and REACH

Professional Applications & Engineering Value

These 4-40 UNC threaded 316 stainless steel rounded head screws deliver exceptional performance in challenging industrial settings where corrosion resistance and mechanical reliability are paramount. The combination of Class 3A thread fit and coarse threading provides superior vibration resistance in equipment subjected to constant motion or thermal cycling. The passivated finish significantly enhances the inherent corrosion resistance of 316 stainless steel, making these fasteners ideal for chemical processing, marine equipment, and food processing applications where exposure to moisture and aggressive substances is common. The hex drive design ensures secure installation without cam-out, while the fully threaded configuration maximizes grip length in thin materials and confined spaces. These screws solve critical fastening challenges in OEM manufacturing, maintenance operations, and precision assembly where failure is not an option.

Specification Summary & Compliance

These rounded head screws feature precision 4-40 UNC coarse threads with Class 3A fit for tight tolerance applications. Manufacturing complies with ASME B18.3 specifications ensuring dimensional accuracy and interchangeability. The fasteners are fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, containing no restricted substances above threshold limits. The 316 stainless steel material provides excellent corrosion resistance, while the passivated finish further enhances surface protection without compromising dimensional integrity.