S-91773A108 4-40 x 3/8" ASME B18.6.3 Stainless Steel Round Head Phillips Screws
Stainless Steel Round Head Phillips Screws
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Basic Information
Head Parameters
Dimensions
Thread Parameters
Tip & Drive Parameters
Material & Strength
Temperature & Environment
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Key Features & Benefits at a Glance
- Superior corrosion resistance with 18-8 stainless steel and passivated finish, ideal for harsh environments and extended service life.
- Exceptional mechanical strength offering 100,000 psi tensile strength and Rockwell B100 hardness for reliable load-bearing in demanding applications.
- Precision thread engagement with Class 2A fit and coarse UNC threading ensures quick, secure, and vibration-resistant fastening.
- Optimized drive performance featuring a No. 1 Phillips drive and rounded head for efficient installation and reduced cam-out risk.
- Full-threaded design provides consistent clamping force along the entire 3/8" length for maximum joint integrity.
- Industry-standard compliance with ASME B18.6.3 guarantees dimensional accuracy and interchangeability.
- Environmental and safety adherence through RoHS 3 and REACH compliance, ensuring safe use in regulated industries.
Professional Applications & Engineering Value
This 4-40 UNC Rounded Head Phillips Screw is engineered to address critical fastening challenges in industrial settings. The 18-8 Stainless Steel construction, enhanced by a passivated finish, provides outstanding resistance to oxidation and chemical exposure, making it suitable for electronics, machinery, and outdoor equipment where moisture or corrosive agents are present. The coarse thread spacing and Class 2A thread fit enable rapid assembly and secure holding in materials prone to stripping. With a fully threaded right-hand design and high tensile strength, it ensures uniform stress distribution and prevents loosening under dynamic loads, reducing maintenance needs and improving operational reliability in automated systems and precision instruments.
Specification Summary & Compliance
This screw features a 4-40 UNC thread size with Class 2A dimensional tolerance and coarse thread spacing for consistent performance. Manufacturing and quality adhere to ASME B18.6.3 specifications, ensuring precise head diameter (0.211"), head height (0.086"), and thread diameter (0.112"). The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming the absence of restricted substances for safe industrial use.
