S-91858A844 4-40 x 1/4" ASME B18.6.3 Stainless Steel Slotted Flat Head Screws
Stainless Steel Slotted Flat Head 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
- Exceptional corrosion resistance thanks to 316 stainless steel construction and passivated finish, ideal for harsh industrial environments.
- High-strength reliability with a 70,000 psi tensile strength and Rockwell B80 hardness for demanding applications.
- Precise and secure fastening ensured by the Class 2A thread fit and coarse UNC threads for easier assembly and vibration resistance.
- Flush, low-profile installation with a standard flat head and 82° countersink angle for a smooth, finished surface.
- Broad industrial compliance meeting ASME B18.6.3 specifications, RoHS 3, and REACH regulations for safe, global use.
- Versatile and fully threaded 1/4" length provides maximum grip and holding power across the entire shank.
- Simple and tool-accessible drive with a standard slotted head for easy installation and removal with common tools.
Professional Applications & Engineering Value
This 4-40 UNC flat head screw is engineered to solve critical fastening challenges in demanding sectors. The core value lies in its 316 stainless steel material and passivated finish, which work synergistically to provide superior corrosion resistance against chemicals, saltwater, and industrial atmospheres. This makes it an indispensable component in marine equipment, chemical processing plants, and food-grade machinery where material integrity is paramount. The combination of coarse UNC threading and a Class 2A fit ensures rapid assembly with reliable tolerance, reducing the risk of cross-threading and maintaining joint integrity under vibration. The fully threaded design and 82° countersink allow for a secure, flush mount in pre-drilled holes, preventing snagging and providing a clean aesthetic for panels, enclosures, and precision assemblies.
Specification Summary & Compliance
This fastener adheres to precise dimensional standards, including a Class 2A thread fit for consistent interchangeability. It is manufactured in compliance with the ASME B18.6.3 standard, ensuring mechanical and dimensional reliability. The product is also confirmed to be RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting stringent environmental and safety regulations for hazardous substances.
