S-91440A621 4-40 x 1/4" ASME B18.6.3 Steel Round Head Combination Phillips/Slotted Screws
Steel Round Head Combination Phillips/Slotted 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 zinc-plated steel construction for extended service life in demanding environments
- Exceptional thread engagement with Class 2A thread fit ensuring reliable fastening and vibration resistance
- Enhanced durability from Rockwell B70 hardness providing consistent performance under mechanical stress
- Versatile installation options with combined Phillips/Slotted drive for flexible tool compatibility
- Optimized load distribution through rounded head design that minimizes surface damage
- Maximum holding power with fully threaded 4-40 UNC coarse threads for superior grip in various materials
- Regulatory compliance assurance meeting ASME B18.6.3 standards and environmental regulations
Professional Applications & Engineering Value
These zinc-plated steel rounded head screws deliver critical performance advantages in industrial settings where corrosion resistance and mechanical reliability are paramount. The 4-40 UNC coarse thread configuration provides excellent pull-out resistance in metals, plastics, and composite materials, while the Class 2A thread fit ensures consistent engagement without binding. The dual Phillips/Slotted drive system offers installation flexibility for both automated assembly and field maintenance applications. The rounded head profile distributes clamping force evenly, preventing surface damage to sensitive components. These characteristics make these fully threaded screws ideal for electronics enclosures, machinery assemblies, and automotive components where vibration resistance and long-term reliability are essential.
Specification Summary & Compliance
Manufactured to precise dimensional standards with Class 2A thread fit tolerance and UNC thread form ensuring interchangeability and reliable performance. These screws conform to ASME B18.6.3 specifications for dimensional accuracy and mechanical properties. Environmental compliance includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) requirements, making them suitable for global industrial applications with strict regulatory mandates.
