S-90550A230 4-40 x 3/8" ASME B18.3, ASTM F879, MIL-DTL-18240 Venting Stainless Steel Hex-Drive Flat Head Screws
Venting Stainless Steel Hex-Drive 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
- Superior corrosion resistance with 18-8 Stainless Steel construction, ideal for harsh environments and long-term reliability.
- Precise, secure fastening ensured by Class 3A thread fit, minimizing the risk of loosening under vibration.
- Efficient installation and removal with a 1/16" hex drive, providing a positive grip and reducing tool slippage.
- Prevents pressure buildup thanks to the vented feature (0.035" vent diameter), crucial for sealed assemblies.
- Flush, professional finish achieved with the standard 82° countersink angle on the flat head.
- Robust thread engagement from the fully threaded, coarse (UNC) design, offering strong holding power.
- Guaranteed quality and interchangeability through compliance with major standards like ASME B18.3, ASTM F879, and MIL-DTL-18240.
Professional Applications & Engineering Value
This 4-40 UNC Flat Head Screw is engineered to solve critical challenges in precision assembly. The 18-8 Stainless Steel material provides excellent resistance to oxidation and corrosion, making it a reliable choice for industrial equipment, electronics, and applications exposed to moisture or chemicals. The combination of a hex drive and fully threaded coarse (UNC) body allows for high torque application and rapid installation, reducing assembly time. The integrated vent is a key feature for pressure-sensitive environments, preventing vacuum or pressure lock during fastening. Its compliance with stringent standards ensures it meets the demands of military (MIL-DTL-18240) and commercial specifications, delivering consistent performance and reliability for engineers and procurement specialists.
Specification Summary & Compliance
This screw features a 4-40 UNC coarse thread with a Class 3A fit for high precision, a length of 3/8", and a 1/16" hex drive. The flat head has an 82° countersink angle and a 0.035" vent diameter. It is manufactured in accordance with ASME B18.3, ASTM F879, and MIL-DTL-18240 specifications. The product is also RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, ensuring it is free of hazardous substances and safe for use in regulated markets.
