S-95198A133 4-40 x 7/8" ASME B18.3, DIN 912, ISO 4762 Sealing Socket Head Screws

Key Features & Benefits at a Glance

• Superior sealing performance with silicone rubber O-ring that maintains integrity under pressures up to 1500 psi, preventing leaks in critical applications
• Exceptional corrosion resistance thanks to 18-8 stainless steel construction, ensuring long-term reliability in harsh environments
• Precise thread engagement with Class 3A fit for secure fastening and vibration resistance in demanding assemblies
• Wide temperature compatibility from -80° to 400°F due to silicone O-ring material, suitable for extreme thermal cycling conditions
• High strength-to-weight ratio with 100,000 psi tensile strength and Rockwell B85 hardness for durable, reliable performance
• Industry-standard compatibility with hex drive design meeting ASME B18.3, DIN 912, and ISO 4762 specifications
• Environmental compliance assurance with RoHS 3 and REACH compliance for global supply chain integration

Professional Applications & Engineering Value

This 4-40 UNC thread socket head cap screw delivers critical sealing solutions for industrial equipment, hydraulic systems, and precision machinery where fluid containment is paramount. The 18-8 stainless steel construction combined with the silicone rubber O-ring creates a robust barrier against leaks, even under fluctuating pressure and temperature conditions. Engineers specify this fastener for applications requiring both high tensile strength (100,000 psi) and reliable sealing up to 1500 psi, making it ideal for pump housings, valve assemblies, and compressed air systems. The Class 3A thread fit ensures precise engagement in tapped holes, while the fully threaded design provides consistent clamping force along the entire 7/8" length. This combination of material properties and precision manufacturing addresses common challenges of seal degradation, corrosion-induced failure, and assembly inconsistency in industrial settings.

Specification Summary & Compliance

This socket head cap screw features 4-40 UNC coarse threads with Class 3A precision fit for superior thread engagement. Manufacturing complies with ASME B18.3, DIN 912, and ISO 4762 standards, ensuring dimensional accuracy and interchangeability. The product is fully RoHS 3 (2015/863/EU) compliant and REACH (EC 1907/2006) compliant, meeting current environmental regulations for hazardous substance restrictions. Thread spacing follows coarse thread specifications with right-hand orientation, while the hex drive accepts standard 3/32" tools for consistent installation torque.