S-91857A842 4-40 x 1/4" ASME B18.6.3 Stainless Steel Round Head Slotted Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance in harsh environments due to 316 Stainless Steel construction and passivated surface treatment.
• High mechanical strength and durability with a tensile strength of 100,000 psi and Rockwell B100 hardness for reliable performance under stress.
• Easy manual installation and removal with a standard slotted drive and rounded head design.
• Wide compatibility and secure fastening thanks to 4-40 UNC coarse threading and Class 2A thread fit.
• Full-length threading ensures maximum grip and uniform load distribution along the entire 1/4" length.
• Compliance with major industry standards including ASME B18.6.3, RoHS 3, and REACH for safe, regulated use.
• Right-hand thread direction provides standard, intuitive tightening for common industrial applications.

Professional Applications & Engineering Value

This 4-40 UNC rounded head slotted screw in 316 Stainless Steel is engineered to address critical challenges in corrosive and high-stress environments. The passivated finish enhances its natural resistance to chemicals, saltwater, and extreme temperatures, making it ideal for marine, chemical processing, and food industry applications. Its coarse threading (UNC) and Class 2A thread fit ensure quick assembly and reliable holding power, reducing installation time and preventing loosening under vibration. The rounded head with slotted drive allows for easy manual adjustment in tight spaces, providing a practical solution for maintenance and equipment where power tools are not feasible. With a tensile strength of 100,000 psi and full threading, it delivers consistent performance in fastening components that require both strength and corrosion resistance, minimizing downtime and replacement costs.

Specification Summary & Compliance

This screw adheres to precise dimensional standards with Class 2A thread fit and UNC coarse threading (4-40 size), ensuring interchangeability and reliable performance. It is manufactured in compliance with ASME B18.6.3 specifications for slotted head screws, guaranteeing consistent quality and engineering accuracy. Additionally, it meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulatory requirements, confirming its safety for use in products without hazardous substances.