S-91858A546 1/4"-20 x 1 1/2" ASME B18.6.3 Stainless Steel Slotted Flat Head Screws

Key Features & Benefits at a Glance

• Maximum corrosion resistance with 316 stainless steel construction and passivated finish, ideal for harsh chemical and marine environments
• Superior mechanical strength with 70,000 psi tensile strength and Rockwell B80 hardness for reliable performance under heavy loads
• Precision thread engagement through Class 2A UNC coarse threading ensures secure fastening and vibration resistance
• Flush mounting capability with standard 82° countersink angle and flat head design for smooth surface applications
• Full-length threading provides maximum grip strength and uniform load distribution along the entire fastener length
• Industry-standard compliance with ASME B18.6.3 specifications guarantees dimensional accuracy and interchangeability
• Environmental regulation compliance with RoHS 3 and REACH ensures safe use in regulated industrial applications

Professional Applications & Engineering Value

This 316 stainless steel flat head screw delivers exceptional engineering value in demanding applications where corrosion resistance and structural integrity are paramount. The combination of marine-grade 316 stainless steel and passivated surface treatment creates a robust barrier against chloride-induced stress corrosion cracking, making it ideal for chemical processing equipment, marine hardware, and food processing machinery. The UNC coarse threading with Class 2A fit provides rapid installation and reliable performance in high-vibration environments, while the flat head design with 82° countersink ensures flush mounting in precision assemblies. With full threading along the 1½" length, engineers benefit from maximum thread engagement and uniform stress distribution, preventing premature failure in structural applications.

Specification Summary & Compliance

This fastener maintains precise Class 2A thread fit tolerances per UNC standards with 1/4"-20 coarse threading and right-hand orientation. Manufacturing complies with ASME B18.6.3 specifications for dimensional accuracy, including head diameter (0.477"), head height (0.153"), and 82° countersink angle. The screw meets RoHS 3 (2015/863/EU) compliance for restricted substances and REACH (EC 1907/2006) regulations for chemical safety, ensuring suitability for regulated industrial and commercial applications worldwide.