S-91035A750 1/4"-28 x 7/8" ASTM A581, ASTM A582 Captive Panel Screws

Key Features & Benefits at a Glance

• Enhanced manual grip with knurled head texture for secure handling without tools in tight spaces
• Superior corrosion resistance from 18-8 stainless steel construction, ideal for humid or demanding industrial environments
• Precise fine thread engagement with 1/4"-28 UNF Class 2A threads ensuring reliable, vibration-resistant fastening in panels
• Optimized partial threading design allows smooth insertion and secure captive retention in panel assemblies
• Compliance with ASTM A581 standards guarantees consistent material quality and mechanical performance
• Eco-friendly manufacturing meeting RoHS 3 and REACH regulations for safe use in electronic and consumer goods
• Right-hand thread direction provides intuitive installation for standard assembly procedures

Professional Applications & Engineering Value

This knurled thumb screw in 18-8 stainless steel solves critical challenges in captive panel screw applications, where repeated access and tool-free operation are essential. The fine UNF thread spacing and Class 2A fit deliver exceptional resistance to loosening under vibration, making it ideal for electronics enclosures, instrumentation panels, and machinery covers. The partially threaded shank design prevents cross-threading during installation, while the knurled head ensures a firm grip even with gloved hands. Engineered to ASTM A581 specifications, it offers reliable performance in corrosive or high-use environments, streamlining maintenance and reducing assembly time.

Specification Summary & Compliance

This thumb screw features a 1/4"-28 UNF fine thread with Class 2A tolerance for precise fit, and a partially threaded length of 5/16". It complies with ASTM A581 material standards and is RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliant, ensuring adherence to environmental and safety regulations for industrial and electronic use.