S-98625A391 1/4"-100 x 4" Set Screws

Key Features & Benefits at a Glance

• Superior holding power with Class 3A thread fit for reliable, vibration-resistant fastening in critical assemblies.
• Enhanced durability and corrosion resistance provided by 303 Stainless Steel construction, ideal for harsh industrial environments.
• Precise, secure engagement with an ultra-fine 1/4"-100 thread for maximum contact area and minimal risk of loosening.
• Easy and reliable installation using a standard 3/32" hex drive, allowing for high torque application in confined, headless designs.
• Reduced surface damage and improved grip from the alloy steel ball tip, which concentrates force for secure component positioning.
• Long 4" length provides deep penetration and is suitable for applications requiring extended reach through materials.
• Compliance with major environmental regulations including RoHS 3 and REACH, ensuring suitability for global industrial supply chains.

Professional Applications & Engineering Value

This headless hex set screw is engineered to solve critical challenges in precision assembly and motion control systems. The 303 stainless steel body offers excellent resistance to corrosion and wear, which is vital for machinery operating in demanding conditions. The ultra-fine thread (1/4"-100) and Class 3A fit provide a tighter, more precise engagement than standard threads, significantly reducing the risk of backlash and vibrational loosening in high-speed or precision equipment like spindles, gears, and couplings. The inclusion of a hardened alloy steel ball tip ensures minimal marring of the shaft while creating a concentrated point of contact that improves grip and prevents axial movement. This combination of a long 4" shank, fine thread, and robust materials makes it an indispensable industrial fastener for applications where reliability and positional accuracy are non-negotiable.

Specification Summary & Compliance

This set screw features a 1/4"-100 UNS ultra fine thread with a precision Class 3A thread fit for superior dimensional accuracy. It is manufactured from 303 Stainless Steel with a right-hand thread direction and is driven by a 3/32" hex drive. The product is fully compliant with RoHS 3 (2015/863/EU) under exemption 6(c) and is REACH (EC 1907/2006) compliant as of the latest substance list.