S-90291A583 5/16"-18 ASME B18.3 Set Screws

Key Features & Benefits at a Glance

• Secure Component Locking – The nylon 6/6 plastic tip provides mar-free clamping, protecting expensive shafts and components from surface damage during repeated adjustments.
• Exceptional Corrosion Resistance – 18-8 Stainless Steel construction ensures long-term reliability in humid, chemical, or washdown environments, reducing replacement frequency.
• Precise Thread Engagement – Class 3A thread fit with UNC coarse threads offers tighter tolerances for superior vibration resistance and secure fastening in high-stress assemblies.
• High-Temperature & Chemical Resilience – Nylon tip rated for -50° to 250° F maintains its integrity in fluctuating thermal conditions and resists oils and solvents.
• Optimized Torque Application – 5/32" hex drive in a headless design allows flush installation and enables high torque transfer in confined spaces.
• Enhanced Durability – Rockwell B80 hardness provides excellent resistance to wear and deformation, ensuring the screw retains its mechanical properties over time.
• Regulatory Compliance for Global Supply Chains – Meets ASME B18.3 specifications and is RoHS 3 & REACH compliant, supporting use in regulated industries and international projects.

Professional Applications & Engineering Value

This hex headless set screw is engineered to solve critical challenges in precision assembly and motion control systems. The 18-8 stainless steel body delivers reliable strength and corrosion resistance, ideal for machinery, automotive, and aerospace applications exposed to harsh operational environments. The green nylon tip prevents galling and damage to costly shafts or gears, making it perfect for adjustable couplings, pulleys, and collars where surface preservation is essential. With its UNC coarse thread and Class 3A fit, it ensures rapid installation and maintains clamp load under dynamic loads, reducing maintenance downtime. The temperature-resistant tip and Rockwell B80 hardness further enhance its suitability for industrial equipment requiring repeated adjustments and long service life.

Specification Summary & Compliance

This set screw adheres to ASME B18.3 standards, with a Class 3A thread fit for precise dimensional control and UNC 5/16"-18 coarse threading ensuring compatibility with standard components. It is manufactured from 18-8 Stainless Steel and features a nylon 6/6 tip with a diameter of 0.188" and length of 0.094". The product is fully RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting environmental and safety regulations for industrial use.