S-91385A935 3/4"-10 x 1 1/4" ASME B18.3, ASTM F912 Set Screws

Key Features & Benefits at a Glance

• Vibration-resistant locking with integrated Nylon Pellet thread locker prevents loosening under dynamic loads, maintaining clamp force up to 250°F (121°C)
• Precise Class 3A thread fit ensures consistent engagement and reliable torque transmission in high-duty cycling applications
• Black-oxide surface treatment on alloy steel provides corrosion resistance while maintaining dimensional stability
• Rockwell C28 hardness rating delivers optimal balance of strength and ductility for repeated installation cycles
• Headless hex drive design enables flush mounting in confined spaces while accommodating standard 3/8" drive tools
• Cup tip configuration concentrates contact pressure for superior grip on shaft surfaces without damaging components
• Coarse UNC threading facilitates rapid installation and removal while resisting cross-threading incidents

Professional Applications & Engineering Value

This 3/4"-10 UNC set screw addresses critical vibration-induced failure points in industrial machinery, power transmission systems, and precision equipment. The black-oxide alloy steel construction combined with Class 3A thread tolerance ensures dimensional stability under thermal cycling and heavy loads. The Nylon Pellet locking mechanism actively compensates for micro-movements in rotating assemblies, eliminating the need for secondary locking components. Engineers specify this headless hex drive configuration for space-constrained applications where protruding fasteners interfere with moving parts or safety guards. The cup tip design provides superior bite on hardened shafts while minimizing surface deformation, making it ideal for permanent positioning of gears, collars, and pulleys in manufacturing and automotive applications.

Specification Summary & Compliance

Manufactured to ASME B18.3 dimensional specifications with Class 3A thread fit for precision engagement. The UNC coarse thread (3/4"-10) follows standardized spacing for compatibility with matching components. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations. Material certification includes Rockwell C28 hardness verification and black-oxide surface treatment per industry standards for corrosion protection.