3591-4CN250 - Helicoil ® Threaded Insert by Stanley ® Engineered Fastening

Part 3591-4CN250 is a premium Heli-Coil tanged screw-locking fine thread insert engineered for superior thread reinforcement and repair. Manufactured from durable stainless steel, this 1/4"-28 insert features a UNF thread series and a screw-locking design that prevents fastener back-out under heavy vibration. It has a body length of 0.25 in | 6.3500 mm with a 1D length-to-diameter ratio and tanged configuration for easy installation. Supplied in bulk, it provides reliable, high-strength performance for demanding industrial applications.

Stainless Steel Material Crafted from robust stainless steel to provide long-lasting durability and reliable resistance against environmental corrosion.

Screw-Locking Mechanism Incorporates a specialized internal locking coil that applies resilient pressure against the mating bolt threads to prevent loosening from vibration.

Tanged Style Designed with a traditional tanged configuration to facilitate efficient installation using standard insertion tools.

Fine Thread Series Engineered with a 1/4"-28 UNF fine thread specification to ensure tight, secure, and precise engagement.

Compact Length Features a body length of 0.25 in | 6.3500 mm corresponding to a 1D ratio, making it ideal for standard depth threaded holes.