Heatfit - Unheaded - 1/4-20 UNC

The Unheaded Heatfit Insert with a 1/4-20 UNC thread is precision manufactured in brass to provide strong, reliable threaded connections in thermoplastics, plastic injection mouldings and 3D printed components. Designed for installation using either direct heat or ultrasonic methods, it offers a durable fastening solution for applications requiring imperial thread sizes.

Developed with an opposing herringbone knurl on the outside diameter, the insert delivers excellent resistance to torque and pull-out by maximising grip within the surrounding plastic. Its unheaded design provides a flush finish, while the pilot end aids accurate alignment and smooth insertion into drilled or moulded holes.

For the most consistent installation results, we recommend using a dedicated Heatfit installation machine, which precisely heats the insert to melt the surrounding plastic for secure retention while helping reduce the risk of damaging the component through uncontrolled heating.

Looking for a metric alternative? We also supply a full range of Metric Unheaded Heatfit Inserts for plastic applications.