What Are Spring Pins?


Gear illustration

Mechanical fasteners aren’t limited to bolts and screws. There are other types of mechanical fasteners with which you can join and secure multiple parts together. Spring pins, for instance, are commonly used with machinery parts. Also known as tension pins, they consist of a spring-like rod or pin.

Overview of Spring Pins

Spring pins are mechanical fasteners that join and secure multiple parts together via compression. They are essentially compression springs. Spring pins are cylindrical compression springs that are designed for use in a hole. When you place a spring pin in a hole with a smaller diameter than itself, the spring pin will compress against the inner walls of the hole. This compressive force will hold the respective parts together.

Slotted vs Coiled Spring Pins

Most spring pins fall under one of two categories: slotted or coiled. Slotted spring pins are characterized by the presence of a slot. They still feature a cylindrical shape. Rather than being completely solid, though, slotted spring pins have a vertical notch or slot. This open notch or slot makes them flexible. Slotted spring pins will compress when placed into a hole with a smaller diameter, at which point the notch or slot will close.

Coiled spring pins are characterized by a coiled design. They are typically made of a single piece of metal that’s been rolled up into a coil. Coiled spring pins are available in standard, heavy and light duty ISO specifications. And you can find them in different sizes. Regardless, they all feature a coiled design. Slotted spring pins don’t feature this same coiled design. Instead, they are cylindrical-shaped mechanical fasteners with a vertical notch or slot running down the side.

How to Use a Spring Pin

You can use a spring pin by placing it through a hole that’s formed with two or more parts. The hole, of course, must have a smaller diameter than the spring pin.

Spring pins are designed to compress against the inner walls of the hole in which they are placed. They may not look like springs, but spring pins still perform the same energy-storing action as conventional springs. They will store mechanical energy while simultaneously using it to generate a compressive force. Spring pins leverage this compressive force to hold multiple parts together.

In Conclusion

When most people think of mechanical fasteners, they envision bolts and screws. While bolts and screws are, in fact, mechanical fasteners, there are others from which you can choose, including spring pins. Spring pins are cylindrical mechanical fasteners that rely on the properties of a compression spring to hold multiple parts together.

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