What is a Spring Plunger?

spring-plunger-fwA spring plunger, also known as a spring-loaded device (SLD), is a small and narrow device that’s used for indexing and positioning of various components. Once installed, it  applies adequate pressure so the ball or nose remains positioned. To learn more about spring plungers and how they are used, keep reading.

The spring plunger lives up to its namesake by using “spring force” to apply pressure. This allows the ball (found at the end) to remain positioned at all times, regardless of how much pressure is exerted upon it. Spring plungers can be installed in several different ways, some of which include hex sockets, standard, heavy force and more.

The 3 Pieces of a Spring Plungers

Spring plungers are available in dozens of different sizes and types, each of which has its own purpose. Most, however, feature just three basic components: the plunger, internal compression spring, and threaded body. The threaded body is the housing component that encapsulates the spring, while the plunger rests on the very tip/end, allowing for accurate force to be exerted. It’s a relatively simple design that proves particularly useful in manufacturing applications.

Benefits of Using Spring Plungers

There are several benefits associated with the use of spring plungers, one of which is its simplicity. When compared to standard, non-loaded springs, spring plungers are typically easier to install. Furthermore, they allow for accurate and repeatable forces to be exerted — something that’s difficult to achieve using standard springs.

Given their utility in the manufacturing industry, you may assume that spring plungers are expensive. However, they are actually inexpensive, making them an excellent choice for budget-conscious business owners and consumers.

Things to Consider When Choosing Spring Plungers:

  • What material is it made of? Stainless steel is an excellent choice, as it offers natural protection from rust and corrosion.
  • Are they coated? Even if the actual spring plunger is made of stainless steel, it may feature some other exterior coating for added protection.
  • What’s the installation method? Again, you’ll find that different spring plungers have different installation methods such as hex socket, slotted drive, and top slot for blind holes.
  • What size is it? Common sizes for spring plungers include .35 inch to 1.75 inch.
  • How much pressure does it need to exert? This is pretty self-explanatory, as you need to determine how much pressure the spring plunger needs to exert.


See Monroe’s Spring Plungers.