Spring plungers: A key component for many machines and devices

Spring plungers are an essential component of many machines and devices. They are most commonly used for clamping parts, but also for indexing or positioning. Choosing the right spring plunger can significantly simplify your work with components or workpieces. Despite their small size, spring plungers can replace complex fixtures that are expensive and take up a lot of space.

Example of use:

The name “spring” plunger comes from its functionality. Inside the housing is a spring that pushes a ball or a plunger pin outward. When external force greater than the spring force is applied, the ball or pin retracts back into the housing. This feature allows the product to be used in a wide range of applications. Spring plungers are among our best-selling products, therefore we continuously expand the range with new dimensions and materials. To ensure the widest usability, we offer spring plungers in various materials. In many designs, the entire housing with the spring-loaded ball is not made from one material — the housing, ball, or pin can be made from different materials, creating a wide selection of variants for different applications.

The official name is “spring plungers”, but you may also know them as spring screws, spring-loaded screws, ejector pins, or screws with a ball/pin.

Types of spring plungers by material

Plastic housings with spring-loaded ball

Advantages: lightweight, low cost, corrosion resistance. Suitable for outdoor or humid environments.

Steel housings with spring-loaded ball

Advantages: stability, resistance to higher forces and temperatures. Ideal for demanding environments.

Stainless steel spring plungers

Advantages: corrosion resistance, suitability for higher temperatures and outdoor use. Lighter than steel versions.

Smooth-design spring plungers

These plungers are designed for press-fit installation or insertion into a hole instead of threading. They are available in stainless steel or plastic (POM).

Additional features and installation

Available sizes

Spring plungers are manufactured according to standards and available in sizes M5, M6, M8, M10, and M12. All available dimensions can be found on our website, where you can use filters to select the correct type.

Installation

Depending on the application, spring plungers can be mounted in various ways. Those with smooth housings can be press-fitted, manually pushed in, or inserted during the plastic injection molding process. Spring plungers with threaded housings are installed using a standard screwdriver or hex key into a threaded hole. For blind holes, spring plungers can be screwed in using a special tool. To prevent loosening, they can be secured with nuts. For greater reliability, however, it is recommended to use spring plungers with thread locking (Long-Lok), which eliminates the need for additional nuts against loosening or vibrations.

Spring force of the plunger elements

Spring plungers are produced with different spring forces. Depending on the forces acting on the workpiece during machining, it is reasonable to choose the appropriate spring strength. Each product includes the relevant force specifications.

Ball or plunger pin?

In the KIPP product range, you will find housings with a spring-loaded ball and spring plungers with a plunger pin. Depending on the design, they are suitable for different applications. Balls are very suitable for simple clamping and locking operations. Plunger pins, on the other hand, are more often used as ejector pins for pushing objects back out.

Selecting the correct spring plunger

When choosing the right spring plunger, it is important to know:

Dimensions (thread size, length, ball/pin travel)
Material (steel, stainless steel, plastic)
Drive type (slot, hex)
Spring force (initial and final force)

Document

1) Material of housing/ball

a) Steel

b) Stainless steel

c) Plastic (POM)

2) Drive type

a) Slot for screwdriver

b) Hex socket

3) Spring preload (Spring force in Newtons)

a) Initial spring force F1 (Force at which the ball/pin begins to retract)

b) Final spring force F2 (Force at which the ball/pin is fully compressed)

If you need assistance choosing the right spring plunger, do not hesitate to contact us via email or phone.

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