Continuous Length

Spring Strips for Prototyping, Development and Custom Spring Lengths

Spring strips are long, cylindrically coiled spring bodies that can be cut to the length required for a specific application. They are particularly suitable for prototyping, product development, repairs and testing where a suitable standard spring has not yet been defined or where different spring lengths need to be evaluated.

Febrotec offers spring strips as compression spring and extension spring versions with an initial length of 1,000 mm. After cutting, however, they do not automatically become ready-to-install precision springs. The spring force, travel, end design and permissible load of the resulting component must be assessed separately.

Meaning of the Specifications in the Product Table

Compression Spring Strips

Compression spring strips have spacing between the coils and are compressed axially under load. Cutting them to length allows spring bodies with different installation lengths to be produced.

The shorter the section, with all other dimensions remaining unchanged, the fewer active coils it has and the higher its spring rate generally becomes. A short section is therefore not only smaller but also stiffer than a longer section from the same spring strip.

Cutting produces open ends that are neither closed nor ground. The spring may therefore stand unevenly on a flat surface or apply the force irregularly. For precise, dynamically loaded or safety-relevant applications, the end design must be specified and produced correctly.

Extension Spring Strips

The coils of extension spring strips lie closely together when unloaded. They are extended axially and require suitable end attachments for applying the force.

The strips are supplied without finished loops or hooks. The end design must therefore be included in the construction of the final extension spring. Bending hardened spring wire afterwards may cause cracks, permanent deformation or reduced service life. Heating, welding or uncontrolled forming should be avoided.

In addition to the spring rate, initial tension and the design of the end attachments may affect the actual force. The cut component should therefore be tested under real operating conditions.

How to Select the Correct Spring Strip

Proceed in the following order:

1. Select the spring type: compression spring strip for compressive loads or extension spring strip for tensile loads.

2. Compare the outside and inside diameters with the available space, guide and surrounding components.

3. Select the wire diameter and pitch to suit the required force and travel.

4. Determine the required section length and resulting number of coils.

5. Define the end design, attachment method and cutting process.

6. Select the material according to the operating environment.

7. Produce a sample and test the spring force, travel and secure fit.

Spring steel 1.1200 is suitable for many general applications in dry environments. Stainless spring steel 1.4310 offers improved corrosion resistance. Suitability for seawater, chlorides, acids or aggressive cleaning agents must be assessed separately.

Cutting and Processing

The spring strip should be cut using a suitable method that produces a clean cut with minimal burr formation. It must be held securely without crushing adjacent coils.

Sharp edges must be removed after cutting. Safety glasses and suitable gloves should be worn because the spring wire and cut ends may spring back unexpectedly.

Spring strips are primarily intended for testing, prototypes and individually adapted solutions. For series production, defined service life or accurately specified forces, a fully calculated and manufactured spring is recommended.

Frequently Asked Questions About Spring Strips

Can I simply cut the spring strip to the required length?

In principle, yes. However, the spring rate, end design, travel and load capacity of the resulting section must then be checked.

Does the spring rate remain unchanged after shortening?

No. The reduced number of active coils generally makes a shorter section stiffer.

Do extension spring strips already have loops?

No. A suitable end attachment must be added as part of the design.

What are spring strips particularly suitable for?

They are suitable for prototyping, repairs, development, testing and applications requiring individually selected spring lengths.

Ready-to-install standard springs can be found in our compression spring and extension spring ranges.