Exchange Knowledge & Develop Ideas

Contact Us

Knowledge Hub

Compression Spring End Types


Compression Springs: The forms they come in and their applications

There are a few options when it comes to end type selection for a compression spring. The two most common are ‘closed and ground’, and ‘closed not ground’. Generally speaking, end grinding is an expensive process, and is therefore to be avoided wherever possible. The ‘closed not ground’ option can often be selected where spring end squareness is not critical. As the spring index (mean diameter/wire diameter) ratio increases, the need to grind reduces, as large index springs tend to stand fairly square without grinding. Grinding can be difficult on large index springs anyway, as the spring yields too easily under the pressure applied by the grinding wheel.


For small wire diameters, grinding is also impractical, so unground ends are normally specified for wire under 0.5mm, although it is possible to grind smaller wires, with care, if absolutely necessary.


In many applications however, there is no question that the springs will need to be ground. For instance, valve springs will need to be very square to ensure that the valve seat seals properly. End grinding can also help with spring stability; an unground spring is more susceptible to buckling under load than one that is ground.


Other end type possibilities exist, such as ‘open’, ‘open and ground’, and ‘half-closed’ (ground or unground). These are used comparatively rarely however, as spring stability is poor.


Multiple inactive coils are sometimes used at the ends of compression springs. Generally this is done to help prevent tangling. When compression springs are packed in bulk, springs will often tangle (dependent upon the design). Using perhaps three or four dead coils at each end means that these close-coiled sections are longer than the gap between the active coils in neighbouring springs, and are therefore less likely to lock together.

Latest News From Advanex

Our Global Network


Join our global partnerships Contact