Coil Springs
Coil springs return plates, strip parts and hold pressure in tools and machines. Standardised load classes make replacement fast — if you match the class correctly.
What are coil springs?
A coil (compression) spring resists being compressed and returns stored force as it extends. Industrial standard ranges are organised by outside diameter, free length and load class, usually colour-coded, so a worn spring can be swapped for an identical rating without recalculation.
Typical materials
Typically oil-tempered spring steel (e.g. SWOSC-V / piano wire grades); ends closed and ground for square seating.
Types of coil springs
Light load
Longer deflection at lower force — gentle return duties.
Medium / regular load
The general-purpose class covering most tool and machine duties.
Heavy / extra-heavy load
High force in the same envelope, at reduced allowable deflection.
Wire springs
Round-wire general springs in wide size ranges for machines and fixtures.
How to select coil springs
- Hole (OD) and rod (ID) sizes the spring must work within.
- Free length and required working deflection — stay inside the class's allowable %.
- Load class by colour code or required force at working height.
- Cycle life — reduce working deflection for long-life duties.
Not sure? Send what you have — a part number, drawing or photo — and our engineering team will confirm the selection.
Frequently asked questions
- What do coil spring colours mean?
- Colours identify the load class (light, medium, heavy, extra-heavy) within standard spring ranges — the same physical size is available in several force ratings, and the colour tells them apart.
- How much can a coil spring be compressed?
- Each load class has a maximum allowable deflection as a percentage of free length (heavier classes allow less). Staying below it — further below for high-cycle duty — is what determines spring life.
Related components
Die Springs
Die springs pack maximum force into a standard hole — rectangular wire and controlled stress make them the force standard in press tools.
Gas Springs
Gas springs deliver full force from the very start of the stroke — something no mechanical spring can do — which is why modern forming dies rely on them.
Ejector Pins
Ejector pins push the finished part off the core when a plastic mould or die opens. They cycle millions of times against heat and friction, so material, hardness and fit decide tool life.
Need coil springs?
Tell us the specification, quantity and application — or just send the drawing.