Active Coils – The coils which are free to deflect when the spring is loaded.
Total Coils – All coils including the end coils.
Counting Coils – Look at the end of the spring, turn the spring the wire is at 12.00 o’clock, follow the wire round, each time the wire passes 12.00 o’clock it is a complete coil, when reaching the last full coil stop and estimate the remaining wire ie, ¼, ½ or ¾ etc. then add this to the number of full coils.
Spring Hand – The direction in which the spring is wound, Right or Left Hand.
Right of Left Hand – Look at the end of the spring, turn the spring so the start of the wire is at 12.00 o’clock, if the direction of the wire is to the right the spring is Right Hand (R/H), if the direction of the wire is to the left the spring is Left Hand (L/H).
Mean Coil Diameter – Outside spring diameter (O/D) less one wire diameter.
Deflection – Movement of ends of spring when a load is applied.
Rate – Change in load per unit deflection, normally given as pounds per inch (lbs/in) or Newton’s per millimetre (N/mm).
Load – Pressure at a given deflection.
Free Length – The overall length of a spring in the unloaded position.
Pitch – The centre of wire to the centre of wire of adjacent active coils (best practice is to specify active or total coils).
Ends Closed – Where the end of spring pitch is reduced so the end coils touch.
Closed and Ground Ends – As Ends Closed but ground square for more stable location.
Solid Height – Compressed length of a spring, when all the coils are touching with no spaces between.
Pull to Pull – The measurement between inside the wire hooks/loops at the end of the tension spring.
Hooks – Cut loops to form a hook for attaching spring to location.
Loops – Spring end coils lifted up from body of spring to form full loops for attaching spring to location.
Initial Tension – The pressure that keeps the coils of an extension spring together and must be overcome before the coils will open.
Free Angle – Angle between the legs of a Torsion Spring when there is no load applied.
Torque – A twisting action in torsion springs which produces rotation, equal to the load multiplied by the distance (or moment arm) from the load to the axis of the spring body.
Yes, springs can weaken over time due to factors like repeated use, high loads, and exposure to extreme conditions. Proper maintenance and selecting high-quality springs suited to the application can help minimise wear and extend their lifespan.
The four main types of springs are compression springs, which resist force when compressed; tension springs, which resist pulling forces when stretched; torsion springs, designed to store rotational energy; and die springs, built for heavy-duty applications under high loads. Each type serves specific functions across a range of industries, from automotive to industrial manufacturing.
Springs made from stainless steel or specialised alloys, such as phosphor bronze or Inconel, are highly resistant to rust and corrosion. For applications in harsh or wet environments, these materials ensure long-lasting durability and reliable performance.
The three most popular types of springs are compression springs, used to resist compressive forces in applications like machinery and vehicles; tension springs, which stretch to absorb and store energy; and torsion springs, designed for rotational movement in devices like hinges and clocks. These versatile springs are widely utilised across industries due to their adaptability and reliability.
The strongest springs are typically die springs, designed to handle extremely high loads and frequent cycles, making them ideal for heavy-duty industrial applications. Constructed from robust materials like high-tensile steel or rectangular wire, these springs provide exceptional durability and strength under intense pressure.
Most coil springs are made of high-tensile steel, a material known for its strength, flexibility, and resistance to wear. This steel is often treated with processes like heat treatment or coating to enhance durability and performance in various applications.