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Stock Springs Vs Custom Springs

Here at the Fox Valley Spring Company, we are a custom spring manufacturer. What that means is that we can design and manufacture springs and wire forms to our customer's exact dimensions and requirements. Unlike stock springs, they are not off-the-shelf items, but rather made to order. Despite being a custom manufacturer this does not mean we can't manufacture a stock spring should that be all you need.

Stock springs will come in a variety of sizes and are typically held to more liberal tolerances. The intent is that the spring can be used for a variety of general applications or non-critical functions. They are usually already made and sitting on the shelf.

Choosing a custom spring allows you to tighten the tolerances on any critical dimensions, request special spring material, select an appropriate finish or add other components for a completed assembly.

If you have a custom application, then a custom spring is your best chance of getting the part you need with the performance you require. Our 10-piece minimum will also allow you to test your design before putting in a large order.

Your application may require a precise free length, outside diameter or even spring force. Tighter tolerances may be required to deliver improved and consistent performance. When we assist you during the design stage, we take it a step further and monitor stress levels to ensure that we also deliver durability. This absolutely proves critical in applications where safety or performance are desired in your product.

Some custom springs can be referred to as precision springs. They are designed and manufactured to precise or exact dimensions. Variables such as cycle life and the exposed environment may be taken into consideration to deliver durability and product performance. Your options with a custom spring become limitless! We warehouse a variety of materials to deliver your custom products with a highly competitive lead time. our in-house experts are available to assist.

Need a custom part? Request a quote today.

Common Spring Terms

Active Coils (n) - The coils which are tree to deflect under a force.

Alloy - A metal composed of two or more metal elements bound together.

Arbor - A round rod on a spring coiler over which wire is coiled to form a spring.

ASTM - The American Society for Testing Materials.

Baking - Heating electroplated springs to remove hydrogen.

Brass - A copper-based alloy or copper and zinc.

Bronze - A copper-base alloy of copper and tin.

Buckling - Lateral deflection movement of a compressed spring and is related to the slenderness ratio.

Deflection (F) - Displacement of the ends or arms of a spring on the application of an external force.

Elastic Limit - Maximum stress which a spring can be stressed without taking a permanent set.

Endurance Limit - Maximum stress which can be repeatedly applied without incurring spring failure.

Fatique Failure - When a spring is deflected continually the metal becomes fatigued and failure may occur at a stress level far below the elastic limit.

Fatique Life - Number of deflection cycles until a failure occurs at a predetermined stress.

Fatique Strength - Stress at which failure occurs after a specific number of deflections.

Force (P) - Active power applied to a spring to cause deflection, often erroneously called load.

Free Angle - Angle between the arms of a torsion spring when the spring is not loaded.

Free Length - The overall length of a spring in the unloaded position.

Frequency (Natural) - The number of cycles per minute at which a spring will vibrate treely once it has been excited.

Gauge - A standard for measuring material thickness

Gradient (Rate) (R) - Change in force per incremental unit of deflection.

Heat Setting - Deflecting a spring in a fixture at elevated temperatures to reduce loss of load at operating temperature.

Helical - Sprinas of spiral or cylindrical shape such as compression, extension, or torsion springs.

Hysteresis - The difference in forces at various deflections when loading and unloading a spring.

Initial Tension (Pi) - A force wound directly into an extension spring during coiling to hold the coils together.

Load (Force) (P) - Active power applied to a spring to cause a deflection (F).

Modules in Shear or Torsion (G) - Coefficient of stiffness for extension and compression springs.

Modules in Tension or Bending - Coefficient of stiffness for torsion and flat springs.

Passivating - An acid dipping treatment applied to stainless steel to remove contaminants and improve corrosion resistance

Permanent Set - The difference in length of a highly stressed spring upon release of a force.

Pitch (p) - The distance from the center of the wire in two adjacent coils.

Preset - The process of closing to solid height a compression spring which has been coiled longer than the desired finish length, to increase the apparent elastic limit.

Proportional Unit - Maximum load at which strain or deformation is directly proportional to stress, at zero percent offset.

Rate (R) (Gradient) - Change in force per incremental unit of deflection

Residual Stress - Stresses incorporated within a spring by coiling, compressing to remove set, shotpeening, cold working or induced by

Resilience - Elastic ability of a material to rebound to its original shape after deflection.

Set - Permanent distortion which occurs when a spring is stressed beyond the material's elastic limit.

Slenderness Ratio - Ratio of spring free length (L) to the mean coil diameter (D). If the ratio is over 4.0. compression springs may buckle depending on the amount of deflection.

Solid Height (HI) - Length of compression spring when force causes coil contact with all adjacent coils.

Spring Index - Ratio of mean coil diameter (D) to wire diameter (d). Best ratio is between 7-13.

Strain - The deformation produced by a stress as compared to the original shape.

Stress - The force divided by the area over which it acts.

Stress Relieve - Low-temperature heat treatment to relieve residual stresses induced during coiling.

Tensile Strength - Maximum force which a material is capable of sustaining. It equals the force reached divided by the original cross-sectional area

Torque (Movement) - A twisting force in torsion springs that tends to produce rotation, equal to the force multiplied by the distance from the force to the axis of the spring body.

Total Coils (N) - Number of active coils (n). For compression springs, add to (n) the number or dead coils forming the end

Yield Point - Stress point which will cause an elongation to the original length or the spring.