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W.B. Jones Spring Co., Inc.
140 South St.
Wilder, KY 41071

Phone:
Fax: 1-859-581-7700
sales@springsfast.com

SMI Founding Member

WM Jones corporate video

Springs Fast Since 1913

Glossary

Term Definition
Active coils Those coils which are free to deflect under load.
Body length The length of an extension spring in the unloaded position for the coiled part only.
Buckling Bowing or lateral deflection of compression springs when compressed.
Close wound Coiled with adjacent coils touching.
Closed length See "solid height".
Coils per inch See "pitch" as this is difficult to measure.
Deflection Movement of spring ends or arms under the application or removal of an external load.
Direction of wind Important in the use of torsion springs. The load should cause the springs to rotate in the same direction in which it is coiled. This can be either right hand or left hand.
coil springs Right Hand coil springs Left Hand
Elastic limit Maximum stress to which a material may be subjected without permanent set.
End style - crossover end of extension springEnd of extension spring which is formed by coming across the center of the spring then forming a circle for the end.
End style - machine end of extension springEnd of extension spring which is formed by coming directly off the body then forming a circle across the center for the end.
End style - side extension springEnd of extension spring which is formed by a circle at the outside diameter for the end.
End type - double loop extension springEnd of extension springs with two coils in which there is no gap between the coils and the end of the wire.
End type - hook extension springEnd of extension springs with one coil in which there is a gap between the coils and the end of the wire.
End type - single loop extension springEnd of extension springs with one coil in which there is no gap between the coils and the end of the wire.
Ends - closed and ground closed and ground springSame as "closed not ground ends", except that the end is ground to provide a flat plane.
Ends - closed not ground compression springsEnds of compression springs where pitch of the end coils is reduced so that the end coils touch.
Ends - open and ground open and ground ends detail photoSame as "open not ground ends" followed by an end grinding operation.
Ends - open not ground compression springEnd of a compression spring with a pitch for each coil (last coils not touching).
Free length The length of a compression spring in the unloaded position.
Hydrogen embrittlement When hydrogen is absorbed in electroplating carbon steel, tending to make the spring susceptible to failure.
Initial tension The force that tends to keep the coils of an extension spring closed and which must be overcome before the coils start to open.
Inside hook length The length of an extension spring in the unloaded position from the inside of one end to the inside of the other.
Load The force applied to a spring that causes a deflection.
Mean coil diameter Outside spring diameter (OD) minus one wire diameter.
Overall length The length of an extension spring in the unloaded position from over top of each end.
Passivating Acid treatment of stainless steel to remove contaminants and improve corrosion resistance.
Permanent set A material that is deflect so far that its elastic properties have been exceeded and it does not return to its original condition upon release of load.
Pitch The distance from center to center of the wire in adjacent active coils.
Preset see "remove set"
Rate Change in load per unit of deflection, generally given in pounds per inch.
Relationship of ends The relative position of the plane of the hooks or loops of an extension spring to each other measured in degrees
extension spring detail photo - inline hooks ends
Inline
extension spring detail photo - opposite hooks ends
Opposite
extension spring detail photo - 90 degrees hooks ends
90 Degrees
Relationship of legs The relative relationship between the legs of torsion springs at the tangent point in the free position measured in degrees.
coil springs
90° Free Position
coil springs
180° Free Position
coil springs
270° Free Position
coil springs
360° Free Position
Remove set The process of closing to solid height a compression spring which has been coiled longer than the desired finished length, so as to increase the apparent elastic limit.
Set Permanent distortion which occurs when a spring is stresses beyond the elastic limit of the material.
Shot peening A cold working process in which the material surface is peened to induce compressive stresses and thereby improve fatigue life.
Solid height Length of a compression spring when under sufficient load to bring all coils into contact with adjacent coils.
Space between coils The actual space in between the coils of the springs as measured from the top of one coil to the bottom of the next coil.
Spring Index Ratio of Mean coil diameter to wire diameter.
Squared and ground ends See "Ends - closed and ground".
Squared not ground ends See "Ends - closed not ground".
Stress relieve To subject springs to low temperature heat treatment so as to relieve residual stresses.
Torque A twisting action in torsion springs which tends to produce rotation, equal to the load multiplied by the distance from the load to the axis of the spring. Usually expressed as inch pounds.
Total number of coils Number of active coils plus the coils forming the ends.
Wire - brass Used for applications requiring water resistance also know as ASTM B134. Modulus of elasticity is 16,000,000 psi, the modulus in torsion is 6,000,000 psi, and maximum operating temperature is 200 degree F.
Wire - chrome silicon Same as chrome vanadium except can handle higher stresses also know as ASTM A 401. Modulus of elasticity is 30,000,000 psi, the modulus in torsion is 11,500,000 psi, and maximum operating temperature is 250 degree F.
Wire - chrome vanadium An alloy material used for high stresses in larger wire sizes also known as ASTM A 231. Modulus of elasticity is 30,000,000 psi, the modulus in torsion is 11,500,000 psi, and maximum operating temperature is 250 degree F.
Wire - hard drawn MB A carbon steel used for low stresses and lower cost also known as ASTM A 227. Modulus of elasticity is 30,000,000 psi, the modulus in torsion is 11,500,000 psi, and maximum operating temperature is 250 degree F.
Wire - music A high carbon steel used for high stress applications also known as ASTM A 228. Modulus of elasticity is 30,000,000 psi, the modulus in torsion is 11,500,000 psi, and maximum operating temperature is 250 degree F.
Wire - oil tempered A carbon steel used for wire forms and torsion springs also known as ASTM A 229. Modulus of elasticity is 30,000,000 psi, the modulus in torsion is 11,500,000 psi, and maximum operating temperature is 250 degree F.
Wire - phosphor bronze Used for electrical applications also know as ASTM B 159. Modulus of elasticity is 15,000,000 psi, the modulus in torsion is 6,250,000 psi, and maximum operating temperature is 200 degree F.
Wire - Stainless steel (302) Used for high temperature and corrosion resistance but is magnetic and also known as ASTM A 313 or AISI 302. Modulus of elasticity is 28,000,000 psi, the modulus in torsion is 10,000,000 psi, and maximum operating temperature is 550 degree F.
Wire - stainless steel (316) Same as 302 stainless except better resistance to heat and corrosion also known as ASTM A 313 or AISI 316. Modulus of elasticity is 28,000,000 psi, the modulus in torsion is 10,000,000 psi, and maximum operating temperature is 550 degree F.