

Extension springs are helical wound coils, wrapped tightly together to create tension. Extension springs are designed to resist a pulling force, returning to a tightly wound coil when the force is removed.
Custom extension springs from Springfield Spring & Stamping are manufactured on state-of-the-art CNC wire forming equipment (for example, the CNC Itaya Wire Former; the CNC Orimec MLS-10V). This allows us to offer a wide variety of custom extension spring options with various end types; our custom extension springs are available with machine, crossover, side, or extended end options.
Materials
The highest grades of spring wire are used in manufacturing Springfield Spring & Stamping products. “Spring steel” is a term that includes music wire, hard-drawn wire and oil-tempered wire. Alloy steels for stock extension springs are offered only in 300 series stainless steel. For custom extension springs, we offer several steel and metal options depending on your specifications.
Tolerances
Tolerances for extension spring rates depend upon the body-diameter to wire-diameter but are usually +/- 10% and +/- 5% on the diameter. The initial tension is much more difficult to control and is offered as a reference value only.
End Configuration
The hooks or loops may have an across center transition of the last coil before forming the hook or loop. The angle between hook/loop planes (end position) is random. If you need a specific end configuration on your custom extension spring, please contact our custom spring department directly.
Note: These are sample values, and will be replaced.
Wire Diameter Min | Wire Diameter Max | Spring End Types |
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.008 in .201 mm |
.135 in 3.4 mm |
Machine Crossover Side Extended |
Direction of Helix | Spring Materials | Finishes |
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Left Right |
Music Wire Pre Tin-Coated Music Wire Pre-Galvanized-Coated Wire Hard Drawn MB Oil Tempered Stainless Steel Phosphor Bronze Beryllium Copper Brass |
Black Oxide Duirem Color Code Manganese Phosphate Nickel Plating Painting Passivation Phosphate w/ Oil Powder Coated Tin Varnish Zinc (Clear and Yellow) |
Equipment | Secondary Services | Industry Focus |
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CNC Machinery (Itaya Wire Former and Orimec MLS-10V) SPX-Z11 22000 sq-ft Facility |
Pre-Qualifying Engineering Cost Reduction Programs Statistical Process Control (SPC) International Shipping Automative FMEA and PAPP |
Computer Hardware Pneumatic Tools Medical Devices Industrial Controls Wiring Devices Electronics Imaging Equipment Surgical Instruments Aerospace Timing Devices Head Sets Printed Circuit Boards Telecommunications Windows/Screens Hand Tools Automotive Musical Instruments Houseware Oil Filters Pumps Photographic Lawn and Garden Tools Toys Forklifts Valves Firearms Military Hardware Fasteners Instrumentation GI Endoscopy Lighting Elevators Battery Chargers Locks Switches/Solenoids Insert Molding Air Filter Hardware Electric Coils Contract Manufacturing Laser Toner Recharge Ribbon Cassette |
Production Volume Min | Production Volume Max | Industry Standards |
---|---|---|
1 unit Speciality Production Shop Prototype (Rapid Prototyping for Design Qualification) |
Millions of units Low Volume Small Run High Volume Long Run |
ANAB Accredited ANSI/ASQ National Accreditation Board ASTM American Society for Testing and Materials DFARS Compliant ISO International Organization for Standardization (ISO 9001:2008) ITAR Registered International Traffic in Arms Regulations Mil-Spec Military Specifications NMSDC-Certified National Minority Supplier Development Council RoHS Restriction of Hazardous Substances (Compliant) REACH Registration Evaluation Authorization and Restrictions of Chemicals SAE Society of Automotive Engineers SBA-Certified SDB/MBE Small Business Administration |
File Formats |
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We utilize CADKEY Creator and can translate most of the common CAD files for use AutoCAD (DWG and DXF) BMP Bit Mapped Graphics GIF Graphics Interchange Format IGES JPG or JEPG Joint Photographic Experts Group TIFF Tagged Image File Format |