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Small Torsion Springs Assortment: Overview, Types & Applications
Small torsion springs are helical coil springs designed to resist torsion, twisting forces, and displacement at the torsion spring’s legs. Small torsion springs consist of tightly wound wire coils that elastically unwind as they absorb torsional loads, as the name suggests. The torsion spring stores energy by resisting forces that try to twist the spring coil into a tighter wind.
Small torsion springs feature compact dimensions and are manufactured to tight tolerances. By definition, they are designed to fit within small precision mechanisms with limited space for a spring. They are manufactured to the precise dimensional tolerances required to function reliably within such precision assemblies. Small torsion springs are found in precision machine components in many products, such as medical devices and electronics.
Depending on the spring type, the envelope that makes a torsion spring “small” is not a fixed definition, and there is some variability among spring suppliers. Specifically, your small torsion spring's size, material, and leg configuration depend on your application.
Explore Our Small Torsion Springs Range
Stock small torsion springs are available in the following spring sizes in the chart below. The Outer Diameters (OD) and the Wire Diameters (WD) are used to shop for available stock in small springs. In general, small torsion springs possess an OD smaller than 0.350 in.
Spring Type | Dim. | Small Springs |
Torsion Springs | OD | 0.151” to 0.350” |
WD | 0.016” to 0.035” |
Century Spring is proud to offer thousands of stock small and micro springs for sale in a wide selection of materials and sizes, available to ship today. You can browse by diameter, spring rate, material, and more. You can download the spring CAD before purchasing to verify that your spring fits in your application.
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Browse our full selection of small springs by spring type, filtering by wire size and outer diameter.
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Custom Small Torsion Springs
If you cannot find the small torsion springs you need in our expansive catalog, we offer custom ones with many configurable options, such as high-strength materials and custom leg orientations.
We bring decades of design and manufacturing expertise to your custom projects, with thousands of small torsion spring customization options ready to engineer into your spring to fit the most demanding applications and industries.
You can browse our selection of small torsion springs to understand the customization options available for custom development projects.
Custom Small Torsion Spring Manufacturing Capabilities
We proudly offer state-of-the-art manufacturing equipment to deliver high volumes of custom small springs. We have cutting-edge CNC compression self-monitoring and coiling machinery to manufacture custom sizes and styles to fit any design envelope.
We provide complete prototyping and tooling assistance services and are ready to partner with you in any stage of development, from initial design concept to final product procurement
Don’t waste another minute; contact our experts, and we will show you how we deliver small springs engineered for high performance in high-precision applications for use in the most demanding environments.
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Small Torsion Spring Information & Resources
Small Torsion Spring Types
Small torsion springs fabricated from medical-grade stainless steel allow medical devices, such as surgical hand tools and instrumentation, to function properly.
Small torsion springs are excellent for applications with limited design space envelopes requiring precision motion control and performance. Century Spring is your supplier for stock and custom small torsion springs, including double torsion springs, which feature two sets of coils wound in opposite directions.
We are your trusted partner in providing precision small springs for applications in the following industries.
How to Select a Small Torsion Spring
The same geometric properties of the helical coil define small torsion springs as compression and extension springs, such as the Wire Diameter, Outer Diameter (referred to as Body Diameter in torsion springs), and Spring Rate.
Furthermore, key geometric properties define small torsion springs, including, Leg Length, Number of Coils, Angle between Legs, and Wind Direction. The following sections will show how to measure and easily identify these parameters.
Additionally, the spring rate on a torsion spring, measured in torque per degree, is the torque required to compress the two legs toward the winding direction as measured by an angular displacement. This value describes the torque required at the spring legs to displace the torsion spring per degree.
After determining the working load your small spring must withstand, you can shop for small springs by these parameters, which allow you to determine the fit and function of your small spring in your application.
How to Measure a Small Torsion Spring
You can measure the critical small torsion spring features by following the steps below.
- Measuring the Body Diameter (or Outer Diameter)
Place the spring's body between the outside large caliper jaws until the jaws contact both ends of the spring. After verifying that the calipers are perpendicular to the spring body, read the measurement from the caliper display. The larger the body length, the more coils in the torsion spring. - Measuring the Wire Diameter
Locate one of the legs and place the outside large caliper jaws around this wire, ensuring the jaws touch both sides. Take the reading from the caliper at this location. - Measuring the Inside Diameter
Insert the small jaws of the caliper into the spring's helical coil to measure the torsion spring's Inside Diameter (ID). You can also calculate the spring's ID by subtracting two wire diameters from the spring’s Outer Diameter (OD). Measuring the Leg Length
The torsion spring legs are the straight wire portions of the spring that serve as the interface between the coils and the mechanism applying loads to the spring. Torsion spring leg lengths represent the leg length from the center of the torsion spring coil to the end of the leg.The best way to measure leg length is to use your calipers to measure the portion of the leg’s length starting from the end of the coil where the leg first straightens at the spring’s OD. Take this value and add half of the spring OD to it to arrive at the torsion spring’s leg length.
- Counting the Number of Coils
Place the torsion spring flat on its side and carefully count the total number of coils on the spring. The number of coils is simply a count of the helical coils on the body of the torsion spring. As the number of coils on a torsion spring increases, the spring rate decreases, meaning it takes less force to rotate the legs of the torsion spring through a given angle. Measuring the Angle between Legs (Leg Configuration)
This value is sometimes called the leg configuration and represents the angle between the legs when the spring is unloaded. Use a protractor to measure this angle, taking the angle towards the applied load direction. This angle determines how your spring fits into its intended application.You may also estimate the leg configuration by counting the total number of torsion spring coils, including the partial coil count. Each full 360-degree rotation represents a single coil count. For example, a spring with five coils is a zero-degree spring, a spring with 5.25 coils is a 90-degree spring, and one with 5.75 coils is a 170-degree spring.
- Determining the Torsion Spring Wind Direction
A torsion spring’s wind direction is denoted as either right-hand or left-hand wind. You can quickly determine your torsion spring’s wind direction by noting that a right-hand wind spring is coiled counter-clockwise while a left-hand wind spring is coiled clockwise.
Explore More Dimensional Measurement Guides
How to Measure Extension SpringsHow to Measure Compression SpringsHow to Measure Torsion Springs
FAQs About Small Torsion Springs
What material should I choose?
When evaluating small torsion spring materials, consider corrosion resistance and your application's temperature and loading requirements. Common stock materials for torsion springs include music wire or stainless steel. If you have additional design considerations, consider a custom spring material. For example, consider a high-strength steel alloy if your application experiences high loads or deformations. If corrosion resistance is paramount, you may want a stainless steel spring. A nickel-based alloy may be appropriate for use in applications that experience very high temperatures.
How can I extend the life of my small torsion springs?
In general, you can enhance the longevity of your small torsion springs by considering these design factors.
- Optimize your Design: To minimize stress, choose a small torsion spring with larger wire diameters or investigate whether you can reduce your application’s design loads.
- Consider Material and Environmental Protection: Choose suitable materials and treatments for specific environmental conditions.
- Cyclic Loading: If your application does have significant dynamically oscillating loads, you should check to ensure that the operating frequency is significantly lower than the spring's natural frequency to avoid resonance issues
What is a double torsion spring?
A double torsion spring consists of two sets of coils wound in opposite directions. One set wound clockwise and the other counterclockwise. These two coils are bridged in the middle (called the Hairpin), resisting the force by twisting in both directions simultaneously. The total torque exerted by the spring is calculated as the sum of the torques from both coils. Century Spring offers Custom-Made double torsion springs in various sizes and configurations.
Do I need a custom small torsion spring?
Standard small torsion springs are readily available in various sizes and specifications. However, if you determine that you need a design configuration that we do not carry in stock, call us today at 800-237-5225 or fill out our Custom Quotation Form today!
What tolerances can I expect on my small springs?
Spring tolerances depend heavily on the exact spring type and geometry. However, a few general rules apply to small torsion springs. The spring’s inside diameter (ID) tolerance depends on the Spring Index, which is the ratio of the wire size to the mean diameter. The higher the index, the larger the tolerance. Also, it is important to know that as we rotate the legs, the spring’s ID becomes smaller, so be careful to have enough room for the mandrel that works inside the ID of the spring.
Furthermore, a torsion spring’s leg length tolerance is generally 3% of the leg length, while the angle between the leg geometry tolerances ranges from +/-5 to 10 degrees. Finally, the spring rate tolerance ranges from +/-10% to +/-5%.
If you have additional questions or need tighter tolerances for your application, Contact our Design Team today for details.
Why Choose Century Spring
Our Commitment to Quality and Service
Century Spring is a quality-first, ISO 9001 and AS9100D certified, industry-leading spring supplier specializing in stock and custom springs. We are the most trusted name in spring manufacturing, offering products and expertise to serve every corner of small spring markets.
Our dedicated custom spring development and customer support teams help you navigate critical design criteria such as size, material, surface finish, and end type to find your application's optimal spring solution.
Our experienced product engineers, knowledgeable product quality team, and skilled manufacturing personnel always deliver the highest quality products to you faster than our domestic and international competitors. Our springs are always Made in the USA.
We offer rapid delivery on over 40,000+ in-stock designs available to ship today. We are committed to getting products to you as quickly as possible because we understand your design scheduling constraints.
Visit us today to discover how our commitment to quality and customer satisfaction vastly improves your product design process!
Innovation and Customization in Spring Manufacturing
We bring extensive design for manufacturability (DFM) expertise to your project. We also have dedicated, high-speed machines that can quickly scale high-quality spring production processes to large part volumes.
Our Manufacturing Services include prototyping and tooling assistance. We also have cutting-edge computational equipment simulation and testing techniques, such as CNC compression self-monitoring and coiling machinery. These capabilities enable us to deliver durable, reliable products across many custom sizes and styles.
Our team will work directly with you to create, refine, and optimize spring designs to fit specific tolerance, performance, and use case conditions. We are ready to partner to solve your most pressing design challenges.
Get In Touch
Contact Information
Contact Us directly today, and let our experts resolve all your technical and sales questions. We can also guide you through all our available secondary operations for each spring type and material.
If you need immediate assistance, you can always reach us at our dedicated phone line to speak directly with our team: 800-237-5225.
Request a Quote and Consultation
If you can’t find the small torsion spring that suits your needs in our catalog, you can always Request a Custom Quotation so we can partner with you to customize a spring design for your unique application.
Once we hear from you, our design team will follow up with a quote for a custom solution and be happy to answer any follow-up questions you may have.