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Coil Springs Made to Order
Definition
Custom coil springs manufactured to meet a specific design made by the user to meet their mechanism’s requirements.
Made to the dimensions the customer orders.
Springs Made to Order
Coil springs made to order are also known as custom springs or specialty springs. Acxess spring manufactures many types of coil springs made to order. The most basic coil springs are compression springs, extension springs, torsional springs, and conical springs This is why we have stock items of this kind. There are more complex coil spring types that will definitely need to be made to order. These custom springs include barrel springs, garter springs, magazine springs, non-linear dual pitch springs, and wire rings. Some of these are shown in the images to the right.
Basic Spring Types
We meet the needs of multiple industries by working with a wide range of both material types and wire diameter sizes; which are the what defines a spring company’s manufacturing capabilities. Not only are we able to manufacture springs for the medical or construction industries but we’re also able to help you design them based on the device’s requirements. For example, if you need a heavy duty spring with a three eighths wire that’ll be placed into a corrosive environment, we can definitely use 0.375” Stainless Steel 302 and begin your design from there. The same goes if you need a medical spring made to order with 0.007” wire and Stainless Steel 316 (which is a much cleaner material type).
Other spring devices may require custom alterations like bends or legs which aren’t “included” in the “normal/usual” manufacturing of these springs. In the case of a compression spring, you may request that it has dual pitch, different diameters, or a certain bend on the ends for installation. These are custom compression springs which you will not be able to find in stock ANYWHERE. In this case you may email us a specific drawing showing all of these requirements with precise measurements or mail us a sample so that we may do an exact replica. Remember, we will make the springs to order so if your measurements aren’t accurate on the drawing, they might also not be accurate once they come off the machine.
Type of Springs
In the case of an extension or torsion spring, the custom accommodations some customers prefer involve certain specialty bends or loops on the legs (for a torsion springs) or hooks (for an extension springs). Some torsion springs might even have some pitch in between the coils; turning this spring into a torsional compression springs which will produce both a rotational “torque” and a linear (up and down) force.
Other springs don’t necessarily need to have custom alterations to the design to be made custom. These springs are the more complex designs which were mentioned earlier. Garter springs, for example, not only have different sizes and dimensions, they also have different types of connectors. Magazine springs aren’t circular coil springs but oval/rectangular coil springs. Dual pitch springs have different amounts of pitch on different areas.
Custom / Specialty Spring Types
Attention! Input results shown will be +/- 10% from middle value. Hint: The closer your min and max inputs are, the more accurate your results will be!
Attention! Input results shown will be +/- 10% from middle value. Hint: The closer your min and max inputs are, the more accurate your results will be!
Attention! Input results shown will be +/- 10% from middle value. Hint: The closer your min and max inputs are, the more accurate your results will be!
Table of Contents
- What Are Coil Springs Made to Order?
- Key Characteristics in Spring Design
- Using Online Tools for Faster, More Accurate Spring Design
- Understanding Tolerances and Manufacturing Variances
- Ensuring Quality and Performance
- Final Steps: Ordering Your Custom Spring
- 5 Essential Tips for Designing Perfect Custom Coil Springs
What Are Coil Springs Made to Order?
Coil springs made to order—also referred to as custom springs—are fabricated to match precise specifications defined by the user or engineer. These specifications may include wire diameter, outer diameter, free length, spring rate, load requirements at certain deflections, and even special end treatments or hooks. Because each of these variables can drastically change how a spring performs, the ability to customize them ensures that you won’t have to compromise on your mechanism’s design. Custom coil springs often improve overall device performance by eliminating fitment issues or mechanical inefficiencies that can arise from using a spring not tailored to the application. Furthermore, because custom springs are engineered for your specific environment—whether it’s high-temperature, corrosive, or in need of strict cleanliness standards (such as in medical devices)—the correct material can be selected right from the start to enhance durability and functionality.
Why Choose Custom Springs?
- Exact Fit and Function: When you specify a custom spring, you eliminate the guesswork that comes with off-the-shelf solutions. This level of precision helps ensure your spring will not bind, buckle, or fail prematurely due to mismatched dimensions.
- Special Materials: Not all environments are the same. Some require springs to endure corrosive chemicals, high humidity, or extreme temperatures. In such cases, selecting the right material—like Stainless Steel 316 (ASTM A316)—can dramatically extend the life and reliability of your spring.
- Complex Designs: Certain spring types—like barrel springs, magazine springs, garter springs, and dual-pitch springs—are rarely available as standard items due to their specialized geometry and function. A custom solution ensures these unique configurations can be achieved accurately, aligning with your device’s design parameters and performance goals.
- Custom Alterations: Small details such as bending legs at a certain angle, adding hooks, or adjusting coil pitch can have a significant effect on how a spring works in practice. When ordering a custom spring, you can specify these nuances to achieve a near-perfect fit, rather than settling for a generic model that only partially meets your needs.
Key Characteristics in Spring Design
Materials
Material selection is arguably one of the most critical choices when designing a custom spring. Different metals and alloys have distinct mechanical properties, including tensile strength, modulus of rigidity, fatigue resistance, and corrosion resistance. Stainless Steel 302 (ASTM A313) is a go-to material for general-purpose springs, offering a good balance of elasticity, corrosion resistance, and cost-effectiveness. Stainless Steel 316 (ASTM A316), on the other hand, excels in environments where rust or chemical exposure is a higher risk, making it particularly suitable for medical or marine applications. Music wire (ASTM A228) is known for its high tensile strength and is commonly used in tightly wound springs that need to withstand numerous compression-extension cycles without deforming. Phosphor bronze (ASTM B159) is chosen when electrical conductivity or non-magnetic properties are required. By collaborating closely with your spring manufacturer and using reliable material data tables, you can pinpoint which alloy best matches your performance requirements, environmental conditions, and budget constraints.
Dimensions
Dimensions form the backbone of any spring design. The Wire Diameter (d) directly impacts the spring’s load-carrying capacity and stiffness; thicker wires generally support heavier loads but require more force to compress or extend. Determining the coil diameter can involve deciding between specifying the Outer Diameter (OD) or the Inner Diameter (ID), both of which can affect the fit in your assembly. The Free Length (FL) of the spring is its length without any load and is critical for ensuring the spring can accommodate the desired travel distance in your device. The Number of Coils (N)—both active and total—determines how much the spring can deflect before bottoming out (in the case of compression springs) or how much torque it can provide (in torsion springs). The spring index (C), calculated as the ratio between the mean coil diameter (D) and the wire diameter (d), influences manufacturing feasibility and stress distribution. A spring index that’s too low or too high can make the spring difficult to produce reliably or prone to defects. All these dimensional factors interconnect, so modifying one parameter may require readjusting the others to maintain the spring’s performance targets.
Using Online Tools for Faster, More Accurate Spring Design
Spring Creator 5.0
To simplify the process of designing and selecting a custom spring, you can use specialized tools like Spring Creator 5.0 by Acxess Spring. This online platform streamlines calculations that would otherwise be performed manually, significantly reducing the chance of arithmetic mistakes. After you input your basic requirements—such as wire diameter and outer diameter—the software instantly provides key metrics like spring rate, max load, and max travel. Spring Creator 5.0 also includes material databases that make it easy to select or compare different alloys, helping you quickly see the trade-offs in cost, maximum load capacity, and max shear stress. Additionally, a visual component often shows you how changing one dimension (like wire diameter) affects other parameters (like maximum load), making it simpler to iterate through various design scenarios before settling on the optimal combination.
Online Spring Force Tester
The Online Spring Force Tester (OSFT), developed by Acxess Spring, is a cutting-edge, web-based application designed to address the growing need for precise, reliable, and efficient spring testing methods. Unlike traditional approaches that rely on bulky, expensive equipment and specialized training, the OSFT offers a user-friendly platform for simulating real-world operational conditions. By providing capabilities such as rate testing, travel testing, load testing, and visual simulations, this digital tool equips engineers, designers, and quality control professionals with the data they need to validate spring performance against exacting standards. Its versatile testing functions allow for comprehensive analysis without the time and cost constraints associated with physical testing devices, ensuring that springs used in various industries—ranging from automotive to medical devices—meet stringent safety, efficiency, and longevity requirements.
Using Online Tools
Imagine you require a compression spring with a 1-inch free length, capable of providing 12 lbf when compressed to 0.4 inches. First, you open Spring Creator 5.0 and input parameters like the wire diameter (say 0.05 inches), outer diameter (0.5 inches), free length (1 inch), with 6.75 total coils. You specify Stainless Steel 302 (ASTM A313) for improved corrosion resistance.
The software calculates the necessary spring rate, and it might suggest adjustments—perhaps a slightly thicker wire or more coils—if the stress is too high for your chosen material. If your dimension equals a safe design, you’ll get the page for your custom part number with its own 3D View, 3D CAD, blueprint and Online Spring Force Tester, all created for you in just a few seconds. In this example, we get Custom Spring Part Number AC055-500-6750-SST-1000-C-N-IN.
Once satisfied with the design, you can test if . Go to the Online Spring Force Tester tab and input your desired load or travel. If the force matches your target values within acceptable tolerances, you can trust that the spring will perform reliably in your application. If there’s a mismatch, you can loop back with the manufacturer to verify the design, material, and manufacturing process, ensuring you end up with the exact spring performance needed.
Understanding Tolerances and Manufacturing Variances
In any manufacturing process, there will be small variations in dimensions, wire properties, and finishes. Dimensional tolerances define the allowable range around a nominal measurement—this might include ±0.001 inches in wire diameter or ±0.010 inches in outer diameter. Force tolerances indicate how closely the spring’s actual force at deflection must match the specified force, commonly ±10% but sometimes tighter for critical applications like aerospace or precision medical devices. Length tolerances affect the free length or overall compressed height. Communicating desired or required tolerances to your spring manufacturer is essential, as tighter tolerances can raise production costs and extend lead times. However, for mechanisms needing high precision, such as surgical tools or delicate instrumentation, investing in narrower tolerances can mean the difference between flawless operation and repeated malfunctions. Always weigh the cost implications of stricter tolerances against the functional advantages they provide in your final application.
Ensuring Quality and Performance
Prototyping and Testing
For critical or high-volume applications, creating a prototype run is a wise step to validate your spring design. During prototyping, you’ll check if the spring fits the assembly correctly, if it delivers the required force or torque, and whether it can endure the expected cycle life without signs of fatigue or failure. Testing may involve compressing or extending the spring hundreds—sometimes thousands—of times to simulate real-world usage. You might also expose it to extreme temperatures, humidity, or corrosive substances if those conditions are relevant to your application. The data collected helps you refine your design, tweak the wire diameter or number of coils, and confirm that the chosen material truly meets your performance needs. By catching any shortcomings early, you avoid costly rework or field failures after the product is fully launched.
Surface Treatments and Finishes
Surface treatments can significantly boost a spring’s durability and resistance to environmental factors. Shot peening, for instance, bombards the spring with small, hard particles, creating compressive stresses on the surface that improve fatigue life. Electropolishing or passivation, particularly for stainless steels, can remove surface impurities and enhance corrosion resistance, making the spring cleaner and more stable in harsh settings. Coatings such as zinc plating or powder coating add a protective layer that prevents direct contact between the metal and corrosive agents. In some applications—like medical devices—applying specialized coatings could also ensure the spring remains biocompatible. When deciding on a surface treatment, be mindful that certain finishes can alter dimensions slightly, particularly for very small springs, and may affect the spring’s frictional properties or interaction with other components.
Final Steps: Ordering Your Custom Spring
When you’re ready to place an order for a custom spring, compile a detailed specification sheet that includes the wire diameter, outer diameter, free length, number of coils, material, and any special end types, hooks, or legs. Clearly state the loads at specific deflections or torques at certain angular displacements, so the manufacturer can verify that the design is feasible. If your application needs specialized finishes—like passivation, powder coating, or shot peening—mention these requirements up front. Discuss tolerances for all critical dimensions, along with any performance tests you need the springs to pass. If available, share a CAD drawing or physical sample to remove ambiguity about orientation, coil spacing, and end treatments. When dealing with new or highly complex designs, request prototypes before committing to full production. These prototypes should be thoroughly tested using tools like the Online Spring Force Tester. Once validated, you can confidently proceed with a larger production run. Clear, ongoing communication with your spring supplier at every step is the best way to ensure you receive products that match your expectations for performance and longevity.
5 Essential Tips for Designing Perfect Custom Coil Springs
Developing custom coil springs made to order is a multifaceted endeavor that demands close attention to a range of variables. Below are five essential insights to keep in mind:
- Customized Solutions: Tailor-made springs provide highly specialized answers when off-the-shelf products fall short, guaranteeing the ideal fit and functionality.
- Material Importance: Selecting the right material—be it stainless steel, music wire, or another alloy—directly affects how well the spring performs under different conditions.
- Dimensional Accuracy: Meticulous measurement is critical, and digital tools like Spring Creator 5.0 can significantly streamline and enhance the design process.
- Quality Assurance: Grasping production tolerances and potential variances is crucial; for high-stakes applications, prototyping and thorough testing are highly recommended.
- Effective Communication: Providing your spring manufacturer with clear specifications and maintaining open dialogue helps ensure the final springs align with all design goals.
By concentrating on these core elements, you can maximize the effectiveness and service life of your custom springs. Take the next step in refining your spring designs by leveraging Acxess Spring’s Online Spring Force Tester to validate performance, and use Spring Creator 5.0 to swiftly generate precise, reliable spring solutions.