Military Spring Manufacturer
Since 2004, Coiling Technologies, Inc., has put a lot of emphasis on developing high-quality military suspension springs. We use the same effective, fast, and economical technologies to produce mil-spec springs that we do on all our other models to ensure reliable performance.
At Coiling Technologies, Inc., we have designed and manufactured hundreds of thousands of military suspension springs for numerous U.S. government vehicles as well as for U.S. allies. Our springs are in service in military aircraft, vehicles, and vessels around the world.
Materials for Military Springs
Military springs must withstand extreme conditions while maintaining the equipment’s operational readiness. This requires the use of high-performance materials, including carbon steel alloys, super alloys, and specialized materials. Some examples of the materials we use on mil-spec springs include:
- Alloy steels chrome silicon, 5160H, and 51CrV
- High-performance nickel alloys Elgiloy®, MP35N, and NIMONIC® 90
- Inconel 600, Inconel 718, and Inconel X750
- Stainless steel
The correct material depends on the intended application for each spring. For example, metals used for marine springs must possess corrosion resistance and the ability to withstand low temperatures. These requirements make metals such as stainless steel, with its high strength, corrosion resistance, and resistance to low temperatures, an ideal choice.
Premium Springs for Demanding Applications
Military springs must provide dependable service through a variety of demanding conditions. Our engineers consider those conditions during the design and fabrication process. Special considerations for military springs include:
- Military and MRAP springs require more augmentation suspensions as they carry a heavy load.
- Springs on military vessels must consist of materials able to withstand corrosive saltwater environments.
- Aircraft springs require materials and design features that can withstand extreme temperatures and high pressure.
Additionally, all military springs must meet extremely tight tolerances and comply with all applicable DoD standards and requirements. To accommodate these conditions, our engineers design military springs in such a way that they can withstand extreme loads, stress, and corrosive conditions without failure.
Types of Military Springs
Our mil-spec springs are in use in aircraft, Humvees, military transport vehicles, tanks, ships, and submarines for all branches of the U.S. military. A few of the types of military springs we can design include:
- Aircraft nose cone and landing gear springs
- Emergency medical vehicle suspension springs
- Humvee suspension springs (HMMWV)
- Military transport vehicle suspension springs
- MRAP’s suspension springs
- Ship hatches, lids, and access panel springs
- Tanks suspension springs
- Troop carrier suspension springs
We can produce springs to your existing designs or leverage CTI's engineering staff for a completely engineered spring solution.
Custom Designed Mil-Spec Springs
Our team at Coiling Technologies, Inc., includes dedicated engineers and fabricators to design and manufacture custom mil-spec springs to meet demanding applications. Our facility is ISO 9001:2015 certificated, highlighting our commitment to quality. Contact us online or call (800) 969-2645 to request a quote.
Military Suspension Springs FAQs
What military spring work does Coiling Technologies specialize in?
Military suspension springs are the stated specialty. CTI's page says the company has put emphasis on developing high quality military suspension springs since 2004, and has designed and manufactured hundreds of thousands of them for numerous U.S. government vehicles and for U.S. allies, with springs in service in military aircraft, vehicles, and vessels. Named types include Humvee (HMMWV) suspension springs, MRAP suspension springs, military transport and troop carrier suspension springs, tank suspension springs, aircraft nose cone and landing gear springs, emergency medical vehicle suspension springs, and ship hatch, lid, and access panel springs.
Is Coiling Technologies Mil-Spec certified, ITAR registered, or DFARS compliant?
The certification CTI holds is ISO 9001:2015, audited regularly. There is no Mil-Spec certification, ITAR registration, DFARS compliance registration, or DLA and QPL source listing to represent, and none of that should be inferred from the term "mil-spec springs" as the site uses it, which describes a product category rather than an approval CTI carries. Military specifications named on your drawing are handled as build and heat treat requirements that CTI manufactures to and documents against. If your contract flows down a specific registration at the spring supplier level, raise it in the RFQ.
Why do military suspension springs need higher load capacity than commercial ones?
Armoring and mission equipment add weight the original chassis was never sized for, and the suspension has to absorb it without bottoming out or losing ride height. CTI cites the HMMWV up-armor program, where gross vehicle weight rating increased by more than half because of the added armor. A spring rated for the base vehicle cannot carry that. Rate has to rise, and wire or bar section rises with it, which is why heavy duty and large section capability is a stated CTI specialty. MRAP and augmented suspension work follows the same pattern.
How do shock and vibration loading affect military spring design?
Wheeled and tracked vehicles operating off road generate load spikes well above static, arriving as short duration impacts rather than smooth cycles. The design has to cover peak stress at full compression without taking a permanent set, and cover the fatigue damage that thousands of those events accumulate. Coil clash, buckling under side load, and end coil fretting all appear under shock service and none of them show up in a static calculation. Shot peening raises fatigue resistance by putting the wire surface into residual compression. Provide the load spectrum and travel limits, not just the static load.
What materials does CTI use for military springs, and how does environment drive that choice?
The published list includes alloy steels chrome silicon, 5160H, and 51CrV, high performance nickel alloys Elgiloy, MP35N, and Nimonic 90, Inconel 600, Inconel 718, and Inconel X-750, and stainless steel. Environment decides which one. Marine and shipboard springs need corrosion resistance and low temperature toughness, which favors stainless and nickel alloys. Aircraft springs need temperature and pressure capability. Ground vehicle suspension springs are governed by load and fatigue, where high strength chrome silicon and 5160H are the standard answers, usually with a protective finish. Powder coating and shot peening are both in-house services.
How is corrosion handled on springs going into field or marine service?
Two routes exist and most parts use both. Material selection comes first, since a stainless or nickel alloy resists chloride attack in a way that a coated carbon steel spring cannot once the coating is breached. Coating comes second, and CTI applies powder coating in house. The detail most often missed is that corrosion and fatigue interact. A pit on the wire surface becomes a stress concentration and a crack initiation site, so a spring that would have reached its cycle count in dry service fails early under salt spray. Specify the exposure so material and finish get chosen together.
What documentation and traceability can CTI provide on government work?
The available package covers material certifications with chemistry and mechanical property data, dimensional inspection reports listing measured values against drawing tolerances, first article inspection documentation, load test data, and traceability from the finished spring back to the incoming raw material lot. Because coiling, heat treating, non-destructive testing, finishing, and inspection all happen in the Houston facility under one ISO 9001:2015 system, the lot record does not have to be assembled from several outside vendors after the fact. Government and prime contractor requirements vary by program, so list the required reports and their governing revisions in the RFQ.
Can CTI reproduce a legacy military spring with no drawing?
Yes, and it is common on sustainment work where the original drawing is gone or the original supplier no longer exists. CTI can reverse engineer from a physical sample, and any dimensional or load data you hold narrows the work considerably. A worn sample needs interpretation rather than measurement alone, because free length, wire diameter, and set can all have shifted in service, so the target load and deflection matter more than copying the part as found. The engineering team can also develop a full design from performance requirements when no sample and no drawing exist.
