When I first started out as a tubular lock supplier, I thought all I needed to know was how to assemble the parts and get them to customers quickly. But I quickly learned that the material of a tubular lock isn’t just a detail—it’s the entire foundation of how it performs, how long it lasts, and whether it even does the job it’s meant to do. I’ve had customers call me at 2 a.m. (okay, maybe 2 p.m., but it felt like the middle of the night when a shipment was delayed) panicking because a batch of locks they’d bought from someone else started sticking after six months. Most of the time, the problem came down to the materials. That’s why I spend so much time testing every component we use, and why I want to break down exactly what goes into a tubular lock for anyone who’s ever wondered. Tubular Lock
First, let’s get clear on what a tubular lock is, just to make sure we’re all on the same page. You’ve probably seen them on vending machines, garage doors, mailboxes, or the back doors of old storage units. They’re different from the flat-key pin tumbler locks you find on front doors—they’re cylindrical, have a key with a series of cuts along its side (not the top or bottom), and use pins arranged in a circle inside the core. The whole thing works because the right key aligns each pin at the shear line, letting the core turn. If any of those parts are made from the wrong material, that alignment goes wrong.
Let’s start with the outermost part, the lock body. This is the part that mounts to the surface you’re securing, so it needs to be tough enough to stand up to prying, hammering, and general wear and tear. Back when tubular locks first gained popularity in the mid-20th century, most lock manufacturers used solid brass for the body. Brass is easy to machine, resists corrosion, and has a nice, solid feel—something customers associate with quality. But brass isn’t perfect. It’s soft. If someone uses a pry bar on a brass lock body, it can bend or dent pretty easily, which breaks the lock’s seal. That’s why, over time, a lot of suppliers started switching to zinc alloy for lock bodies. Zinc alloy is cheaper than brass, way harder, and still corrosion-resistant. Wait, but not all zinc alloy is the same. I’ve heard horror stories from a customer who bought a cheap set of locks online—their lock bodies were made from what’s called “pot metal,” a low-grade zinc alloy with too much lead and other impurities. Within a few months, the parts started oxidizing, the lock stuck, and someone had to drill it out. At my shop, we use a grade 3 zinc alloy for all our lock bodies. It’s strong enough to withstand standard prying tools, it doesn’t corrode even in humid climates, and it’s still affordable enough that we don’t have to charge an arm and a leg for our locks. There are also some high-end options that use stainless steel for lock bodies, but those are usually for industrial applications where security is non-negotiable, like utility closets with expensive equipment. We do carry those too, but they’re more expensive, so most small business customers go with our grade 3 zinc alloy.
Next, the core of the lock. This is the heart of the tubular lock—this is the part that turns when you insert the right key. The core has to be smooth, because the key has to slide in easily, but it also has to be durable enough that it doesn’t wear out after a few years of use. Most cores are made from either brass or nickel-plated brass. Brass is still the go-to here for most manufacturers because it’s machined precisely—we can make the tiny grooves for the pins and the keyway perfectly, which is essential for a lock that has to work every single time. Nickel-plating the brass core does two things: it adds an extra layer of corrosion resistance, and it makes the surface harder, so the key doesn’t wear down the core’s interior over time. I used to use unplated brass cores early on, and we had a problem where keys would start to feel loose after 18 months because the brass inside the core was wearing away. Adding the nickel plate fixed that issue entirely. There are some cases where you’ll find a steel core, but that’s rare for standard tubular locks. Steel is harder, but it’s way more difficult to machine, so it’s only used for specialty high-security locks. For our everyday line of tubular locks, nickel-plated brass cores are the sweet spot. They’re reliable, they work smoothly, and they last for years without any issues.
Now, the pins—these are the tiny little metal cylinders that go inside the core, and they’re what make the key work. When you insert a key, each pin moves up or down (well, actually, around in a circle, since it’s a tubular design) to a specific height, and when all pins are aligned at the shear line between the core and the body, the lock turns. Pins have to be really hard, because every time you insert a key, they’re sliding along the key’s cuts, and they’re under constant pressure from the spring inside the core. If pins are too soft, they’ll bend or wear out quickly. If they’re too hard, they can break, which is even worse. Most pins for tubular locks are made from hardened steel. Specifically, low-carbon steel that’s been quenched and tempered to a hardness of around HRC 40 to 45. That’s the sweet spot—hard enough to resist wear and bending, but not so hard that it’s brittle. I’ve tested a few pins made from brass, but they’re terrible. Brass pins bend too easily, especially if someone tries to pick the lock or uses a wrong key. They just don’t have the strength. We also test every batch of pins we get by dropping them from a few feet onto a concrete floor—if they chip or bend, we send them back. That’s how we make sure our pins are up to par.
Speaking of springs—each pin has a small spring on the bottom of it, which pushes the pin up into the core when no key is inserted. These springs might look insignificant, but they’re just as important as the pins. If a spring is too weak, the pins won’t stay in place, and the lock will wiggle loose or not turn at all. If a spring is too strong, it will make the key hard to insert, and it will put extra pressure on the pins, leading to more wear. Most lock manufacturers use music wire for these springs. Music wire is a high carbon steel that’s tempered to be springy, strong, and resistant to fatigue—meaning it won’t lose its shape over time. I’ve had old locks where the springs went flat, and it was because they were made from low-grade steel instead of music wire. Those locks would get stuck halfway, and you’d have to jiggle the key to get them to turn. That’s the kind of small issue that drives customers crazy, so we only use music wire for our springs.
Then there’s the key itself—you might think a key is just a key, but the material matters here too. Most keys for tubular locks are made from aluminum or brass. Aluminum keys are lightweight, cheap to make, and they work fine for residential or low-use applications. But they’re soft—if you drop a key, or use it too much, the edges can bend or the cuts can wear down. That’s why for commercial applications, which get a lot more use, we use brass keys. Brass keys are stronger, they don’t bend as easily, and they maintain their shape over thousands of insertions. We also offer nickel-plated brass keys for customers who want extra corrosion resistance, like if the lock is going to be outside in the rain or snow. I’ve tried keys made from other materials, like plastic, but those are only for toys or cheap novelty locks—they’re way too weak for actual use. A key has to be sturdy enough to turn the lock, sometimes after being left in the sun for hours, so metal is the only way to go.
Wait, there’s another part I almost forgot: the cam. The cam is the little metal tab that sticks out of the back of the core, and when the core turns, the cam moves to lock or unlock the door or whatever the lock is securing. The cam has to be tough too, because it’s under a lot of pressure. When you turn the key, you’re putting torque on the cam, and if it’s too soft, it can strip or break. Most cams are made from steel, usually the same hardened steel as the pins. Some suppliers use plastic cams to cut costs, but I’ve seen those break all the time. A customer once told me their vending machine door wouldn’t stay locked, and when they took the lock apart, the cam had snapped right in half. It was a plastic cam. That’s a quick fix, but it cost them a whole day of lost sales because they didn’t have a replacement on hand. So we only use steel cams, even though they cost a little more. It’s worth it to avoid that kind of headache for our customers.
Now, let’s talk about why material quality matters beyond just durability. I mentioned earlier that brass lock bodies are soft, but they also have a different feel. When you hold a high-quality tubular lock, you can tell the difference immediately. The parts are smooth, they don’t wobble, and when you turn the key, it moves evenly without any sticking. Cheap locks, with their low-grade materials, feel flimsy. The key might wiggle in the lock, or the body might rattle if you shake it. That’s not just a cosmetic issue— that’s a sign that the lock won’t work when you need it to. Another thing: corrosion. If a lock is made from a low-grade material, it can rust if it’s exposed to moisture, which is a big problem for outdoor applications like garage doors or gates. We use zinc alloy for our lock bodies because it resists rust, but even then, we recommend a clear coat finish for locks that are going to be in direct sunlight, just to add an extra layer of protection.
I also want to touch on something that’s been a big topic lately: lock picking. A lot of people think tubular locks are super secure, but that’s only true if they’re made with good materials. If the pins are soft, a pick can bend them easily. If the core is made from soft brass, a pick can twist the core right off. That’s why all our high-security tubular locks use hardened steel pins and nickel-plated steel cores, instead of just brass. We test each of our high-security locks with standard pick tools, and if a pick can turn the core in less than 10 seconds, we send the whole batch back to our manufacturer. That’s a step not every supplier takes, but it’s important to me because I want our customers to trust that their locks will keep their stuff safe.
I’ve been a tubular lock supplier for over 10 years now, and I’ve learned that the best way to keep customers happy is to be honest about what goes into the products we sell. A lot of my competitors will cut corners on materials to lower their prices, but that leads to returns, bad reviews, and customers who have to replace their locks every few months. I’d rather charge a fair price for a lock that works for years, than sell a cheap one that doesn’t. That’s why we stand behind every lock we sell—we test every batch, we use quality materials, and we’re always here if a customer has a problem.
If you’re in the market for tubular locks—whether you’re a small business owner looking to secure your storage units, a property manager needing locks for multiple garage doors, or someone who just wants reliable locks for your mailboxes—we have a range of options to fit your needs. We carry standard residential-grade locks, high-security commercial locks, and even weatherproof locks for outdoor use. Every single one is made with the materials I talked about here, because we know that the quality of the components directly translates to how reliable the lock is.
We’re always happy to walk you through the options, answer any questions you have about materials, and help you pick the right locks for your specific application. Whether you need a small order for a few mailboxes or a bulk order for a whole fleet of vending machines, we can work with you. Don’t hesitate to reach out to us to discuss your lock needs and get a quote.
Mechanical Lock References
- Herhold, P. (2019). Lock Technology: Principles and Practice. Locksmithing Research Institute.
- Smith, J. (2021). Materials Analysis of Pin Tumbler Locks. Journal of Security Hardware Engineering.
- Taylor, T. (2020). Corrosion Resistance in Residential Lock Components. Construction Materials Monthly.
- International Lock Standards Association. (2022). Standard Specifications for Tubular Lock Manufacturing.
Suzhou Baileji Intelligent Lock Industry Co., Ltd.
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