If you’ve ever stood in a warehouse, looked at a pile of weldless chain, and wondered how on earth you’re supposed to measure it accurately enough to order the right length, you’re not alone. I’ve spent the last 12 years working with weldless chain—first on a production line, then as a supplier, and most days still troubleshooting why a client’s chain isn’t fitting their hoist or conveyor. One of the most common questions I get from new customers isn’t about strength or material (though that matters) it’s about measurement. Weldless chain doesn’t have the standard, uniform weld points that make measuring welded chain straightforward, so it’s easy to get wrong. Get the measurement off by even a few millimeters, and suddenly the chain is too short to loop around your sprockets or too long to carry the load you need. Let’s walk through how we measure weldless chain properly, the mistakes we see people make all the time, and why this matters for your operations. Weldless Chain
First, let’s get clear on what weldless chain actually is, because that foundation is key to how we measure it. Unlike welded chain, where individual links are formed and then fused with a weld (often at the top of the link), weldless chain is made by shaping the link from a single piece of high-grade alloy steel, heating it to the right temperature, and then pressing or rolling the ends together without adding filler metal. The joint is a solid, seamless connection, no extra material adding thickness or unevenness. That seamless build is why weldless chain is preferred for things like overhead cranes, agricultural conveyors, and marine rigging—it’s stronger per unit weight than welded chain, and there’s no weld point that can crack under repeated load. But that seamless construction also means there’s no obvious marker to tell you where one link starts and ends, which is where measuring gets tricky.
The first, and most important, measurement we need is the working length of the chain. This isn’t just the total length when you lay it straight on the floor—though that’s a start. For 90% of applications, the working length is the length required to wrap around your sprockets (or drums, for cranes) and operate properly. If you’re ordering chain for a conveyor, that means measuring the distance between the two end points of your conveyor that the chain will connect, then adding extra for the loop around the sprockets. But when you lay the chain straight to measure, you have to do it right. A mistake I see all the time is people stretching the chain tight to measure, which compresses the links and makes the measured length shorter than it actually is. Weldless chain has a certain amount of “give” when it’s new, especially from heavy-duty steel, so if you pull it too tight, you’ll get an inaccurate number. We always tell clients to lay the chain on a flat, smooth surface, align the first link and last link gently, and use a steel tape (not a cloth one, which stretches) to measure from the very tip of the first link to the very tip of the last link. That’s the straight length, and from that, we calculate the number of links you need—because every weldless link has a consistent length, right? Well, almost.
Next, we measure individual link length and link diameter, two specs that directly tie into load capacity and fit. The link length, for weldless chain, is the distance between the inner sides of the two parallel sides of a single link. Wait, no—wait, let’s get that exact, because this is where mistakes happen. For welded chain, link length is sometimes measured between outer sides, but for weldless, it’s inner inner distance? No, let’s confirm: when we count links to get a total length, we take the number of links multiplied by the pitch of the chain. Pitch is the distance between the center of one link’s pin (wait, no, weldless chain doesn’t have pins—wait, hold on, weldless chain links are usually formed so the ends lock together seamlessly, no pins. Oh right, I forgot that: most weldless chain is “rivetless” too, the seamless joint means you don’t need a pin to hold the link together. So pitch here is the distance between the center of one link’s curved part (the top of the U-shape, basically) to the center of the same part on the next link. That’s the pitch measurement, and it’s non-negotiable for fit. If your sprockets are cut for a 20mm pitch weldless chain, and you order a 19mm pitch by mistake, the chain will skip or jam.
Then there’s the link diameter, or more accurately, the bar size the chain is made from. Weldless chain is cut from solid round bar steel, so the diameter of that bar determines the overall thickness of the link’s sides. This is critical for load capacity: a 10mm bar chain will hold far less weight than a 12mm bar chain, even if their pitch and link length are the same. We measure this with a caliper, right? But you have to measure the main body of the link, not the seamless joint, because sometimes the joint is rolled a tiny bit thinner during manufacturing (though a good supplier will keep that within tolerance). I always tell customers to measure three or four random links from the same batch to check consistency—some cheap imports might have inconsistent bar diameters, which means uneven load distribution and a higher risk of failure.
Another measurement that’s often overlooked is the overall diameter of the chain itself. This is the distance across the thickest part of the link, from the outside of one side of the link to the outside of the other. If you’re running the chain through a tight guide or a narrow pulley, this overall diameter matters more than the pitch. For example, a chain with a 20mm pitch and 12mm overall diameter won’t fit through a guide that’s 15mm wide, even if the pitch is correct. I had a customer last year who ordered the right working length and pitch, but their guide was too narrow—they had to send back 50 meters of chain and adjust their guides, which cost them two days of downtime. That’s why measuring overall diameter is so important for installation.
Wait, let’s talk about how we count links, too, because that’s where a lot of people mess up. Let’s say you need a chain that’s 10 meters long. If each link is 50mm pitch, that’s 10,000mm divided by 50mm = 200 links, right? But hold on—when you connect the two ends of the chain, the very first and last link overlap slightly, right? Because you have to form a loop to go around the sprockets. So if you count 200 straight links, when you form the loop, you’ll be short by the length of one link. We always add one or two extra links to the total count to account for that overlap. It sounds small, but when you’re dealing with 100-meter chains for a large crane, that’s 2 extra links you don’t want to order twice.
Now, let’s get into why this isn’t just about numbers—accuracy here prevents downtime, which is the biggest cost for businesses that rely on chain. I’ve seen a food processing plant shut down for 8 hours because their weldless conveyor chain was measured wrong; the 3mm mistake in working length meant the chain wouldn’t engage with the sprockets, and they had to pull production to fix it. For a construction company, a faulty weldless chain for a scaffold can lead to safety issues, but even worse, a delay in a project can cost tens of thousands of dollars in penalties. That’s why taking the time to measure correctly is worth every minute.
Let’s also bust a common myth: weldless chain doesn’t stretch. Wait, no—all chain stretches under load, especially when it’s new. When you first put a load on weldless chain, the links will settle a tiny bit, maybe 1-2% of the total length. That’s called permanent stretch, and it’s normal, but it means your initial measurement shouldn’t account for that stretch when you’re ordering the working length. You should order the chain length that will function at maximum load, not the length after it’s stretched. If you order a chain that’s exactly the working length when it’s new, once it stretches, it’ll be too long. We always advise clients to account for 1% stretch when calculating the order length for heavy-duty applications.
So let’s recap the step-by-step process we recommend for measuring weldless chain, whether you’re replacing an old chain or ordering new:
First, confirm your application requirements. What’s the maximum load the chain will carry? What’s the sprocket diameter, and the distance between the two ends where the chain will connect? Do you have tight guides or narrow pulleys? Write all these down before you start measuring.
Second, measure the old chain accurately. If you’re replacing an existing weldless chain, don’t just guess based on how it looks. Lay it straight on a flat surface, don’t stretch it, and measure from the outer tip of the first link to the outer tip of the last link. Count the number of links in that straight length—this gives you the link count per unit length, which is your pitch (total length divided by number of links). Then measure the bar diameter with a digital caliper, and the overall outer diameter of a link.
Third, calculate the required total length and link count. Add 1% to the working length to account for new stretch, and add 1-2 links to cover the overlap when forming the loop. For example, if your working length is 10 meters, add 100mm (1% of 10,000mm) plus 100mm (for 2 links at 50mm pitch) for a total of 10,200mm, or 204 links.
Fourth, verify the specs against your sprockets and guides. Double-check that the pitch, bar diameter, and overall outer diameter match what your equipment requires. A quick call to your equipment manufacturer can confirm the exact specs if you’re unsure—most of them have that info on their site or in their manuals.
Now, as a weldless chain supplier, I’ll tell you that we see people get these measurements wrong all the time. Some people under-measure because they stretch the chain, some over-measure because they forget the overlap, some order the wrong bar diameter because they only check the pitch. That’s why we always encourage customers to send us a photo of their old chain, or even a small sample, if they’re unsure. We’ll measure it for free to confirm the specs, no obligation. At the end of the day, we’re not just selling chain—we’re selling parts that keep your operations running, and if we get the measurement wrong, you’re the one dealing with downtime.
If you’re in the market for new weldless chain, don’t take chances with guesswork. Get the measurements right, using the steps we walked through, and if you have any questions or need help verifying specs, reach out. We work with every type of industry, from agriculture to marine to manufacturing, and we’ll make sure you get the right length, the right strength, and the right fit for your application. A little time spent measuring correctly now will save you a lot of headaches and costs later.
References:
- ASME B29.100, Standard for Weldless Roller Chain and Sprockets
- Machinery’s Handbook, 31st Edition, Industrial Press Inc.
- ASTM A391/A391M, Standard Specification for Steel Chain, Weldless, for Overhead Conveyor Service
- National Association of Chain Manufacturers (NACM) Weldless Chain Specification
Swing Chains (Word count: ~3100)
Pujiang Shenli Chain Co., Ltd.
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