How To Measure Chain Stretch

When it comes to routine maintenance, roller chain is one of the most neglected system components due to its inexpensive cost value. Because they are commonly covered by guards, too, they often fall ‘out-of-sight, out-of-mind,’ only becoming a priority once the chain starts acting up and making noise.

However, proper roller chain maintenance might be more important than you think. “Roller chain is a key component to a bigger system and can end up costing you a lot of downtime down the road if you neglect it,” says Tim Zerger, IBT Director of Bearings and Power Transmission.

Learning how to identify, measure and prevent the common wear-and-tear in even the smallest, most inexpensive parts of your systems can help keep your operations running smoothly, longer.

What Is Chain Stretch?

The name ‘chain stretch’ is actually fairly misleading. Contrary to popular belief, the chain isn’t stretching at all. “The real name is chain elongation,” says Zerger, “It occurs when the chain articulates as it goes around the sprocket and pin wears on the bushing to the point that the length of the pitch elongates.”

How To Measure Chain Stretch

Chain Stretch Gauge

Image Courtesy of Timken Drives

According to Timken Drives’ Drives Product Manager, Richard Neuhengen, “Chain is defined to be worn out when it has grown by 3% of its original length, it’s at this point that one will have to replace the sprocket, also.”

Luckily, there’s an easy solution to measure whether or not your chain has worn, or your chain has ‘stretched,’ without removing the chain from the sprockets. Timken Drives offers an EZ Chain Wear Gauge that measures the distance between two roller links, in-place, by dropping it down between them.

All you need to know is the standard dimensions of your chain, and its tapered design will do the rest with these four, easy steps:
**Note: All tag out procedures should be followed prior to measuring the chain

  • Identify chain pitch size.
  • Locate the corresponding step on the gauge.
  • Check gauge for fit between any two roller links. (Do this with chain in tension.)
  • If the gauge step fits through the checkpoint, the chain is worn out and needs to be replaced. (Gauge should be in line, directly below any outside link plate.)

Made from tough steel, this gauge accurately checks up to nine sizes of American Standard roller chains. “It’s my number one recommendation for chain stretch measurement because it’s easy to use and you can’t mess it up. It either goes or it doesn’t,” Zerger says.

How To Prevent Chain Stretch

Observation and effective lubrication.

When a chain gets rained on, dirty or dusty, the lubrication barrier will quickly diminish if not reapplied regularly. “If you’re not paying attention to your chain━how it’s wearing, how it’s stretching and how it’s lubricated━you’re damaging both your chain and your sprockets,” says Zerger.

Other benefits of effective lubrication? “Cushions impact loads, rust prevention, dissipates heat, flushes away contaminants,” and according to Neuhengen, “Properly lubricated chains can last more than 100 times as long as poorly lubricated chains.”

About IBT’s Bearing & Power Transmission Group

Mechanical Power Transmission has been a cornerstone of the IBT Industrial Solutions business since the company was founded in 1949. If you’re looking for the knowledge and expertise you need to keep your applications up-and-running, contact Tim Zerger, the Bearing and PT Business Group Director at IBT Industrial Solutions, or give us a call at 913-677-3151 to learn more.

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