Same Weight, Different Outcome: Yarn Secrets for The Circular Knitting Machine

If you’ve ever worked on a circular knitting machine, you’ve probably experienced some projects turning out beautifully while others seem to go sideways, despite using yarns that are labelled the same weight. Recently, I ran into this myself. I used three different yarns that were all the same yarn weight—organic cotton, recycled cotton, and Lyocell. The results varied drastically. The Lyocell yarn turned out awfully, while the organic and recycled cotton performed much better. I used the same tension and technique. So, what’s going on?

Here’s why yarns of the same weight can behave so differently on a circular knitting machine.

Fibre composition affects stretch and drape

Even if yarns share the same weight, the type of fibre used can have a massive impact on how they interact with your circular knitting machine. Different yarns have varying levels of elasticity, flexibility, and drape, which can affect how the yarn moves through the machine.

Lyocell is a fibre made from wood pulp, and while it’s known for being silky and soft, it lacks the elasticity of fibres like cotton or wool. This reduced stretch means it can struggle to move smoothly through the machine’s tension guides and stitch formation process. As a result, your fabric may come out uneven or warped, as the yarn doesn’t have the give needed to maintain consistency under the same tension settings.

Organic cotton and recycled cotton, on the other hand, tend to have more natural flexibility and softness. While cotton isn’t highly elastic, it still has enough give to adjust to the machine’s mechanisms more effectively. This allows for more even stitch formation and a smoother final fabric.

Yarn smoothness and the circular knitting machine

The surface texture of the yarn also plays a big role in how it behaves on a circular knitting machine.

Lyocell has a very smooth, almost slippery texture. While this gives the fabric a beautiful sheen and drape when hand-knitted, it can cause issues on a knitting machine. The smooth fibres might slide through the machine unevenly or become caught, leading to inconsistent tension or even dropped stitches.

Cotton Yarns—especially organic and recycled cotton—are typically less smooth and have more grip. This texture makes it easier for the machine to grab the yarn evenly and form consistent stitches. Even if the yarn isn’t as smooth as Lyocell, its slightly more textured surface works in its favour on a circular knitting machine, creating more uniform results.

Yarn construction

Even if two yarns share the same weight, the way they are constructed can lead to different results.

Lyocell Yarn is often smoother and has fewer plies (strands twisted together), or may have a looser ply structure. This can contribute to less stability when moving through the knitting machine, causing stretching or misalignment in stitch formation.

Cotton Yarns, especially recycled or organic versions—are often spun with multiple plies that are tightly twisted. This gives the yarn more structural integrity, making it better suited for machine knitting. The tighter the twist, the less likely the yarn is to lose its shape or tension as it moves through the machine.

Circular knitting machine sensitivity

Finally, knitting machines, especially circular knitting machines, can be surprisingly sensitive to slight differences in yarn properties.

Lyocell’s smoothness and lack of stretch might cause it to slip through the tension disks more easily, leading to inconsistencies in stitch size. Cotton yarns, with their slight grip and flexibility, are easier for the machine to handle, especially under consistent tension settings. The result is more even stitches and a more uniform fabric.

How to improve your results with different yarns

If you’re set on using a yarn like Lyocell, which can produce subpar results on a knitting machine, there are a few adjustments you can make:

• Experiment with tension settings. If a yarn feels too slippery, tightening the tension can help control it more effectively.
• Use a yarn lubricant. This can help improve yarn movement through the machine and minimise any snagging or slipping issues.
• Knit in a different environment. Reducing humidity could help Lyocell behave better on the machine, preventing it from absorbing too much moisture and stretching out of shape.

Conclusion

The same yarn weight doesn’t guarantee identical results when machine knitting because fibre composition, surface texture, moisture absorption, and yarn construction all impact performance. While organic and recycled cotton perform predictably under a set tension, Lyocell’s properties make it more challenging to work with on a circular knitting machine.

Understanding these differences allows you to tweak your settings or make informed choices about which yarns to use, ensuring your machine-knitted projects turn out as planned. As with most things, it is a case of trial and error to see what works for your particular machine.

Here is a video of how to make easy ear warmers on a circular knitting machine.

Happy crafting!