Yarn and Stitch Size, what’s a girl to do?

I get a lot of emails and Craftsy class questions about stitch size and which yarns are appropriate for what machines. These are important questions because, coupled with the auto tension (see blog 6/5/16), stitch size and yarn choices account for a lot of the problems that beginning machine Knitter’s encounter.

Stitches form the same way on all machines by shunting the needle butts through a triangular pathway in the cams on the underside of the carriage. First the needles are pushes forward in their slots so that the old stitches slide back over and open the latches. Then, right in the middle of the carriage, yarn is fed into each needle hook before the carriage guides them back in their slots. Larger or smaller stitches are formed depending on how far back the needles are pushed. That distance is determined by the length of the triangular pathway which, in turn, is controlled by the dial on the top of the carriage. (If you own a Bond/ISM, the key plates feature fixed triangular pathways of varying lengths)

Stitch size or tension? I know that some manuals use the term “tension” to describe the numbers on the top of the carriage dial and, in all honesty, I have no idea why. Stitches are formed by the length of the pathway underneath the carriage, which is lengthened or shortened according to the numbers on the dial. There is no tension applied to them. To my mind, tension only comes into play when the yarn passes between the two spring-loaded discs in the tension mast to create more or less tension – or drag – on the yarn. I think that using the word tension to describe both the tension mast and the dial settings is confusing.

I use the term stitch size but stitch tension and stitch size are the same thing and they are controlled by the dial (usually) on the top of the carriage. The larger the number, the larger the stitch size and the smaller the number, the smaller the stitch size. This is because the cams under the carriage create a longer or shorter pathway for the needle butts to travel through. When the butts travel a longer distance, they pull more yarn through each stitch.

No single machine is capable of knitting all the yarns you might want to use – which is why so many of us own more than one machine. Every machine is capable of handling a very specific range of yarns and that is determined by a couple of things. First of all, the yarn needs to be in some proportion to the needles themselves: the size of their open hooks and its size when the latch is closed for the old stitch to slide off over a new one. Stitches must must be able to cleanly fit into the hooks of the needles so they don’t split and cause damaged stitches or a jammed carriage as the needles move back and forth through them to form the next row of stitches. Obviously, a super bulky yarn will not fit the hooks of a standard gauge machine, but it works the other way as well. If a yarn is super thin, it probably wants to form very tiny stitches and, with the dial set on a very low number, the stitches may be too tight to pass over the closed latches.

The space between the needles also affects stitch size and gauge because, once the fabric is off the machine and you give a good lengthwise tug, the yarn that passed below the sinker posts/gate pegs/flow combs is absorbed into each of the stitches, slightly increasing their size. Sometimes you can use this effect to your advantage if you are trying to match a very specific gauge and happen to own two machines. For example, worsted weight wool usually knits around stitch size 7 on a 6.5 mid-gauge machine and on about a stitch size 5 on most bulkies. While you might be able to achieve the requisite 5 stitches per inch on either machine, you might find that the row gauge of the swatch knitted on the mid-gauge is closer than the one knitted on the bulky because of the way the yarn between the stitches is absorbed into the stitches. You can knit worsted on either of these machines, but you may prefer the hand or the drape of the fabric from one over the other .

The chart below will give you a rough idea of which machines can knit which yarns but these are not iron clad rules. Apart from trying to achieve a specific gauge or drape to your fabric, you also want it to be easy for you and the machine to knit the yarn in question. That said, let me state that there is an optimum range for which every machine is calibrated to work perfectly– the sweet spot, if you will, where the yarns knit pliable, drapey fabrics and neither the machine nor the knitter are strained.

chart
Click to enlarge this chart

Most standard gauge (4.5 – 5 mm) machines are calibrated to knit their best with fingering weight yarn on stitch sizes 5-8 (depending on the brand). Mid-gauge (6.5 – 7mm) were designed specifically for DK weights to knit like butter (or, as we say in Boston, Buttah) on stitch size 5, with a range for other suitable yarns extending from 4-7 or 8. Bulkies were designed for worsted weights to knit on size 5 (More Buttah) and their sweet spotr also extends from stitch size 4-7 or 8.

The sweet spot is where you can knit appropriate yarns with a fair amount of confidence that they will knit cleanly and easily. Yes, of course you can knit with a stitch size 10 but be aware that it is not what the machine was designed to do best, is not what it really likes to do (it is just trying to make you happy)) and will probably be harder to push the carriage across each row. It is definitely not where a beginner should be starting! Ditto for size 3. On size 10, the needle butts are pulled down a longer cam pathway under the carriage, which takes more effort on your part and the machine’s. On size 3, the stitches that need to slide over the closed latches can be stingy and small and almost need too be dragged over the latches.

On the other hand, if you work with yarns that knit in the optimum range for your machine, neither you nor the machine needs too work so hard and you are not setting yourself up for yarn problems when you try new techniques. You’ll have a better idea whether it is something you are doing (or not)) that might cause problems as you experiment with new techniques.

Well then, Susan, why DO they have sizes 1-3 and 9-10 on the dial????? Both extremes on the dial are included basically because they can. The smallest stitch sizes become useful when working ribbing (latched and true) because the idea is to create smaller stitches with more elasticity. When stitches reverse from knit to purl, they create the elasticity that causes ribs to pull in the fabric. When those small stitch sizes are combined with double bed capability, the stitches also access the yarn that zig zags back and forth across the beds from stitch to stitch. That length is absorbed into the stitches so that they are not really as small as they would be if they had been formed on a single bed where the stitches can only absorb the short length of yarn between adjacent stitches.

The largest stitch sizes do allow you to extend the range of yarns that your machine can use, but keep in mind that if you are constantly working on size 9 or 10, you probably need a different machine with a coarser gauge and bigger needles. Also, I would never recommend a beginner to start working on size 10 because they need to develop a feel for when the machine is working smoothly so they begin to understand when things go awry.

I’ll add some more thoughts on stitch sizes and swatching in the next blog post once I get caught up in the garden and give some attention to the current book project and the classes I will be teaching at FIT in the fall. If anyone finds a way to get more hours in the day, please let me know the secret!

Author: Susan Guagliumi

I'm a machine knitter, author, gardener and pretty good cook. I live in Connecticut with my husband, Arthur.

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