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These tips for circular knitting machine socks will help you understand the limitations of knitting socks on a Sentro or Addi circular knitting machine and what you can do to make those socks better.
This isn’t a post about knitting machines that are designed to knit socks, which use sock yarn and are generally quite expensive. If your feet are the right size you can make passable socks on a circular knitting machine, and if you know how to knit with needles you can make them even better.
The Limitations of Circular Knitting Machine Socks

The most basic way to knit socks on a circular knitting machine is to use a Sentro 22 or Addi Express 22 (or other 22 pin machine) using worsted weight yarn and knitting a tube sock. This is a really quick and easy project because you’re just making a tube and closing off one end.
The obvious problem with this is that you can basically get one size of socks out of this machine. The size will vary a little depending on the yarn you use, the tension on your machine and how long you knit the tube, but in terms of width there’s not a lot you can do to alter the size.
I’ve heard people looking for tips for circular knitting machine socks say their socks look like fishnets and it’s because they need to stretch a lot to fit their particular feet.
I have relatively small feet (I wear size 8 US shoes) and circular knitting machine socks fit me reasonably well. I wear them around the house almost like slippers.
Tips for Knitting Circular Knitting Machine Socks
Having to use worsted weight yarn instead of sock yarn to make socks on a circular knitting machine is another limitation. Sock yarns typically include nylon, which makes the yarn more durable.
Of course if you’re just wearing the socks around the house and not in shoes, durability might not be as big of an issue. I’ve only made socks on the Sentro using 100 percent acrylic yarn (the originals were Lion Brand Heartland; these are Big Twist from JoAnn), but a wool yarn or wool blend would also be a great choice.
If you have a yarn with a bit of nylon in it, so much the better. Berroco Vintage, for example, is a blend of wool, acrylic and nylon that would probably wear better for socks if you want to use them as boot socks. Check out some of my favorite yarns for use on the Sentro and other circular knitting machines.

Use waste yarn to start your sock. This way you can rip out the cast on and pick up full stitches to bind off the top of the sock.
Make sure you use a loose bind off (Jeny’s surprisingly stretchy bind off is a good one) so you can get the sock over your foot.
The last part you crank should be the toe of the sock. You can pull the stitches tight like you would for the top of a hat, pull tight and sew down like I did for my tube sock, or, if you can knit, you can shape the toe and finish it like you would a hand knit sock.
Likewise you can add a heel and/or ribbing at the top of the sock. Check out the how to for these tips for circular knitting machine socks below.
Also play with the length of the foot and the leg (or the full length if knitting a tube sock). My tube sock was 105 rounds, which is really long. The socks shown here are only 50: 20 for the leg and 30 for the foot. With the addition of the heel and the toe my foot is about 7.5 inches/19 cm long, and the leg is 5 inches/12.7 cm.
My ideal sock would probably be a little longer, but these aren’t too bad. And you can always rip it out and try again if you don’t like the fit.
Knitting a Toe for a Sentro Knit Sock
I think the best easy improvement for a sock worked on a circular knitting machine is adding a hand knit toe. If you know how to knit it’s really easy and fast, and it improves the feel of the sock on your foot.

When you are done cranking your sock, pick up all the stitches on two double-pointed knitting needles. I’m using size 7 US/4.5 mm needles, but 8/5mm would work, too.

You can use another needle to help you pull the stitches off the machine.

Using a third needle to work the stitches, knit 1, slip, slip, knit, knit to the last 3 stitches on the needle, knit 2 together, knit 1.

Repeat on the other needle. 4 stitches have been decreased for a total of 18.

Knit 1 round.

Repeat the decreases. 14 stitches remain.

Try on the sock and see if you need it to be longer. If so, knit another round before decreasing again. I just went straight into the decrease, leaving me 10 stitches.

Graft the toe closed.
Adding an Afterthought Heel
Adding a heel to your circular knit sock is almost as easy as adding a toe, but it does require a little preparation.
I said above my leg was 20 rounds and my foot 30, and I know that specifically because I added the heel after round 20.

To do this you’ll need another piece of waste yarn. Once you’ve cranked the number of rounds you want for your leg, add in the waste yarn as you would change colors.
Crank 11 stitches in the waste yarn (half the stitches).

Leaving a long loop of yarn inside the sock, bring the working yarn into position. You could also cut it, leaving a tail where you joined the waste yarn, and pick it up again, leaving a tail on the other side. This just seemed faster. You’ll still cut it and weave the ends separately later.
Continue in the working yarn for the length of the foot. Finish the toe as above.

When you are ready to work the heel you’ll find that row of 11 stitches worked in waste yarn.

Unpick the waste yarn and put the live stitches onto two double pointed knitting needles (11 from each side). You can slide the needle into the stitches before you remove the yarn, or pick the stitches up as you go.

If you pick up the stitches and they are on the needle backwards (you can tell because the loop is twisted and it’s hard to knit from the front), knit through the back loop on the next round to untwist them.

I like to pick up an extra stitch at each end of each needle and knit it together with the stitch next to it (first or last on the needle) to help close up the gap, but you can also close any hole when you weave in your ends.

After knitting that first round, knit 1, slip, slip, knit, knit to 3 stitches from the end of the needle, knit 2 together. knit 1. Repeat on the other needle. 18 stitches remain.

Knit 1 round.

Repeat these 2 rounds, then do the decrease round again. 10 stitches remain.

Graft the heel closed.
Adding Ribbing to a Circular Knitting Machine Sock
Another good tip for circular knitting machine socks is to add ribbing to the top of the leg.
This helps the sock hold onto your leg a little better and just gives it a finished look.
Here we’re working from the cast on edge, which should have waste yarn.

Pick up the stitches from the first round of the working yarn using two double pointed knitting needles.

Unpick the waste yarn.

Using a third needle to work the stitches, knit 1, purl 1 repeating across the round.

Work this round as many times as you like for the amount of ribbing you want. Mine is about 1.5 inches/3.8 cm.

Bind off very loosely.

Do you have any tips for circular knitting machine socks I missed? I’d love to hear them!
