Tutorials & How-To's

Set in Sleeves – how to sew sleeves into armholes neatly

If you did a straw poll of knitters, asking them what they hate most about knitting, I would put a lot of money on the most popular answer being seaming. If you dug deeper and asked them to be more specific, I think a fair chunk of those people would say “setting in sleeves”. Does this sound like you? You’re not alone. So many knitters seem to hate sewing in a sleeve. So, as I’m about to release 4 cardi patterns which all have set in sleeves I thought I’d try to alleviate the fear.

I design garments which are both knitted flat (seamed) and in the round (Seamless) and honestly, I find it hard to pick a favourite style – they both suit me in different ways, for me it would be like trying to pick a favourite child to pick just one style to knit in. I’d hate to think that there are people out there who limit themselves to knitting in the round just because of a fear of setting in sleeves. I’m a huge fan of yokes – BIG fan of yokes, however, sometimes, there really is nothing as satisfying as a perfectly shaped sleeve head on your shoulder.

I think a lot of people’s fear of setting in a sleeve comes from their attempts to sew in a set in sleeve in a garment made from a woven (non-stretchy) fabric. This can fill even the most experienced sewer with fear – it’s a really tricky skill to get that sleeve head to fit into the armhole without any puckering. However, what these people seem to forget is just how forgiving knitted fabric is. Both of your seams will stretch and then retract back into place, actually making knitted fabric the best friend of anyone trying to set in a sleeve.

In an ideal world the circumference of your sleeve head will exactly match the circumference of your armhole. But I’ll let you in to a little designer secret here. We actually design the sleeve head to be at least 5% larger than the armhole. Why? Well, basically to try to eliminate the number of knitters who may end up with a sleeve head which is smaller than the armhole. This is the worst outcome you could have, so bear that in mind next time you’re following a pattern which tells you to “Continue straight until armhole measures X” – The designer really does mean “X” and not “X plus a few rows for luck”.

When a sleeve head is smaller than the armhole the tweaking and stretching required to fit it in puckers the armhole of the garment and just looks terrible. However, if the sleeve head is slightly larger than the armhole, then it can be eased in without too much trouble and the resulting shape is actually beneficial and can look very professional, even more professional than a sleeve head which was exactly the same size as the armhole. So, most experienced designers will account for this and make sure the sleeve head is ever-so-slightly larger than the armhole.

So how do I fit this excess fabric into the smaller hole? Good Question. Hopefully the following photo tutorial will help you to master the technique of setting in the perfect sleeve.

The body of this particular garment was made in one piece so there are no side seams. This means that we are truly going to set in the sleeve in the most traditional sense of the technique. Sometimes, when the body of a garment is also seamed you may be instructed to sew the sleeve head into the armhole and then sew the sleeve seam and side seam in one long continuous seam. If so, the basic principles of this tutorial are still relevant.


In this particular example, we start by sewing the sleeve seam. I like to block the sleeves before doing this, particularly these ones as they have pretty lace cuffs which is easier to block flat. Blocking the sleeve before sewing helps to sew the seam neatly as the stitches are more even and do not tend to curl as they would un-blocked.

blocked sleeve
blocked sleeve

The next step is optional for experienced seamers but essential for a beginner. At regular (2-3″) intervals on each side of the sleeve place a piece of scrap yarn. This is essential to help you keep the seam straight. In time, this will become second nature to you but if this is your first time seaming, you will find the guidance helpful.

Place markers at regular intervals on each side
Place markers at regular intervals on each side

Then, beginning at the cuff and using the tail of yarn I had left over from the long tail cast on, I sew the sleeve seam using mattress stitch. Ensuring as I go that the scrap yarn markers match as I go up the sleeve.

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When I reach the top, if I have any of the sewing yarn leftover I don’t cut it, I leave it there to sew the sleeve into the armhole later. But first I have to position my sleeve in the armhole and place scrap yarn guides as before.

The first scrap yarn marker is to mark the centre of the sleeve head and is found by folding the sleeve in half – the centre of the sleeve head is the centre of the BO row at the top of the sleeve. Place a scrap yarn marker here. When we start sewing the sleeve head into the armhole, this will need to line up perfectly with the shoulder seam on the garment.


The next markers are place at the half-way points of the armhole, found by folding the armhole in half and marking the point halfway between the shoulder seam and the centre of the BO Sts at the underarm.

Then, I also mark the halfway points of the halfway points – dividing each side of the armhole into 4 even sections.


Then I do the same with the sleeve head. Mark the halfway point between the marker at the top of the sleeve head and the BO Sts at the bottom of the sleeve head.

Then the halfway points of the halfway point, dividing the sleeve head into 4 even sections on each side.

019 021

Now your prep-work is complete, it’s time to start stitching the sleeve head into the armhole. Let’s go back to the thread at the top of your sleeve seam from earlier. This point corresponds with the centre of the BO Sts at the underarm of the garment. (or, in a seamed garment, the side seam).

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Due to the awkward shape of a sleeve head I find it helpful to place the garment over a pillow for seaming. Some people use their knee – but this can make for awkward sewing posture. Some use the corner of a sofa cushion, but again, I prefer to sew sitting down so I opt for the corner of a pillow which I hold between my knees. This is up to your own personal preference. You might not need any aid at all!

Using mattress stitch, work your way up to the first of your markers, making sure they line up. There are two things to bear in mind here. Firstly, you will have more rows on the armhole side than stitches on the sleeve head side so your mattress stitching will not be 1:1 as it was on the sleeve seam. Every third St, you will need to compensate by going under two bars on the armhole side to one bar on the sleeve head side.


Also remember that the sleeve head may be slightly larger than the armhole which counters a little of this Row-to-Stitch discrepancy but may look to you like the marker on the sleeve head side is further away than the marker on the armhole side. Try your best to neatly account for these discrepancies as you go and ensure that the markers match when you reach them.


When you have reached your first marker, leave the thread and go up to the shoulder seam. Again, using thread left over from the shoulder seam, begin to stitch down from the shoulder seam to the next marker down, on the same side of the armhole you have just worked.


Next, work the top of the armhole on the other side of the sleeve.

Then, work from the underarm (sleeve seam) up towards the next marker on this side of the armhole.

The four most important parts of the sleeve head are now in place. All you have to do now is join the rest of the sleeve head, one section at a time, making sure the markers match as you go.

And Voila! there it is – a perfectly set-in sleeve. (why oh why did I choose to do this demonstration on a garment knitted with a cotton yarn which is so unforgiving??!!) This will probably have taken you a fair bit of time to do but you will get quicker. And besides, you will thank yourself for taking the time to do this properly. We happily spend hours and hours knitting our garments but then we’re reluctant to spend 2 or 3 hours in seaming it, it’s quite crazy isn’t it?!


The same guidelines also hold true if you would prefer to sew your sleeve head into the armhole using backstitch, I just find mattress stitch neater and less bulky and I like to see how the seam is looking from the right side as I go along.

Hopefully I’ve taken a bit of the fear out of setting in a sleeve. Keep your eyes peeled for my 4 new patterns which are due to be published in the next couple of weeks – I’ll announce it here first naturally and I might even be kind enough to give all of you lovely blog followers a discount code………


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