Inserting sleeves into armholes often needs sewing together different shape curves – outward curve of sleeve, inward curve of armhole. Many people find this challenging.
If so, develop skills by working through a sequence of sleeve-adding techniques.
These aren’t alternate techniques which can all be used on the same pattern. They need different patterns :
– dolman/ batwing,
– raglan,
– square underarm,
– cut-on,
– set on flat,
– set-in in the round.
I’ve put them in the order in which they add new skills.

This post just includes the common basic armholes. There are several more, these are some :
– several ways of making a square armhole (such as Fit For Art, Kwik Sew 3377).
– or add a gusset – typically : add one into a square underarm, or into a slash in a cut-on sleeve underarm (see Gusset on Techniques page.

Many sleeves have gathered versions, which I haven’t shown.
Apart from doing the gathering, gathered sleeves tend to be easier to insert as fit accuracy is not so crucial to getting a good looking result.

More options for sleeves in this pinterest board.

Your own pattern making
For the first four armhole types : examples show how easy it is to make your own patterns.
With flat-set and in-the-round sleeves, they look and feel better if the fit is good. As the curves of the fabric pieces are different, it is much more complex to develop a pattern. And essential the stitching lines match. Instead get some frankenpattern skills (combine sections from several patterns), so you can use armholes and sleeve caps from other patterns that you already know work well !

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Dolman/ batwing
batwing top
image source

Avoid sewing an armhole seam altogether ! The ‘underarm seam’ may go straight from waist to elbow. I tend to forget this style exists because these sleeves are very unflattering on people with larger hips than bust, but they are usually very easy to sew. If you have large bust and/or biceps, you may prefer to avoid stiffer fabrics, and make this shape mainly from knits of various weights.

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Raglan sleeves
Raglan sleeves have two separate stitching lines for each sleeve. And no shoulder seam – the sleeve fabric piece goes up over the shoulder and ends at the neckline.
The easiest have completely straight sewing lines.
straight line raglan sew diff raglan
left – my diagram, right – Sew Different pattern

Or the seams are slightly curved, with armhole and sleeve edge curves the same shape.
magic raglan
Burda discontinued pattern

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Square underarm
These look easy – just straight lines, but actually need another skill to get a non lumpy result.
Add the skill of stopping the stitching at a specific point.
square armhole

The key to avoiding underarm fabric scrunching on these armholes is not to stitch into the seam allowances. Then the seam allowances can move freely to where they need to be, rather than being held by the stitching in a place which pulls on the fabric around the stitching.

A square set sleeve looks simple as there are no curves. But to do it well needs the ability to stop sewing at a specific point, so you don’t stitch into the seam allowances where the seams join.

See diagrams below for sewing a flat set sleeve, as the method is similar.
Mark the underarm points on the sleeves where the seam stitching lines cross.
Stitch the armhole seam only between those points.
Then stitch the side and sleeve seams separately, also only up to that point.

Basic sewing machines usually can’t sew one stitch at a time under the control of the foot pedal. If so, stitch close to the end point. Then make the last few stitches to the stopping point by ‘walking’ the stitching – stitch manually by turning the hand wheel (turn the top of the wheel towards you).

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Cut-on sleeves
Add the skill of sewing strong sharply curved seams where the fabric lays flat when opened out to the right side.
vogue 8605
Vogue 8605

No clear dividing line between these and the dolman/ batwing sleeve. But here the underarm seam is sharply curved, so needs special technique. Both front and back patterns are the same shape.
The problem is the stitching line is longer than the cut edge, which stays taut when the garment is turned out to the right side.
So much clipping is needed at the curved underarm to get the fabric to lay flat. Double stitch round the curve for extra strength, and the results are stronger if you can clip on the bias, not at right angles to the seam stitching. See the sections on inward curves in this post from Sew4Home.

But that does leave little bits of seam allowance which wave around and look awful after the garment is washed. You can get a better result if you have a serger/overlocker, as they can produce viable stitches without fabric. This can keep the seam-allowances held together.
e-s harper
Elizabeth Suzann Harper
Spread out the seam allowances while overlocking, so the edge has a curve in the opposite direction.

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Sleeve sewn ‘flat’ / ‘laid on’
Two special skills here :
– sewing 2 different curves together.
– avoiding lumpy distortion at the point where the 4 seams meet – see also above on square armholes.

Sleeves which can be sewn on ‘flat’ have a flatter wider sleeve cap and a deep (shoulder point to underarm) armhole. Usually in casual and shirt styles.
flatset sleeve
from Cutting Lines post, link below : armhole above, sleeve cap below
I added the arrows.

It’s the stitching lines that need to match, not the fabric edges. The stitching lines should be the same length, while the sleeve cap edge is longer and the armhole edge is shorter.

The point where armhole and side seam stitching lines cross is marked on this photo by blue dots.
To find the crossing points on your pattern, mark the stitching lines at these corners. When sewing, match the dots for the sleeve to the armhole dots.

Pinning sleeves to a garment, photo tutorial from Cutting Line Designs.

While stitching two different curves together, keep checking that the under layer of fabric is flat and undistorted, as well as the upper layer, so nothing that isn’t supposed to be is getting caught in the stitching. Though if it is, as nothing has been cut, you can just unpick and stitch again.

Avoid lumpy distortion at the underarm, two methods :

Here’s a photo tutorial from Blueprints for Sewing about sewing the seams.
Basically, in this method, you’re sewing the underarm in the same way as for an armhole sewn in the round.

Another solution is to avoid stitching across the seam allowances when stitching the ends of the seams at the underarm (see above on square underarm).
See the dark blue dots on the photo. They mark where the 4 seam stitching lines cross at the underarm (there are also dots marking the centre of the sleeve cap). The 4 seam ends which meet at the underarm are : both ends of the armhole seam, and the inner ends of the side and sleeve seams.
The stitching is done in 2 or 3 steps :
First step – stitch the armhole seam joining sleeve to body, between the dots, backstitching at ends.
flat armhole seam
The body side seam and sleeve underarm seam can be stitched in two ways :
One step – stitch seams in one continuous line, pivoting if necessary at the underarm.
contin underarm
Two steps – the best result is obtained by stitching side seam and sleeve seam separately, so all seams are sewn only as far as the dot. Make sure the seam allowances are not caught in any of the stitching, that there is no stitching in any of the seam allowances, so all the fabrics can move freely as needed.
to dot only
Images from oop Simplicity 8856

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Fitted armhole, sleeve sewn ‘in the round’
Add the skill of sewing in the round.
And perhaps dealing with one stitching line longer and ‘eased’ to match the other.
Usually the most challenging method of attaching a sleeve. But patterns assembled this way can achieve the closest fit.

Around the underarm curves the cutting lines and stitching lines on both bodice and sleeve are usually the same length and curve.
Over the sleeve cap the fabric pieces have different curves, so the cutting lines and stitching lines are different lengths.
In some patterns the stitching lines on sleeve and bodice are the same length.
In other patterns the stitching line on the sleeve cap is longer than the stitching line of the armscye, there’s some ‘ease’ which needs extra handling.

‘Easy’ patterns (and cheap modern manufacturing) have front and back armholes the same shape, so the sleeve can be cut on a fold, as in this example.
Kwik Sew patt pieces
pattern for knits from Easy Sewing the Kwik Sew Way book

But on most human bodies the front and back armholes are not the same shape, so using a complete sleeve pattern can give a better fitting result. Especially in woven fabrics.

Fitting :
With this sort of armhole, it can matter whether it fits well.
Sew Sew Live has an extensive tutorial (not free). You get two downloads :
– a .doc with links to two videos, one on fitting one on sewing (if you have a Mac the .doc will open in .pages).
– a .pdf with summary notes on fitting, and pattern pieces for practicising sewing in a sleeve.

If you look carefully at the time line of the 1hr.50min. fitting video, you can see it’s in sections. Hover your cursor over a section, and what it covers appears above the time line. Though I suggest watching the whole thing first, to get oriented to the issues.

I find it essential to pin carefully, even to baste the armhole stitching.

Sewing in the sleeve : Strong differences of opinion here. Some people like to sew in a sleeve with the sleeve cap down, next to the feed dogs. I like to sew with the sleeve up.
These videos, and the SewSewLive one above, all have the sleeve up :
A general video from Sure Fit Designs showing both fitting the sleeve into the armhole and stitching.
Another video with all the steps from Sew Over It patterns.
This video just shows the sewing, from Londa Rohlfling.
Notice although this armhole is sewn ‘in the round’, it is not around the machine free arm. The stitching is done from inside the ’round’.

Definitely a technique where it’s worth making some samples until you feel confident.

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Links available February 2021

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