Inserting sleeves often needs sewing together different shape curves, so this can throw some people.
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.

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. 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
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.

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
right – Sew Different pattern, left – my diagram

Or the seams are slightly curved, with armhole and sleeve edge curves the same shape.
magic raglan
Burda 117

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. (photos on the way)

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.

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).

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.
Much clipping needed at the curved underarm to get the fabric to lay flat. So 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.

Sleeve sewn ‘flat’ / ‘laid on’
Add the skill of sewing 2 different curves together.

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, armhole above, sleeve cap below
I added the arrows.

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.

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 all the seam stitching lines cross at the underarm (there are also dots marking the centre of the sleeve cap). When sewing armhole, side, and sleeve seams, don’t stitch into any of the seam allowances beyond that point.

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.

Often around the underarm curves the cutting lines and stitching lines on both bodice and sleeve are 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 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 the sleeve into the armhole : It often helps to start by sewing a gathering stitch around the sleeve cap, to control the ease.
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 all have the sleeve up :
Here’s 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.
And another video just showing the sewing, from Londa Rohlfling.
Note 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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