I tend to wear quite relaxed and over-sized silhouettes, so I love to include a dropped shoulder in pretty much everything I make.
A dropped shoulder is when the shoulder point (and therefore the sleeve cap) of the garment lies beyond the natural shoulder point. The curve of the shoulder is distributed between the bodice and the sleeve (rather than all in the sleeve cap as it is in a set-in sleeve).
Dropped shoulders can be somewhat fitted, but are often used in more relaxed designs. The distance beyond the shoulder can just be a few centimetres, or a whole lot more.
To create a dropped shoulder the cap height of the sleeve is reduced and this distance is added to the shoulder line on the bodice itself. The sleeve cap tends to become flatter and wider in shape compared to the standard set-in sleeve.
As shown in the example, the more the cap height is reduced, the flatter both the sleeve cap and the armhole become.
To begin you will need to trace a copy of your standard sleeve block (or any other sleeve you would like to transform into a dropped shoulder style). Ensure you transfer all your markings, including the grainline, notches, as well as the bicep line.
Decide how far you would like the new shoulder to extend beyond the shoulder point. Mark a point this far down from the top of the sleeve on the grainline. This will reduce the height of the sleeve cap.
Reducing the cap height on the sleeve and adding it to the bodice will make the armhole smaller. To prevent the armhole from becoming too tight, it is often necessary to add width to the sleeve.
Do this by adding width to the bicep line.
I tend to add half the amount that I lowered the sleeve cap by to either side of the bicep line.
For example, when making the pattern for this shirt I lowered the cap height by 3cm, so I added 1.5cm to either side of the bicep line. This figure may change later when you check that the sleeve fits the armhole, but is a good way to get started.
Redraw the sleeve cap, starting at one end of the bicep line, passing through the notch, through the new cap peak point, and back down the other side, to the other point on the bicep line, via the notch.
Keep the line as smooth and even as possible - coming to a straight line at the peak of the cap. This ensures the sleeve will fit nicely into the armhole when it is sewn.
Redraw your side seams by drawing a straight line from each new point on the bicep line, down to meet with the original seam line at the wrist.
Next, you will need to cut along the new cap line you have just drawn, to remove the original sleeve cap. Cut very carefully and do not discard the piece you remove as it will be added to the armhole.
Cut the piece you have just removed in half, along the grainline, and label each side - front or back so you don't get them mixed up.
Take the front and back pieces of the pattern you are altering and match the front sleeve cap with the front armhole and the back sleeve cap with the back armhole.
Place the sleeve cap on the armhole, matching the pieces at both the shoulder seam and the armhole notch.
As you can see in the example, the cap piece does match the armhole at the shoulder but not at the notch, which is incorrect.
Make sure the piece matches at both points, as in the example above. Once satisfied with the placement, secure in place with masking tape.
Repeat previous step for back armhole.
Just how we widened the sleeve at the bicep line to prevent the armhole becoming too tight, we also need to widen the armhole. To do this, lower the underarm point at the side seam. I tend to lower it by 0.5cm - 1cm less than how much I took from the cap.
In the example I have been using, I had reduced my cap by 3cm, so I lowered the armhole by 2.5cm.
Repeat for back armhole - ensuring you mark a point the same distance down the side seam as you did for the front so that the side seams still match correctly.
Redraw the armhole with a smooth curve, starting at the shoulder point, passing through the notch and finishing at the new underarm point.
Repeat to draw back armhole.
Once the new armholes are finalised, move your attention to the shoulder seams.
There are two options at this stage. For a more fitted style, redraw the shoulder seam as a curve running from neck to armhole.
For a more relaxed style or fit the shoulder seam can be drawn as a straight line. Draw a line, extending from the neckline and across the shoulder, that meets with the armhole curve.
Repeat for the back, making sure that the shoulder line is the same shape and length as the front (this is when using slightly transparent paper really comes in handy).
Trace off your new patterns.
Now to check that the sleeve fits into the armhole, and to finish, check that all your patterns fit together accurately and add seam allowance.