Splitting the Shoulder Dart
Helen Joseph-Armstrong assures me that the shoulder dart can be relocated in one of the same manners as the bust dart, through slash and spread or pivoting the pattern piece. But, there are three usual ways to relocate a shoulder dart.
First, an observation. I don’t usually see shoulder darts in the big 4. This is not to say they don’t use them, I’m sure they have. Just not in the patterns I usually pick. And why are there shoulder darts. The bust dart seems fairly self explanatory, being used to pull excess fabric in around the convex shape of the bust. Well no matter how good your posture is, the shoulder muscles ALSO tend to be a bit convex, hence the shoulder dart.
Now, to moving it. The first most common move is a slash and spread, but in this example, you are relocating the dart to two locations.
Basically, extend the shoulder dart to your horizontal balance line (HBL) that runs from center back to armscye. Pick a point in the neckline and extend a line from the neckline to where the dart meets the HBL. Cut out the dart, then slash the neck line and HBL from armscye to but not through where the dart point meets the HBL. Close the shoulder dart and the dart excess will be transferred equally to the armscye and neckline.
You will have to either recut the neckfacing or ease the new neckline to meet the facing. The sleeve should handle the adjusted ease fine, but as always when making pattern adjustments, make a mock up to ensure proper fit with the adjustments and make sure the fit is comfortable. And there is the first method of moving the shoulder dart.