How to know if you need a Bust Adjustment
If you are larger than a D cup you may want to perform the Full Bust Adjustment, though we have provided a good amount of ease in Hawthorn. The FBA adds extra ease in the bust, which prevents the fabric from stretching horizontally.
To determine how much fullness you need to add, cut your muslin in a cross shape right over your apex, and pin some fabric behind it. Measure to see how much length and width you need to add.
If you’re an A or B you will likely want to do the Small Bust Adjustment. If you make a muslin first, you may notice an excess of fabric at the apex of the dart, as well as diagonal bunching between the side and bust seams.
To determine how much fullness you need to remove, pinch out a cross shape over you bust apex. Measure to see how much length and width you need to subtract.
If you’re not sure what you’re measurements are, or if you think an DD(E) sounds impossibly large, you may want to consult the Nordstrom Bra Fit Guide. Or better yet, go get fit! I received my fit certification working in their lingerie department and I can’t recommend it enough.
Step by step: FBA & SBA
The FBA and SBA follow the same steps right up until the end. So whichever you are doing, follow along.
1. Draw in your bust apex (the point on your bust that sticks out the most). To figure out where this is, mark the apex of your own bust on your muslin, then measure from the waist and side seam. Mark it in the same place on your pattern.
If you are doing a bust adjustment before making a muslin, a good rule of thumb is that the apex is about 1 inch from the tip of the dart.
2. Mark a bit of 5/8″ seam allowance at the curve of the arm hole.
3. Draw a slash line up the middle of the dart, up to the apex point (shown in blue).
4. Draw another slash line from the apex point to the seam allowance marker at armhole (shown in green).
5. Draw final slash line from the apex point straight out to side seam (shown in red), parallel to lengthen/shorten line.
6. Cut upward along slash line 1, pivot and continue cutting along slash line 2, stopping at seam allowance marker.
7. Snip into armhole seam allowance, up to your marker line but not through it. This will allow the pattern pieces to pivot.
8. Cut inward along slash line 3 up to the tip but not through it, again enabling the pattern pieces to pivot.
9. Cut all of the way through lengthen/shorten line on the right side of the dart.
Separating this chunk will allow you to lengthen or shorten the bodice, which you need to do in order to accommodate for the length change in the side seam that happens when you add/remove ease.
10. From here you will either swing the pieces out (as shown above) adding the amount of ease you determined you needed when making your muslin, or swing them in to remove fullness (as shown below).
Note: For the FBA, you’ll notice that swinging the pieces out lengthens the side seam. For a more fitted and tailored look, convert that extra length into a side bust dart! Tape a piece of paper under that gap in your pattern. Then simply draw the tip of the dart about 1 inch to the left of the apex. Draw the legs so that they cross the gap right at the seamline. Now you’ll be sewing an extra dart, and won’t have to worry about the length of the side seam changing!
11. Draw new dart legs, starting at original dart legs at seam allowance, up to your new dart tip (shown in black).
Note: Be sure to measure your new dart legs to ensure they’re the same length. If they’re not, you will want to lengthen or shorten the bottom right corner piece, altering the right dart leg to match the left.
12. If you are doing an SBA, you’ll notice that the side seam is now a little shorter. Shorten the bodice back piece by the same amount by folding the piece along the lengthen/shorten line.
If you’re doing the FBA but didn’t want to add a side bust dart, same thing. You will need to lengthen the bodice back by slashing along the lengthen/shorten line, so that the front and back will match up at the side seams.
And you’re done! Bonus Tip: If you’re altering a tissue pattern that you wish to fold up and store to use in the future, you may want to use medical tape for your pattern alterations. This allows you to gently iron the fold lines out because medical tape doesn’t melt like other tape.
Tune in tomorrow for a tutorial on how to split your bust dart into two darts! This is very useful for those of you with large busts, because it will give a softer, less pointy look to your bust.