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Small Bust Adjustment for Passionflower Lingerie Top

January 17, 2023 1 Comment on Small Bust Adjustment for Passionflower Lingerie Top

Our new 510 Passionflower Lingerie Top expands our size range to 4XL (58" bust). And since this pattern relies so much on the bust fit, we also offer each size with three cup options (B, C, and D). We want to help you with sewing fit, so this post will show how to measure to get your correct size and how to make a Small Bust Adjustment (SBA) in case you are an A cup (as I am).

To figure out which size, and cup size, is best for you, look at the size chart. The bust measurement is going to be the most important for this pattern, but you can also look at the finished measurements to make sure the empire waist (just below your bust, or mid-ribcage) will fit. I am on the larger end of a size Small, so I usually check finished measurements and cut a size Small. If I need to adjust to add a little bit at the hips, I will grade out to the next size up, but with this pattern there is so much ease in the hips (it's basically a circle skirt) that I don't need to worry about that.

To find your bust cup measurement, you need to take your high bust measurement and your full bust measurement. The difference between the two gives you your cup size. If there is a 2" difference, cut a B cup; if a 3" difference, cut a C cup; if a 4" difference, cut a D cup. So for instance, if your high bust measures 34" and your full bust measures 37", you will cut a Medium size from the C cup front piece (37-34 = 3" and 37" bust is our size Medium).

High bust measurement

Full bust measurement

The difference between my full bust and high bust measurement is 1", which is an A cup. So, for this pattern, the B cup will be a bit large and can have some bagginess that I might not like. So I am going to show you how to make a Small Bust Adjustment (SBA) for this bodice piece in case you need to make this adjustment also. I highly recommend making a muslin (or two or three) to make sure the fit is how you want it to be. Every body is different. Your bust apex may be different, or your shape may need other adjustments. A muslin will help you get a better fit even after this SBA.

Small Bust Adjustment for Passionflower Top

First, it helps to outline the darts in the size you are making with a colored pencil or marker. I used yellow below. Then draw a line through the center of the center dart, up through the dart point. I drew this is pink below.

The bust apex (largest point of the bust) is 1.5" above the center dart point. Draw a small circle there to mark the point. If you try this adjustment out and need to move the bust apex, this is where you want to start again.

Next, draw in the seam allowance at the top of the bodice piece. If you are making size XS, the seam allowance is already noted, but since I am adjust the size Small, I am marking 1/2" (13mm) from the cut line to show the seam allowance.

The bodice piece with seam allowance noted, darts outlined, and line through center dart (and apex) drawn).

Now, draw a line from the bust apex to the seam allowance. You are drawing a line to the approximate center between the side seam and the shoulder strap circles. This would be a point under the front part of the arm.

Next draw lines through the center of each of the other darts, but to about 1/4" to 1/2" of the bust apex. I drew them in pink below.

The difference between this cup size (B) and my cup size (A), is 1" (since B cup has a 2" differential between high bust and full bust measurement and A cup has 1" differential). So I need to take out 1" in the bust, which means I need to take 1/2" out of the bodice piece. And I need to spread the 1/2" between the three darts. So 1/2" divided by 3 is 0.1667 inches. At this point it is better to measure in mm, and 0.1.667" is about 4mm. So, starting with the center dart, mark a line approximately 4mm to the right of the center of the center dart line.

Then mark lines 4mm from the center lines of the other two darts. I marked these lines in pink below, then outlined them in blue.

Now cut up from the center of the center dart to the bust apex and then along the line to the seam allowance, clipping just into the seam allowance for a hinge.

Adjust the pattern piece so that the center of the center dart is moved over to the blue line. Tape the pattern piece in place here.

Now cut up the center of the other two darts to the bust apex, leaving a hinge at the apex. And adjust each of these two darts so that the center overlaps to meet the blue line. Tape in place.

Now, you almost have a new pattern piece! This won't lie perfectly flat, but you can give the pattern piece a little press to help it. Don't worry about the little bit of cupping - just flatten as best you can.

Next, I would trace a new pattern. I am using Swedish tracing paper below to trace the pattern with the new darts.

Your darts points aren't going to change much because we didn't take out a huge amount, but they lowered slightly. If you need to adjust your dart points after you make a muslin, you can adjust them from here.

Finally, you will need to put the original bodice piece back under your new one (I made two copies and kept one for this step). You can see the new bodice has a slightly different shape now and is smaller. However, since this bodice will be going onto a skirt and we haven't adjusted the skirt, we need to add back some of the depth we took out of the pattern piece so that it fits the skirt. Line up the center darts as best you can, and add onto the front and back edges the amount that is missing from those sides. You can see how I did this below.