January 18, 2012

1911 - transferring alterations to the pattern

Once you've sewn and fit a mock-up you've already used all of the skills needed to make the a finished corset, drafting, tracing, cutting, sewing, grommet setting, and fitting. For the rest of the sew along we'll just be building on and refining those skills. Yea.

So the fit works, now it's time to transfer the changes to the pattern. You will need paper, tape, pencil, a ruler, a tape measure, a hip curve, and scissors or a exacto knife.

First, if you added seam allowance to the top of the pattern when tracing and you want the additional height you must add that to the pattern. Everyone using the Corsets and Crinolines should keep that inch because we'll add to the top of the center back so we can use the 16 1/2 inch bones at at the center back. I'll explain this in more detail later, but for now start by taping the pattern to a piece of paper and draft the higher edge 1 inch from the pattern, the same way you added the seam allowance.

Use the hip curve to extend the seam lines so they reach the new top edge.

You should easily be able to see how much you altered each seam by measuring the fabric. There should be a line at the patterned seam 1 inch from the edge of the seam allowance, just measure the distance measure the distance to the alteration you sewed. Often when fitting the seams they may not have been altered the exact same amount. Say the first seam on the right side was taken in 1/4 inch, and the first seam on left side was take in 1/2. Split the difference. So the alteration will be 3/8. Remember that 3/8 taken in on a seam means that 3/8 must be taken off of each pattern piece that joins to make that seam. If you have been sewing for a while this is obvious, but if you are new to patterning and construction it isn't, and it's frustrating to sew up a corset and figure this out when it doesn't fit. So learn from my mistakes and make the change to both connecting pieces.

Go to the pattern and mark the alteration. For example, I let out the fabric 1/4 inch on the seam at the underbust line. So I'll measure 1/4 off the top edge of the pattern piece.

The new seam line is drafted so it blends to the waist using a hip curve.

Then I do the same thing to the other pattern piece. If you made large alterations you should measure and true your seams again, but for most any change won't be significant. You can see here the difference was just 1/8 of an inch. You can also see I scribbled out the old seam line so I don't accidentally measure or cut it.

If you need to reduce a seam mark the adjustment, draft the new line using the hip curve, and cut off the excess.

Whether adding to, or subtracting from, a seam your newly drafted lines should always blend smoothly into the existing seam line. If you are using the post Edwardian pattern you are done. Cut out your pieces and relax. Those of us using the Corsets and Crinolines pattern have one more step, adjusting the center back length, which I will explain tomorrow. Until then, take pride in your fabulous pattern drafting!


  1. Hi Jo. I'm a bit late to the fitting step and some things have come up. Firstly, the bones at the side seams kept popping off and I got frustrated trying to keep sticking them back on, so I gave up. Should I sew casings for those instead for the mock up? Also, my lacing strips are 17" long and boned, so when I sit down they jam into the chair and force the top of the corset up in the back. Should I be keeping track of how much extra lacing strip there is accounting for the difference in my final corset? Also, I have a V in the back and I'm wondering which seams I'm supposed to be adding to at the top and which seams I'm supposed to be taking from in the bottom? Should I just be trying to split the difference between all of them? I'm going to post some pictures on Flickr to show what's going on and maybe there will be some other suggestions too. Thanks.

    1. Don't worry if the tape didn't hold the boning in place, you can still fit without it. If you're feeling ambitious then you can add a quick casing, but you should be fine. Don't worry about calculating extra lacing, you need slack to lace in and adjust so excess is OK. I had the same problem with the boning in the center back of my mock-up. Hold it to your body so it bends with the curve as you sit. While sitting straight hold two or three fingers against the seat of the chair and mark above the top finger on the corset. If couldn't take a picture when I was fitting, but I can draw an illustration if it's still not clear. Let me know. The boning should end at that point. Is the mock-up loose at the bottom? If so just pinch the excess fabric where ever it happens to be. Then look at the top edge, is it cutting in anywhere? Often the back seam by the shoulder blade can be let out a bit and maybe at the side seam too. I'll look at the images you posted and see what everything looks like.

  2. Hi, and sorry for the delay in putting the pictures on Flickr. They are up now. The mock up is very loose at the bottom, yes.