A Classic Navy Blazer: The Muslin

You may remember that I put a "Classic Blazer" as #1 on my list of fall/winter sewing plans inspired by Kate Middleton. I decided I need to jump into it before I lose my nerve, so this is the very first post in what may end up being a long-ish series as I muddle through tailoring for the first time. If you aren't interested in watching a novice make a blazer, avert your eyes!

You may also remember that I had picked Simplicity 1421 as my blazer pattern. Again, here's my inspiration blazer and my pattern:

Kate Attends SportsAid Line Drawing

However, I've already changed my mind! Simplicity 1421 is an unlined blazer with a construction method that relies on bias binding (i mean the tipping) to enclose exterior seams. This is pretty different from what I have in my tailoring books (well, the library's tailoring books), and I'm going to need all the guidance I can get, so I picked up a copy of Simplicity 2446 in the $1 pattern sale. It is a more traditional style and looks more like the example garments in my books. I didn't pick it the first time because I thought the lapels were a little too wide and the buttons were too high.


These patterns are pretty similar, but in addition to the lining & construction, there are a few differences between the two: 1421 has a center back seam which 2446 lacks, and 2446 has shoulder princess seams instead of 1421's armscye princess seams. I hate all these pockets so I wont be adding any, but 1421 has patch pockets, and 2446 has in-seam pockets (that seem pointless) with added flaps (that look stupid).

Additionally, the sizing seems to be pretty different between the two. For the record, I should be a size 10/12 according to my body measurements. In my muslin of 1421 (yes, I muslined that as well) I made a size 10 A based on a finished garment bust measurement of 35 1/2". I actually really liked the fit on that muslin, so I thought I would try for a similar size on the 2446. Looking for a bust of 35 1/2", I decided to cut out a size 6 B. A six! Now that I have my muslin all made up, I'm not sure if I'd like to size up and make an 8 (A, probably), but I do want this blazer to be fairly slim-fitting.

Oh, you want some pictures? Here you go:

DSC01353 DSC01358

DSC01355 DSC01357

This is the pattern with no alterations at all in the front or sleeve, which I think is a pretty good start! I took in the back a lot (it was practically straight down originally) but I think I'll let it out a little bit so it is a little less dramatically curved.What do you think about the fit? Should I size up one for ease's sake? And secondly, do you think the lapels are too wide? I was thinking of shearing them back about 1/2", tapering to nothing at the buttonhole, but I can't tell if I've just been looking at them for too long. I should also mention that I forgot my little shoulder pads for these pictures. Oops! 


ps: as far as i can tell, you can just move buttons wherever you want to as long as you adjust the lapel roll line. can anyone confirm this?

allie J.


  1. wow! you have been busy. Should you perhaps be fitting over what you plan to wear under this blazer? If you are ever planning to wear a sweater then keep that in mind. I think you could shave down the lapel if you want but I like it as is. Are the sleeves long enough? Perhaps try on a long sleeve shirt you might wear with it. I have never sewn a fitted blazer I am just thinking on your behalf. It looks Wonderful!!!

    1. The trick is that it's impossible to get a cotton muslin over a cotton sweater or shirt when the finished thing will have a slippery lining! I think I will be lengthening the sleeves, maybe a whole inch!

  2. The fit looks wonderful but in my experience that means it will feel too tight, how is it when you move both arms forward across the back. You definitely need to fit it over the weight especially if you will be wearing sleeves. Amazing fit patterns give you 1inch seams so that you can make the fit changes. The lapel looks fine,but I see what you mean a little narrower might be even better. It's going to be gorgeous!

    1. It's super hard to get the muslin on over things (anything!) since the cotton just wants to stick together--for the fashion fabric (wool) I think I'm going to baste and slip in the lining and see how it fits before I sew it all up properly.

  3. The fit looks great, I think you could narrow the lapel a little bit if you want but it does look nice as it is. I look forward to seeing the finished result!

    1. Thank you! I think I will trim the lapel by about 3/8". Any more and I would have to modify the collar too...

  4. I think a narrower lapel would make it feel fresher and less 1990s corporate.

  5. Have you finished this yet?! I'm looking at making the same pattern and would like to see what yours looks like finished. How did it make up in the wool? Thanks :) x



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