Here are the last of the inner structure pattern pieces you'll need to create. Again, these aren't super difficult, but I took a lot of photos for you guys - I'm a very visual learner and figured maybe some of you are too. So while this post will look long, most of it is pictures.
The pieces we'll be cutting from muslin are:
1. Back stay
2. Side back stay for princess-seamed styles
3. Side front stay for princess-seamed styles
4. Carrier strips for machine tailoring
Back Stay and Side Back Stay
The back stay helps keep the back from stretching with wear, and keeps the fall of the fabric from the shoulders nice and smooth.
My pattern has a center back seam, so for my back stay I keep the center back seam allowance. If your back is cut on the fold, you will do this the same way, but from the fold line.
My pattern also has back princess seams, so I needed to make these two pieces together to blend the curve. If your back is one piece, you only have to make one back stay piece. Here is what the two pieces of my back look like together:
Starting from the back piece, mark a point 8 - 10" down from the neck, whatever you think will be comfortable for you. I'm short and I also have prominent shoulder blades and a low round back, so I marked my pattern 8" down.
Now move over to your side back piece, if you have one. Mark a point 3" down from the armhole on the side seam.
Place the two pieces together, overlapping at the seam line as in the first photo. Then draw a gentle S-curve to connect those points. At the center back, make sure that the first inch or so is perpendicular to the center back, i.e. don't start curving right away. Here is how these two pieces will look:
Mark them both with the same grain line as the pattern pieces.
Side Front Stay
Now, my tailoring book says to make this piece out of hair canvas, but I felt like I didn't want to have stiff canvas at the side of my bust and under my arm, and I didn't have to because my front is princess-seamed. I chose to make this piece out of muslin for a little more softness.
The theory for this piece is the same as for the two pieces above: the end point is that 3" mark below the armhole at the side seam, and the curve blends over to the canvas piece cut from the front. If your front piece doesn't have princess seams, you will have already done this and won't need to make this piece.
Here's how mine looks - note that my pieces do not form an uninterrupted curve like the ones on my back pieces. I haven't found it to be a problem. I made these pieces so long ago, I'm not really sure what I was thinking at the time! I was following a book, a pattern and a Craftsy class when I made these pieces so I had a mash-up of instructions.
I mentioned in the last post that the edge of my hair canvas piece should be narrower at that princess seam side. You can see in the photo above that in order to draw a curve from the apex over to the side seam 3" mark, I would have to cut out a fairly good-sized wedge. I may do that in the future, but this has worked fine for me so far. Take home message: don't get too hung up about these pieces being "perfect." None of them will ever show, and they are just intended to give the jacket a bit more structure and stability in high-wear areas.
Mark grain lines on this piece to match the side front piece.
The last piece you'll be cutting from muslin is a strip that goes all around the front edge, neck edge, shoulder and side. The canvas will be attached to this carrier strip and then trimmed away outside of the seam line, so that only the muslin is caught in the seam, reducing bulk.
To make this piece, start from the pattern piece you made for the front interfacing. Draw another line 1.5" from the edges mentioned above. Here's how this piece will look, shown on top of the front interfacing piece:
Note that my piece is based on a princess-seamed style. I included the armhole in my carrier strip piece so that I wouldn't have a tiny patter piece for that bit at the princess seam. When I assembled my jacket, I cut away the excess later - I found it much easier to do this way. If you're using a pattern that does not have princess seams, you don't have to trace the armhole - just make another carrier strip piece for the underarm section of your hair canvas.
Make sure to mark the grain line of this piece to match the grain line of the canvas and front piece.
Finally, here's a photo of the inside of the last jacket I made (machine tailored) where you can see a lot of these pieces: the back stays, canvas interfacing and carrier strips. This should give you an idea of how it's all going to go together.
Sleeve Heads - optional
Those are all the pieces we'll need from muslin. There's one extra pattern piece you may want to make at this point: you can make your own sleeve heads to match your sleeve piece. If you want to do this, simply trace a 2" wide strip to match the cap of your sleeve. Extend your piece a couple of inches beyond the dots. I've cut mine back after using it a few times because a couple of inches was too long for me, but you should start with longer piece until you know what works for you.
Make sure you mark which is front and which is back on this piece! It's easy to get it reversed! If you're going to use a sleeve head like this instead of the purchased rectangular ones (or even a home-made rectangular one) you'll be cutting this piece out of a thinner piece of microfleece or cotton quilt batting. I've used these a few times and honestly don't find there to be much of a difference between this shape and the rectangular one.
Those are all the extra pattern pieces you'll need to make - IF your pattern includes separate pieces for the lining. If it doesn't, let me know and I can show you guys how to make those if you like. If so, I won't be doing that until later - I never cut my lining until I get to the point where I need it because I don't like having all those shifty pieces laying around.
We're getting close to touching fabric!! Of course the next thing you need to do once you've made these pieces is to prep your fabric in whatever way is suitable. I'm using a cotton twill for my jacket, so I've washed and dried it. I'm hoping to start cutting out my pieces tomorrow. Exciting!