As promised (although about a week later than I meant to have this up!), here is how I made the tux and tails alterations to the suit jacket for this year's
Joker Costume! I spent ages looking for either a pattern for the right kind of jacket, or an existing tutorial for how to alter a basic suit jacket or blazer pattern to make it, but found neither. I guess there isn't a huge call for a jacket with tails pattern for little boys. So while it might not be in high demand, I took photos along the way of what I did to change the pattern, and am offering my very first tutorial! If you're looking for a couture way to construct this, you may want to keep looking, but it works great for costumes.
I started with the
Little Gentleman Suit Jacket because it's the pattern I have, but I'm pretty sure you could use any suit jacket or blazer pattern of your choice as a base. First, I traced the shoulder and neck line of the jacket in my chosen size. This pattern has a split bottom of the back, so I stopped tracing the back seam line at the point where it would split and overlap. This is where I say "do as I say, not as I do" and tell you to extend this by about an inch, plus your seam allowance. My jacket came out just a little bit shorter than I would have preferred.
From here, use a straight edge to find this length on the other side of your pattern piece. I drew a very light pencil line, since we'll be using this line again. Trace the shortened length on the side seam side of your pattern. While you're here, measure the length of this line. We will need it for the front piece later.
Now use a ruler, and draw inward along the line you just made to make a seam allowance on both sides. I used 1/2", since that's the seam allowance included in my pattern.
Also using a ruler, find the midpoint along that line and mark it.
From that point, measure down the length you'd like your tails to be, keeping your ruler perpendicular to the line you started at. Keep in mind that you will lose about the width of your seam allowance at the tip, so if you have a very specific length you want remember to add that in. I used 18" for my tail length for a size 10 jacket. Draw a line to and/or otherwise mark the length of your tails.
Using a ruler/straight edge, draw a line from where your seam allowance line stops to the mark you made for your tail length. Do this on both sides of your pattern piece. You should end up with a back piece that looks about like this.
Now that the back piece is complete, you'll need to trace the front piece of your jacket. Using the side seam length from earlier, mark that length on the side seam of your front piece, and make a parallel mark on the opposite side to shorten the length of your front jacket piece. Connect them, and this is the new bottom edge of your front pattern piece.
This is a completely optional step, but one I did to reduce bulk in the front of the jacket. In a traditional suit jacket, the lining is split so that there is enough of a facing in the front made of the main fabric for the collar to fold over, but the rest of the side front is in a lining fabric. I used a curved drafting ruler, but you could wing it if you don't have one, or even use a straight line. Make a mark just before the midpoint of your shoulder, a couple of inches or so from the neck line. Also make a mark a couple of inches in from the front along the bottom. Using a ruler (curved or straight) draw a line to connect the two points.
Re-trace to create two pieces - a front lining and a front facing - remembering to add a seam allowance. Don't forget that seam allowance to BOTH pieces, or your front lining will be smaller than your outer front piece.
Cut the facing piece from your MAIN fabric, and the lining piece from your LINING fabric. Pin and sew along the line you created.
Open and press. Now use this piece as the lining in your pattern while you sew.
The other change I made to the construction of the jacket is where I turned it. Instead of leaving part of the bottom open, since I changed the bottom, I left a 4 inch gap in the back lining seam to turn. When sewing the lining into the outer jacket, pin carefully along the edges of the tails. Before turning, trim the tail points close to the seam, being careful not to clip your stitching. Turn your jacket right side out and stitch your opening closed - I hand sewed using a ladder stitch. Follow your pattern directions to finish. Congratulations, you now have a tux coat with tails!
