Start with the shoulder seams sewn on both the lining and outer pieces:
Prepare the sleeves by gathering if needed, then pin or baste them right sides together with the outer layer, leaving about 1.5 inches free at both sides of the underarm portion of the sleeve:
Pin the lining piece on top, right sides together. Pin the arm seam, leaving 1.5 inches free at each side of the underarm, and pin around the neckline and back seam. It will look a little lumpy because the bulk of the sleeves inside, just be careful not to catch the sleeves in the neckline or back. Roll them up a little if needed.
Sew the arm seams, around the neckline, and down the back. For this dress, I only sewed 3/4 of the way down the back seam, but for a dress with a button placket down the whole bodice back, sew all the way down. Make sure you leave that 1.5 inches at each side of the underarm seams! =)
Clip, notch, trim, and grade your seams as needed, then reach through the shoulder of the front bodice, grab the back bodice piece, and pull it through. Partially through:
And all the way through:
Repeat for the other side of the back, and you should have something like this:
Press all of the seams you just sewed, then sew the sleeve into a tube, right sides together. I did a French seam for mine, but if you do a regular seam you'll want to finish the edges. Match outer to outer and lining to lining and sew all four side seams right sides together. You'll have something almost finished, with a hole at the underarm. Press all of the side and sleeve seams.
Fold the lining and outer up from that hole so they are right sides together, match the seams of lining, outer, and sleeve, and pin.
Sew the opening closed, beginning and ending where you've already stitched for the rest of the arm. Trim, clip, and grade as needed, then fold everything back down and press. You will have this on the outside... nice and smooth.
And the inside should look like this:
Then all you have to do is repeat for the other sleeve, and you can go on to sew the rest of the dress!
Let me know if anything is confusing and I'll try to clear it up. And if you sew up a dress using this method, I'd love to see it! =)
Thanks for stopping by!