[Edit 7/26/15: New photos!]
Here is another post about vests. I do hope you aren’t tired of seeing posts about vests. The silver one has a higher neckline than the previous ones, but is constructed in pretty much the same way. The white one is a bit different from previous entries, as it’s a bit of a different style. It is double-breasted and has a collar. I made them for my friend Orange (he did the buttons and buttonholes because my machine needs to be serviced).
The difference in the pattern compared to ones that aren’t double breasted is that there is a larger extension out from center front, away from the rest of the front, which creates a greater overlap. Instead of a basically V-shaped neckline, the neckline goes all the way to the wearer’s neck and a collar is sewn then inserted between the body and the facing. Unfortunately, I neglected to take step-by-step photos of the sewing process of this vest and the silver one. (But do see my vest entries, part one, part two, part three, as the majority of sewing is the same.)
The collar of this vest will stand up when the vest is buttoned all the way. You will want to make a mock up/fitting muslin, of course, so you can fit the vest to the wearer. The collar is a wide (2 or 3 inches) rectangle that is very slightly curved from about the shoulder seam to the center front and is one piece. You might need to experiment and see if you’ll have to make it out of 3 pieces (back and each front) because you might need some curving in at the sides.
When you have gotten to the point where you’ll sew on the facing is the time to add the collar. It gets sandwiched between the facing and the fronts (but just sewn to the back, not the back lining, which will cover the seam up later). The collar and under collar both need to be interfaced. So you’ll want to make sure the collar piece(s) and under collar piece(s) are sewn together first (any seams of collar and under collar, then collar to under collar, then clip corners and curves, understitch the long upper edge that is away from the neckline, and press the whole thing flat and right side out). Make sure you pin the collar to the neckline so that the understitched under collar side will end up being on the inside of the vest. Proceed with sewing the facing. When the back lining piece gets sewn in, the collar is sandwiched between it and the back piece. Proceed with the rest of the sewing, up to doing the buttons and buttonholes.
The buttonholes will be along the edge of the left front. You can add one at the top and one at the bottom of the right front if the underlap will sag and show. The buttons on the right front will correspond to the buttonholes on the left, and the ones for the underlap, and also sew non-functional buttons on the left front, as shown in the photos.