How To: Draft a missing pattern piece

A couple of weeks ago, a reader asked how I’d drafted the missing pieces for Vogue 9996 (1960) as mentioned in a previous post (actually, that post is Part 3 of 3). Rather than answer in the comments, I thought it would be easier to write a new post, and then I immediately put it off. What better time than a gorgeous, warm, sunny Saturday (when I should be sewing or packing for my upcoming trip) to hang out in my basement office and finally get around to writing said post?

First off, this “how to” is along the lines of Do As I Say, and Not As I Do. What I say is: this method has a certain level of inaccuracy. If you’re a Seamstress, just stop reading right now. You will possibly break out in hives and/or start crying. Besides, you already know how to draft a pattern. If, however, you are “merely” Someone Who Sews, and have a scanner and printer, and are caught in a bind with a half-finished garment, and are okay with taking shortcuts marked with signs such as BRIDGE OUT, and are maybe using a forgiving fabric, AND don’t need the finished item to fit like a tailor-made glove, then read on.

NOTE: If you’re missing nothing but a facing piece, stop right here. You can recreate the facing simply by tracing the piece it is the facing for, but make it only about 2″ deep. Now carry on with your sewing. If you don’t understand what this means, skip ahead to the TEST below.

Okay, here’s the quick-and-dirty trick for quickly recreating a missing pattern piece using very little math and no actual drafting: There should be an index of the included pattern pieces, printed on your instruction sheet(s). It looks something like this:

That there index is typically drawn to scale. Which means that you can measure a full-size pattern piece that you do have against its representation in the index and find out how much that drawing has been scaled down. (If you don’t have an index, you can do this same trick with the cutting layout. If you don’t have a cutting layout either, you should really consider using a different pattern.) Using the above as an example, let’s say you have everything but piece #2, the bodice back.

TEST: if you couldn’t tell that piece #2 is the Bodice Back from looking at the above index, this entire technique may be a bit overwhelming for you. Stop here and sew a couple of garments from complete patterns to get some practice in before you start taking confusing shortcuts like this.

Okay, so let’s take a pattern piece for the skirt, and measure the longest edge. Let’s pretend it’s 30 inches long (I’m not measuring the actual pattern pieces in this example, so don’t think you can cheat and make this particular dress from using these instructions). On the index, that corresponding edge is 1.625″ long. You wind up with an equasion that looks like:

1.625 * X = 30

…wherein X is your mystery number. Insert some 8th grade algebra here to deduce that you need to multiply the index drawing by 18.5 to make it life-size (If 1.625 * X = 30, divide both sides by 1.625 to solve for X). If you double-check the math, you’ll discover that 1.625 * 18.5 is actually 30.0625 but I warned you that this method was a teensy bit inaccurate. Besides, you’ll likely err that small of a difference when you cut out the fabric.

Okay, now let’s measure piece #2 on the index. The waist length on the index drawing is exactly .5″ long. Multiply by 18.5 to determine that it should be 9.25″ long. Scan in your missing piece from the index, adjust it in the computer program of your choice until it’s “life size” based on your math, and print it out full size. After a bit of taping if you had to tile it together, you have your missing pattern piece! It will be missing helpful marks such as grain line and darts, but you’re an advanced enough sewer to be able to figure out those bits. You should test out your new piece by pinning all of the pattern pieces together before you cut any fabric. If the piece you made seems way off, either your math is bad or the index for your pattern isn’t drawn to scale. Try again with the cutting guide instead of the index. If it’s still way off, well, at least this method wasn’t a huge investment of your time. Try scouring PatternRescue for your missing piece.