How to Draft a Trousers Pattern - A Tutorial

Hello my dear readers,
This month I have really had trousers on my mind. A trip to Banana Republic where everything was lovely, expensive, and way too short for my long legs had me thinking, "I can make this! Why would I pay $100 for something that just won't quite fit right?"

I always do this. I call it the seamless loop. I want a garment, but it's expensive and I could make it if only I could make the time, which gets me thinking about how much my time is worth, how busy I am, and that I technically make enough money to treat myself to a lovely thing like that once in a blue moon. But I just can't justify buying it, knowing that I could make a better-fitting one... and it all goes through my mind for long enough that I get sick of it all and before I know it, I'm cranky, frustrated, and without either a purchased or handmade version of what I wanted in the first place. Have you ever done this? It sucks!
So I decided to break the cycle. I am drafting a few patterns to test out the fit, length, waist rise etc. until I have the perfect pair. 

I also decided that I would create a tutorial here in case any of you might like to try trouser drafting for yourselves!
Here's what you'll need:

Paper, long enough for your high waist to floor measurement plus a few inches more, and wide enough for 1/2 your hip measurement plus a few more inches. (a nice, 36" wide roll does nicely!)
Pencil,
Eraser,
Rulers, including yardstick or a tailors' square if you can get one.
A French curve, hip curve or other curve drafting tool.

And of course, you'll need your measurements! This tutorial is adapted from a 1940's/ 1950's trouser so you'll want to pay attention to your vintage sizing.

And now for how it's done!

I. - See illustration above.

A to B - Equals side length measurement.
A to C - Equals 6 3/4” for size 12
              6 7/8” for size 14
              7” for size 16 and up...

C to D - Equals 1/4 of hip measurement plus 3/4” for ease. Square this line across at C.
C to E - Same length as C to D. Extend line D-C to E; then pivoting at D, draw an arc line above E.
A to F - Equals crotch depth measurement plus 1” for ease. Mark point F on line A-B.
G to H - Equals hip line D-E. Draw this line through F, parallel to hip line D-E.
G to I - Square this line up at G through D, making this line 1/2” less than A to F.
H to J - Equals 1/2 of line F to H. Extend line G-H to J.
H to K - Equals 1/2 of line H to J.
K to L - Equals line G-I (center front) plus 2” for center back line. Draw this line from K to L, touching the outer most curve of arc line.
G to M - Equals length from K to J.
G to N - Equals 1 1/2”. Draw a diagonal line; then draw a curved line from D to M through N.
K to O - Equals 1 1/4”. Draw a curved line through O.
G to P - Equals length of F to B. Square a line down at G.
K to Q - Equals length of F to B. Square a line down at K.
P to Q - Connect for lower edge.
P to R - Equals 1/2 of line P to D.
R to S - Square a line across at R for knee line; then draw slightly curved lines from M to R and J to S for inner leg seam.
B to T - Equals 1”.
T to C - Connect.

II. - See illustration above.
Draw waistline slightly curved, from I to A to L. Reduce waistline to fit 1/2 of waist measure. First make part of reduction at sides and center front. Then make a dart in back and a pleat in front at follows:
C to U - Equals 1/2 of C to E.
L to V - Equals 1/2 of back waistline; then draw a V-shaped dart, 6” long.
D to W - Equals 1/2 of D to C.

III. - See illustration above.
For crease lines on front and back, divide the knee and lower lines in half; then draw crease lines from bottom to hip line. For waistband, make a double band 1 1/2” wide, finished and the length of the waist measure plus 3/4” extension for left side opening. To complete pattern, add seam allowances to all pattern pieces and hem allowance to trouser bottoms. Make corresponding notches.

And there you have it! The straight waistband should only be used if you draft your pattern at waist level. If you lower it closer to your hip line, you'll need to draft a curved waistband.

Aaaaand on a completely separate note, I have decided to have a sale this week at Mrs. Depew Vintage! If there is a pattern you've been eying, now is the time to try it. Use coupon code "FLUFFEHKITTEH " in the box at checkout for a 15% discount - good until the 21st of October.

Happy sewing!