Saturday, 20 April 2013

How to Draft A Custom-fit A-line Skirt Pattern

When I started to sew I wanted to be able to make my own designs. As I found out later, that means being able to draft sewing patterns. Skirts are easy to draft so this is good place for a beginner to start.

This will be a series of tutorials that will show you how to:-
  • Draft your skirt pattern
  • Cut your fabric
  • Sew the skirt
  • Sew a professional back centred-zip
  • Line the skirt
You will need a basic sewing machine (at least a straight stitch and a zigzag stitch) and a sewing kit. For the pattern drafting you will need:
  • A long, straight ruler or yard/metre stick
  • A square (a piece of card will do). Funnily enough, "set squares" are actually triangular rulers.
  • A French Curve or Hip Curve
    (Note: the above three items can be replace with a Shoben Fashion Curve or a Dressmaker's French Curve)
  • A calculator
  • Large sheets of paper (you can use newspaper or greaseproof paper)
  • Pens and pencils
I will be working in metric. You can work with imperial (inches) if you wish, but metric easier to use on a calculator. In case you are using imperial measurements, here are some decimals and their fractional equivalents:

1/2  =  0.5
1/4  =  0.25
1/8  =  0.125
1/16 = 0.0625
1/3  =  0.33333...
1/6  =  0.16666...7

The measurements you will need are:
  • Waist plus ease
  • Hips plus ease
  • Waist to hip length
  • Skirt length
  • Dart = ((Hips+ease)-(Waist+ease))/14
If you fill copy this in now, it will save mistakes later. I've put my measurements in for examples. It's quite wide, so you'll probably need to click on it or zoom in.



You will also need to work out your dart measurement. This is where a calculator is very handy. Here is the formula:

(Hips + Ease) - (Waist + Ease)
14

If you have some silly long decimal number (more than 1 number after the decimal point), you can round up or down to the nearest 0.5cm. This is your dart measurement.


We will draft the front and back pattern separately because it is quicker later.

We'll start with the front.

  • At the top of sheet of paper, about 10cm (4") down and 2cm (3/4") in, mark A. Square down the skirt length and mark D.
  • Square across your "Front Hips" measurement (the eighth column) and mark B.
  • Square down the skirt length and mark C. Square back to D.
  • Measure down from B your waist-hip side-back measurement and mark E. Square across to the A-D line and mark F.
  • Up from F, measure your front waist-hip measurement and mark I.
  • From A measure across on the A-B line 1/4 (waist + ease) + 1 dart width. For me, this is 15.25cm + 2cm = 17.25cm. Mark this point G.
  • Square up 1.2cm (1/2") from G and mark H. Connect I and H straight. Divide this line in three. Square down from the third-mark nearest H by about 1/2 of your waist-hip side/back measurement (here, 10cm).
  • On this line, make a dart. For me I measure out 1cm each side of the line giving a 2cm dart. Draw the dart. In the illustration I have curved this dart. It's best NOT to do this because you need the fabric to allow room for your tummy.
  • UPDATE: I'm not sure if I've included this step (I can't find it). Connect H to E, curving out 0.5cm at the mid-point to give tummy-room. Even if you don't have much of a tummy, this room is good for the high hip area (the pelvis). If you don't curve out, your skirt will ride up.
  • Now we will give the skirt a bit of flair. This gives an A-line, and saves your putting a vent in the back. From C on the D-C line, measure out 1/4 D-C. Mark X (I haven't). Measure E-C and make a line from E to X the length of E-C Mark X2. Connect X2 to C with a smooth curve, making X2 a right angle so that it will be a smooth line with the side seam on the back skirt.
  • Add seam allowances down the side seam. 1.5cm is usual, 1cm may be preferred if you are sure of the fit, or you can use 2-2.5cm seam allowances for your toile.
  • Add 3-5cm for a hem allowance along the bottom of the skirt. When you sew, you will have to ease the bottom edge in a bit because it is bigger than the inside of the skirt.
  • Cut a generous seam allowance along the waistline edge because we are going to blend the line and make sure that it is a smooth curve.
  • Cut out your pattern. Fold the dart. Draw the waistline as a smooth curve. Now unfold the dart and add 1-1.5cm seam allowance along the waistline seam. Draw a notch at point E on the side seam for the zip and for matching when sewing.

Now we'll do the back. It's a lot like the front, but with more ease and an extra dart.
  • Start at the right-hand edge of the paper this time, 10cm down and 3cm in. Mark A.
  • Draw across, the length of your "Back Hips" measurement and mark B.
  • Square down from A your side/back waist-hips measurement and mark C.
  • Square across from C, the length of AB. Mark D. Square up to B.
  • Down from B mark your side/back waist-hips measurement and mark E. Square across to the AC line and mark F.
  • On line AB measure from A your Quarter-waist + 2 darts measurement. Mark G.
  • Square up 1.2cm from G and mark H. Connect A-H straight.
  • Divide AH into three. Each of the marks along the line will be a dart so square down from each of them.
  • The one nearest the CB will be 3/4 your side/back waist-hips measurement.
  • The other one will be 2cm shorter and L.
  • Make each dart your dart width as you did for your front dart, and draw the dart shapes. I like mine to curve out from their centre-lines so that they fit the shape of the back better.
  • Connect H to E, curving out 0.5cm at the mid-point of the line. This adds ease for the tummy area. If you don't add this your skirt will ride up.
  • A-line the hem as for the front.
  • Add seam and hem allowances, and notches at the line E-F for matching and for zip placement. Leave a extra paper at the waistline because you have to fold out the paper darts and smooth out the waistline curve. Otherwise you may have a pointy waistline. (Same as for front.) Then add seam allowances, and mark the darts clearly as in the illustration or as you best see fit.
This is your basic A-line skirt pattern. If you have not made your own pattern (and even if you have, really) it is a good idea to make a toile out of light-coloured fabric. You must mark the vertical and horizontal grainlines so that you can see if the skirt is balanced when you wear it. Add or take fabric away where necessary to get it to balance. This can sometimes mean that you need a full pattern (i.e. not mirrored or "cut-two") if you are asymmetrical. But don't be too picky. It does no good to get paranoid about slight wrinkles and things on your clothes. No one but you (and other very picky seamstresses) will notice. : )


You may like to have a waistband for fitting. Just cut a rectangle of fabric to your waist measurement + 2.5cm (for overlap), and 5cm deep (it will be folded over). Then add seam allowances all the way around. It is a good idea to interface this even on your toile to eliminate non-fitting-related folds and wrinkles.

There shouldn't be much to change if the instructions were clear enough to you, and if your measurements and maths are correct. That's why it's such a good idea to work out your maths (carefully) first. And it saves a lot of paper. (Oh the rolls of grease-proof paper I have got through because of sloppy maths!)

Once you have got the hang of drafting and have your numbers handy, you can draft a skirt pattern very quickly. I drafted mine like this in about an hour.

Extremely Brief Sewing Instructions for Skirt Toile/Muslin
  1. Sew the darts.
  2. Sew the CB seam from the bottom and stop at the notch.
  3. Using a longer stitch (3-5mm), baste the rest of the way up (this is much easier by machine).
  4. Insert zip be centred or lapped method.
  5. Sew side seams.
  6. Make waist-band and attach to waist-line. Add a buttonhole to one end and a button to the underlap.
  7. Hem.
(I told you they were brief. Don't worry, more detailed explanations will follow in the styled skirt make up.)


Once you have made and fitted your toile and transferred any changes to your pattern, you can adapt it to almost any style you can imagine. But I'll end this post because it's getting a bit long and will take ages to load.

Sabrina

P.S. If you make your skirt to these instructions and blog about it, please send me a link or put one below because I'd love to see it! : )