See how I steered clear of punny titles? Blurry sewing room shots and the yokes on me. There, got that out of my system.
Most trouser patterns now come with a centre front fly opening. Maybe you want to change this to a side or back opening? Maybe you want to change the way the waist shaping is arranged, darts into a yoke or shaped band?
You can do this with just about any pattern. A typical trouser block or basic pattern has some shaping on the side seams, a single dart in each front, and two darts in each back. The front and back centre lines shape in to a greater or lesser extent, depending on style.
Sometimes the front dart has been incorporated wholly or partly in a pleat, as in the Vogue pattern I altered recently. This pattern already had a yoke of sorts – a shaped band in lieu of a waistband, set lower than the true waist. The pattern designer will have drafted the original shaped band like this:
Pin the darts closed, draw in the band where you want it. Cut along the band line, tidy up the curve, add seam allowances.
To judge by the number of questions from beginners on sewing forums, there’s confusion about darts. Darts start at the waist and end in a point at the widest part of your anatomy.
Darts and seam shaping are just simple maths. The difference between the hip measurement plus ease and the waist measurement plus ease is the amount to be reduced. Blocks and patterns work to a standard of measurements, and a standard position for the fractions of that reduction -shaped side seam, shaping back and front centre, two darts in the back and one in the front. Seven positions to share the reduction amount.
This assumes everyone to be the same form, but in practice you might need more or less of the reduction at each of these positions, and you might need to move the position of darts and even side seam to get the best fit and look. Side seams get drawn as a steady curve, even though the body underneath might have a lumpy wave shape, out at high hip, in a bit, then out again at the pelvic hip joint for instance. Smoothing out the shape is usually more flattering. Darts are drawn as a triangle for convenience, but can be shaped as a curve if this gives a better fit.
It’s better to fit a pattern with the full complement of seams and darts and transfer the new fitting lines to your pattern before changing the style to a yoke.
The basic arrangement of darts and side seam to reduce the fabric between the hips and the waist gives flexibility for fitting, yokes not so much. If you don’t need a front dart, or have to extend the side seam at the front waist because of a larger tum, this is better done on a toile before making design changes . Changes to the height of the front and back waist are also common. You’re aiming for a trouser waist which is parallel to the floor. First fitting might find it dipping at the front or climbing high in the back or vice versa.
Once the fit is sorted you can draw any shape yoke through the closed darts and smooth out the shape when you’ve separated the pieces. The yoke can leave the tail end of darts. These can be dealt with in various ways – kept as small darts, or pleats, eased in, measured and the extra fabric taken out at the seam. The key is to walk the pattern before adding seam allowances so you can iron out discrepancies.
If you want to move a fly front pattern opening to the side or the back you just need to identify the centre front in your pattern and knock off any fly extensions. With an invisible zipper you won’t need anything more than basic seam allowances. Add extra if you intend to do a lapped zipper.
For some styles you can omit the side seam and just have a shaped dart instead, taking in the space you can see between the front and back blocks in the first picture. I did this for some linen trousers, putting an Italian pocket in using the side seam dart. On the right of the photo you can see the point where the side seam would be, and above it the back leg of the ‘dart’.
Below, a quick make, trousers with the waist shaping created with elastic. To do this from a classic pattern, you ignore darts, and draw the side seam straight up from the hip. Check the waist measurement will go over your hips.
These gardening trousers have inseam side pockets and a pleated patch pocket on one side for my secateurs!