The Breakfast Club Wardrobe, Part 6: Modifying the Pants Pattern

The days grow fewer, but the work to be done on this project seems to grow and grow!

This past week I focused on modifying the pants pattern. Some of the grunt work I did sitting in the living room while watching the drama of the Tour de France unfold on TV.

Measurements

Thread Theory’s instructions for the Jedediah Pants pattern have the following (abridged) table for body measurements:

Feature 32 34 36
Waist 32″ 34″ 36″
Hip (Seat) 39″ 41″ 43″

My waist measures closer to 36, so that’s why I went with the 36 pattern for my first muslin.

On that muslin, I pinned out two inches of waistline and discovered it fits perfectly as a 34.  I measure 39″ at the hips, so my new plan is to start with the size 34 pattern at the waist, then grade to size 32 at the hips all the way down.

Based on my thigh and knee measurements, I could even consider grading down from 32 to 30 beneath the crotch area, but I want to see how this single change from 36 down to 34/32 works before doing more alterations.

Grading

Thread Theory has a tutorial for doing pattern grading of this sort on their blog. It looks straightforward, but there are some caveats to that method described in that article:

  1. The front pockets could gape a little too much
  2. The seat seam might not fit as well as it will the way the pattern was originally drafted
  3. The thigh area might become too baggy or too tight

I thought some of these problems could be overcome if you used the original pattern pieces as a guide to grade the curves, and also if you take the time to grade the smaller pattern pieces such as the facings and pockets so they also match the graded seamline for the larger pieces.

I can easily trim my 36 pattern pieces down to 34, then use them as a tracing guide against a new copy of the pattern, either traced or printed. Basically, I’m using Nancy Zieman’s pivot-and-slide method to trace an altered copy of the pattern.

Prepping the pattern pieces

I decided to print and tape myself a second copy of the pattern for a simple reason: the facing pieces are all printed in a staggered manner, so once you cut out a single size (say 36) you don’t have the complete set of outlines for a smaller size (say 34 or 32) any more. Here’s an example to illustrate what I mean:

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So by printing out the pattern a second time, I got a new set of facing pieces plus a second set of large pieces to trace the alterations onto. Please don’t tell the people at Thread Theory about this: they’re an environmentally conscious sort, being Canadian and all, and might be upset by my profligate use of paper and tape.

I started by trimming the new facing and pocketing pieces down as much as possible while still keeping both the 34 and 32 outlines. Here’s an example:

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I also trimmed the large pieces (front and back pant legs) down to 34 for both copies of the pattern.

Drawing the hip line

I wanted to grade from 34 at the waist to 32 at the hip. But the hip line isn’t marked on the pattern.

Following the instructions in Nancy Zieman’s Pattern Fitting with Confidence, I drew the hip line this way:

  1. Mark the crotch line.  This is found by taking the intersection of the crotch seam and the inseam, then drawing a line across the pattern. The stitching lines are used, rather than the cutting lines.  I added stitching lines by measuring 5/8″ in from the edge.
  2. Draw the hip line 2 inches above the crotch line.

Here’s the results on both the front and back pants pieces:

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Transferring the hip line to the facing pieces

To make sure the facing pieces match the pattern, they have to be graded the same way too: from the waist point down to the hip line. So the facing pieces need a hip line as well.

To do this, I matched the facing and pocket pieces against the front piece, then extended the hip line onto the facing pieces.

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Drawing the hip line onto the inside pocket facing

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Facing piece with hip and crotch lines added. (Only the hip line was necessary)

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Drawing the hip line onto the outside pocket facing. Here, I matched it up the facing as if it were assembled into a completed pants front

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Hip lines on the facings. As it turned out, I didn’t need to alter the zipper shield.

The back yoke is a special case, since it doesn’t extend down to the hip line; I’ll cover that in a moment.

Drawing alterations on the main pieces

Finally, it was time to alter the front and back pattern pieces.  Following Nancy Zieman’s pivot and slide technique, I stacked the two copies, then pivoted the 34 top piece until it matched up with the 32 line at the hip on the bottom piece. Then I traced the line to blend from 34 to 32.

I think to be true to the pivot and slide process, the pivot points should be at the intersections of the stitching lines. Otherwise, you’re altering the the seam allowances as well. But the amount of alteration here is pretty small so I don’t think it matters much here. I just used the corner of the pattern as the pivot point.  We’ll see how well this all works when I stitch it out.

Pants Front

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Grading center front from 34 at waist to 32 at hip.

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The result.

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Tracing line to grade front piece at side seam. (Oops, the camera auto-focused on my hand)

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Side seam after grading. From 34 at the waist to 32 at the hip.

Pants Back

Earlier I mentioned the back yoke piece is a special case. That’s because it must join with the pants back in order to get the full curve up to the waistline.  So I traced the stitching line on the yoke and back piece, and pinned them as if they were sewn together. Then I did pivot and trace to alter both pieces as one unit.

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Joining the yoke and back piece. The yoke has a curve, so here we join them at the side seam.  We will re-pin them when we alter the center seam.

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Both top and bottom must have joined yokes to pivot and trace.

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Finished result. (The center seam was altered off-camera).

Grading the facing pieces

The facing pieces are graded the same way as the pants fronts and backs.  Pivot from the corner to the 32-inch size at the hip line, and trace a new line.

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Graded pocket facing on bottom.

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Graded pocketing

For the facing and yoke piece, I cut the size 34 line at top, and the size 32 line at bottom.  I don’t know if that’s the correct thing to do; we’ll see how it sews up.

Finally, I didn’t alter the zipper shield, since the pattern piece is virtually identical between the two sizes.

Next Time

I’m about to go cut and sew a new muslin. I’ll show you how it looks.

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