How to Correct a Mirrored Knit Shorts Pattern

Here’s a quick review of a new free pattern that was released today, the Tupelo knit shorts from SewLikeMyMom.  Like several other pdf kids’ knit pant/legging patterns, it has a mirrored front/back rise, with instructions to adjust the rise height by trimming off the waist at an angle (photo shown under Fair Use doctrine for the purpose of product review):

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I will show you  how to adjust this pattern (and others like it) for a better fit.  Because this is in stretch knit, you can get away with sewing this pattern “as is”, however it will cause great fabric strain at the center-back seam, due to the lack of length and coverage of the back rise.

  • Woven patterns that rely on excess fabric will provide coverage but not good fit.
  • Knit  patterns that rely on excess stretch will provide coverage but not good fit.

The pattern prints out on 2 sheets for the shorts body, and 1 sheet for the self-fabric waistband.  I will concentrate on the body only; the waistband adds height to the rise but I’m not discussing height measurements, only proportion and angle.

Print the pattern  twice and tape together at the fold (photo looks a bit wonky as the camera angle is off; this is a mirrored pattern):

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Before working on the rise problem, let’s take care of a few details. The pattern needs to be trued at the hem….before trimming the side-seam off, fold up at the leg hem:

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Then trim off the side:

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Unfold back down:

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Draw in trued hem (repeat for left side of pattern):

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Next true the top of the inseam so that you won’t end up with a point into the crotch when stitching the inseams together front-to-back:

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Square off a 90-degree angle:

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Draw in all sizes:

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…and also repeat for the back.

 


Now to the rise issue. The back rise should be about one and a half times the length of the front rise….it can be less if your child has a flat bum but never less than one and quarter times the front rise. The instructions say to trim off the top edge from nothing at the center-back, to 1″ at the center-front:

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That won’t give you enough difference in back-to-front rise, but it will result in a “vee” dip at center-front and a “peak” at center-back:

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This means that when the self-fabric waistband is stitched on, there will be strain on the waist fabric in front, and a bubble in the waist fabric in back. Instead of trueing these corners right now, wait ’til the rises are corrected and I’ll show you how to automatically true this area.


 

The bigger problem is there’s no room for the bum. The flat-pattern way to fix this is to “slash-and-spread” the pattern. Splice the back pattern towards the buttocks:

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Then spread:

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Tape the  pattern onto of a plain sheet of  paper. Connect the drafting with a straight-edge and French curve at the  rises (shown after trimming excess paper):

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… and a hip-curve to smooth out the waistline (again shown after trimming….I took these photos as an afterthought, sorry):

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and hemline:

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And voila! This is the shape of a better-fitting knit shorts, with all corners trued for ease of construction:

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Post-script: if you plan on using this pattern please note the grade needs correcting. (The following calculations were done BEFORE adjusting the pattern for shape: this is just to give you an idea of how you can tell adjustments are needed on the original pattern.)

I calculated the waist of the shorts body (pattern front-plus-back, not including seam allowances, doubled for left/right):

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…and the waistband (pattern front-plus-back, not including seam allowances, doubled for left/right):

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…and the measurements don’t match up to the chart given:

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The shorts body grade is between 1/4″ and 3/8″ , and the waistband grade is 3/4″ . This means the shorts body is getting proportionately bigger in relation to the waistband as the sizes decrease.

Size 8 :  you stretch the 19 1/2″ waistband to the 22 3/4″ body to get 21″. That works.

Size 12m: you stretch a 13 1/2″ waistband to a 20″ body to get 15 1/2″? That doesn’t work.

The shorts body  grade is too small.  It’s just slightly over 1/16th of an inch per quarter (front/back/left/right). I would start by doubling the shorts waist grade.

As always, be sure to make a muslin when using any new-to-you pattern!

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4 Responses to How to Correct a Mirrored Knit Shorts Pattern

  1. Abigail says:

    Whenever I read one of your pattern fix posts, I always feel so enlightened. Thanks for taking the time to document these tips.

  2. 7pinedesign@comcast.net says:

    Thank you Abigail, that’s lovely to hear!!!

  3. TC says:

    I just discovered your blog today and it’s a wonderful resource. Thank you for being so generous with your time and expertise.

  4. 7pinedesign@comcast.net says:

    Thank you, that is so sweet!

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