Check out this tutorial for how to hack the Cass T-shirt PDF pattern with a ruched drawstring feature at the shoulder seams.

Another post, another way to hack the Cass tee! This time it’s a ruched drawstring tutorial for our fave me-made T-shirt.

The shoulder seam on Cass sits on the front of the shoulder/upper chest — not the top of the shoulder. It’s an interesting design detail, and it becomes even MORE visually appealing with drawstring ruching.

I love how the tight ruching of my tee pulls the neckline into an almost square shape. To my eyes, this treatment also mimics a shrug or bolero in the shoulders. Do you see that, too?

When it comes to adding a ruched drawstring element, you could:

  • Use seam allowances for casings (aka, drawstring tubes).
  • Stitch on a casing as a separate fabric pattern piece (probably a skinny rectangle).
  • Sew a pintuck as a casing.

And, there probably are other ways to add a ruched drawstring that I haven’t thought of. Sewists are an inventive species. (If you know another way, please share in comments!)

Let’s walk through how the Cass T-shirt you see here came to be.

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The seam allowances at the shoulders turned into casings for this ruched drawstring sewing pattern hack.

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How to Sew a DIY Ruched Drawstring T-Shirt

Here’s how I added ruching at the shoulders to a Cass T-shirt:

1.) I traced off the front and back pattern pieces. For the record, the pictured shirt is size 6/8B.

2.) I cut out front and back pattern pieces.

3.) I drew in shoulder seamlines on the front and back pattern pieces.

4.) I taped together the front and back pieces at the drawn-on seamline. (It doesn’t matter which pattern piece is on top.)

I turned the striped fabric 90 degrees for the back pattern piece. This is what I did with the Cass featured in this post: Striped Cass T-Shirt and New Ginger Jeans. The perpendicular lines create a cool juxtaposition at the seams, and I didn't have to try to match stripes across the seams!
I turned the striped fabric 90 degrees for the back pattern piece. This is what I did with the Cass featured in this post: Striped Cass T-Shirt and New Ginger Jeans. The perpendicular lines create a cool juxtaposition at the seams, and I didn’t have to try to match stripes across the seams!

5.) I taped a piece of scrap paper under the sleeve. This is to accommodate a slightly longer sleeve. I made the sleeve longer to maximize the ruching effect. For D-range sizes, do not add extra sleeve length; the grown-on sleeve for the D range is already quite long and you don’t want it to get out of proportion.

6.) I drew a straight line across the sleeve connecting the original ends of the underarms. This line will negate the rounded sleeve hem.

7.) I extended the edge of the underarms toward the sleeve. The sleeve-side corners are 90 degrees; I drew a straight line onto the scrap paper that was perpendicular to the side of the pattern piece.

8.) At the intersection of the line connecting the original underarm ends and the seamline, I measured out and marked 2-1/2 inches.

Here's how I hacked the Cass T-shirt pattern to straighten the sleeve hem.
Not to scale.

9.) At the 2-1/2 inches mark, I drew a line that:

  • Was parallel to the line connecting the underarm ends.
  • Connected the underarm extension lines.

This is the edge of the sleeve, including hem allowance.

Note: I finished the sleeve hems and bottom hems with a coverstitch. (I recently acquired a coverstitch machine, woot woot!) Because I’m a new coverstitch machine user, I made things easy on myself and increased the sleeve and bottom hem allowances to 1 inch, up from the pattern’s 1/2 inch. So, if you’re finishing the sleeve hem with a 1/2-inch allowance, measure out 2 inches instead of 2-1/2 inches.

The B-range Cass gets a sleeve extension for the ruched drawstring hack; the D-range Cass does not get a sleeve extension.

10.) I cut away excess paper around the extended sleeve.

11.) I cut apart the front and back pattern pieces at the shoulder seam. At this point, the shoulder has NO seam allowance.

12.) I made the shoulder seam allowances 1 inch. The 1-inch seam allowances become the drawstring casings. You can:

  • Use extra paper to add the 1-inch seam allowance to the paper pattern pieces.
  • Write on the front and back pattern pieces at the shoulder edge: “Add 1 inch seam allowance.” (That’s what I did.)

13.) Optional: I cut off the curved bottom hem to make it straight and added a 1-inch hem allowance. (A straight hem is easier to coverstitch vs. a curved hem.)

I cut off the curved hem of the Cass T-shirt. The straight hem was easier for me to coverstitch as a new coverstitch user.

14.) I cut out my fashion fabric — front, back, and neckband.

15.) I sewed the front and back sleeve hems. This way the edge of the casing is finished. If you sewed the shoulder seams first and then finished the hems, the casings would be sealed. Make sense?

16.) I sewed the shoulder seams with a 1-inch seam allowance. With my shirt, the seam allowance is on the inside (sewn right sides together); this puts the drawstring casings on the inside. You could stitch wrong sides together and put the casings on the outside, too.

17.) I pressed open the shoulder seams. You also could press the SA to one side and have one drawstring casing instead of two.

The ruched drawstring pattern hack pulls the neckline into a square shape. You don't have to pull the ruching as tight, of course!

18.) I stitched down the seam allowances from the right side to create the casings.

19.) I made four drawstrings. My drawstrings are 1-by-20-inch strips of fashion fabric cut on the cross grain (stretchy is good). I think 20 inches is generous; measure your shoulder seam before committing to a length. Longer is better because you can trim excess drawstring. I found the fabric too bulky to sew right sides together and turn right side out. Instead I folded WRONG sides together (the long way) and stitched the strips on my serger with a four-thread overlock.

I cut the drawstrings to be 20 inches long.

20.) I inserted the drawstrings into the casings. I used a plastic elastic threader. I played around with drawing up the casing at this point to experiment with how I wanted the ruching to look. Pull excess length into the neckline to even out the ends that go through the sleeve hem. (See how you could make the drawstrings extra long, even them out, and cut off the excess at the neckline?)

21.) I basted the drawstrings in place at the neckline. Trim away excess drawstring if necessary.

22.) I sewed the neckband.

23.) I sewed up the side seams.

24.) I hemmed the bottom edge.

This DIY ruched drawstring hack gives the shoulders a shrug or bolero look.

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Best Serger Hems for Thin Knit Fabrics

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I am excited to try this drawstring ruching hack on other me-made garments.

Final Thoughts About the Drawstring Ruching Hack

I kinda wish I would have lowered the underarm 1-2 inches. Because the ruching makes everything tighter, the armpit ALSO is tighter, and it feels/looks a little off on this relaxed shirt. If you’re sewing a D-range Cass and want to try the drawstring shoulder hack, I suggest lowering the underarm even more — maybe 3 inches? Test and see.

The drawstrings are intense on this shirt, to the point where they look almost too heavy. I think this is because they fall on the front of the arm vs. the top or side of the arm (where they would sit if the shoulder seams were on the top of the shoulders).

I thought for a hot minute about braiding or weaving some embroidery floss to make the drawstrings. Still think this would be a super cool and ultra personalized detail. Please, somebody do this and tell me about it!

If you like this post, you’re going to LOVE LOVE LOVE the Cass T-Shirt and Book of Hacks. It’s a PDF sewing pattern (in misses and plus sizes!) and instruction e-book that shows you how to modify the pattern five different ways.

The whole megillah is basically six patterns for the price of one. And did you know there are even more Cass hacks/T-shirt tutes on this here website? Yup, true story.

Check this:

OK, over to you, sweet sewist: How do you feel about ruched garments? I’ve never sought them out, but I kinda love how this tee turned out.

P.S. No post next week, my doves. I’m on August holiday.