It's launch day for the Cass T-Shirt and Book of Hacks. Read all about the T-shirt PDF pattern, its five sewing pattern hacks, and the 42-page e-book that will guide your way as you sew them all.

It’s launch day for the Cass T-Shirt and Book of Hacks! We made it!

Pour yourself a beverage, tuck into a comfortable seat, and read all about the T-shirt pattern, its five hacks, and the e-book that will guide your way as you sew them all.

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What is the Cass T-Shirt Pattern and Book of Hacks?

Sie Macht Cass T-shirt PDF sewing pattern
Sie Macht Cass. The T-shirt features a rounded hem.
Sie Macht Cass front technical drawing
Sie Macht Cass back technical drawing

Let’s start by talking about the star of the show: Cass.

Cass is a relaxed-fit T-shirt with grown-on sleeves, a gently rounded hem, and eye-catching shoulder seams that roll to the front of the garment. It’s only three (!) pattern pieces: front, back, and neckband.

Now, when you buy your Cass, you’re actually getting a PDF sewing pattern on steroids.

Not only do you get the sewing pattern and instructions for how to sew the tee, but you also get instructions for how to hack Cass five different ways. It’s an all in one e-book that features clear illustrations for the trickiest sewing steps.

FYI, Cass comes in sizes 00/0B to 18/20B (misses) and 14/16D to 38/40D (plus). The hacks work for both size ranges, and the pattern mods include knit and woven garments, tops and dresses (details on each hack below — keep reading). So many lewks for so many bodies!

What Makes Cass Special?

When I designed Cass, I knew it had to be not just good but great, because there are many amazing indie tee patterns out there. Y’all got choices.

Here’s what sets Cass apart:

  • It’s only three pattern pieces, which means it’s fast to cut out and fast to sew. Hello, instant gratification! (Some of the hacks have more pattern pieces, BTW.)
  • You won’t have fitting woes, thanks to Cass’ relaxed style. The tee is the same width from the bust to the hip, with lots of ease for both zones of your body.
  • The two size ranges almost guarantee you’ll find a Cass size that works for your body. The B range accommodates busts from 31.5 inches (79.9 centimeters) to 45 inches (114.3 centimeters) and hips from 34.25 inches (87.2 centimeters) to 47.75 inches (121.3 centimeters). The D range accommodates busts from 42.25 inches (107.3 centimeters) to 66 inches (167.6 centimeters) and hips from 46.25 inches (117.5 centimeters) to 70 inches (177.8 centimeters).
  • The instructions feel like a sewing friend walking you through a project. You’ll feel relaxed and confident. Sewing is F-U-N; the directions should be, too.

You can sew Cass quickly, with a smile, and it’s going to fit. What more could a sewist ask for?

Oh yeah… don’t forget about how the e-book basically is six sewing patterns for the price of one.

Who Can Sew Cass?

I’m no gatekeeper when it comes to stitching, but here’s who I think would have the best time sewing Cass and its five hacks:

  • If you’re a novice sewist of knits and want to level up your skills with drapey knit fabrics, Cass will be fun for you. Knits (especially drapey knits) can be tricky; start by sewing easy, straight seams.
  • If you’re looking for a stash-buster project, Cass could be the ticket. You could use up smallish cuts of fabric on either the front or back pattern piece.
  • If you want to experiment with pattern hacking, the Book of Hacks will rock your socks off. I promise it will get you thinking about how to hack existing patterns in your library.
  • If you’re looking for a wardrobe-staple pattern that you’ll eventually be able to make in a few hours, give Cass a go. Dream up your tee in the morning, and sew it in the afternoon. Wa-bam, you’ve got a new shirt for going out.
  • If you’re a sewist who likes to wear amorphous, loose garments, Cass will treat you right. Hey, body con isn’t for everybody all the time, and you really can’t argue about the comfort of a relaxed T-shirt.

What Fabrics Can I Use?

Cass is designed for lightweight knit fabrics with mega drape. The T-shirt is cut to be boxy and relaxed, and the flow of fabric over your body’s curves is what gives it the teeny-tiniest bit of sex appeal.

Suggested fabrics include:

  • ITY knit
  • Knit blends featuring rayon, bamboo, silk, or linen
  • Double-brushed poly knit
  • Lightweight performance/athletic knit

The big idea is that the generous ease of this T-shirt design flows over your body. Fabric that has too much body will stand away from your body, and your Cass will loose its slinkiness.

When it comes to choosing WOVEN fabric for Cass hacks, stick with drapey options, too: rayon, silk, lyocell, etc.

Drape = good. Body = less good.

What is Included When I Buy the Cass T-Shirt and Book of Hacks?

ZOMG you get so much stuff.

  • Print-at-home PDFs of the B- and D-range patterns (2 files)
  • Copy-shop PDFs of the B- and D-range patterns (2 files)
  • 42-page e-book PDF (1 file)

And inside the e-book you will find:

  • Glossary of sewing terms
  • Size charts in inches and centimeters
  • Finished garment measurements in inches and centimeters (T-shirt only)
  • Pattern piece census
  • Suggested fabrics
  • Suggested tools and notions
  • Fabric requirements in yards (T-shirt only)
  • Fabric-cutting diagrams (T-shirt only)
  • Printing guidance
  • Exhaustive instructions for Cass and its five hacks
  • Photos of the hacks on misses- and plus-sized models (with model measurements and sizes for reference)


What are the Cass Hacks?

I am SO GLAD I finally get to share them with you!

For your reference:

B-Range Model (me, Erin VH!)
Size: 6/8B
High Bust: 32 inches
Full Bust: 34 inches
Waist: 28 inches
Full Hip: 38 inches
Height: 5-feet-5

D-Range Model (my SIL, Cheryl!)
Size: 18/20D
High Bust: 44 inches
Full Bust: 45.5 inches
Waist: 40 inches
Full Hip: 49 inches
Height: 5-feet-8

Cass book of hacks half-tie dress D range front
Cass B-range T-shirt hack half-tie dress front
Cass book of hacks half-tie dress D range back

The Half-Tie Dress

The Half-Tie Dress features a tie belt that comes out of center front and center back seams. I wanted an easy-wearing T-shirt dress that wasn’t completely shapeless, and ties or a belt that came out of the side seams seemed too obvious.

The fabrics here are two different colorways of the same material: hatchi stretch knit. It’s a super-soft-to-the-touch blend of polyester, rayon, and spandex.

Cass D-range t-shirt hack cropped front
Cass T-shirt book of hacks cropped B-range front
Cass T-shirt cropped with drawstring B range back

The Cropped Cass

The hem of this hack, which features a fun drawstring, falls between the waist and high hip. I was inspired by the shape of cropped football jerseys — boxy with squared-off sleeves. I think this looks so cute with high-waisted pants.

The D-range fabric is a rayon-blend French terry with a tie-dye motif. The B-range fabric is a moderately drapey mystery knit from my fabric stash.

Cass t-shirt caftan hack B-range front
Cass caftan hack D-range front
Cass caftan hack B-range back

The Cass Caftan

This hack for wovens features a neckline facing for the V-neck and sassy side slits. I knew Cass’s straight-up-and-down shape would make a fab caftan, but I also knew that it needed sexy details to keep it from looking like a sack — hence the neckline and slits.

The D-range fabric is a batik-dyed rayon challis (different colorway, same brand). The B-range fabric is cotton quilting (!!!) fabric from Kaffe Fassett (I was mesmerized by this colorway and went for it).

Cass hack D-range front the gathering T-shirt
Cass hack the gathering t-shirt B range
Cass hack the gathering T-shirt back detail

The Gathering T-Shirt

What I love about this hack is that the design detail — gathering — is found in the front and back. The instructions for this hack show you how to add length to seams to create those sweet gathers. It gives me floaty, babydoll-dress vibes.

For the D-range, the stripe is a rayon knit and the blue is a poly ITY knit. The B-range fabric is an activewear poly-spandex mesh from Joann.

Cass T-shirt hack woven tee B range
Cass T-shirt hack woven tee D range
Cass hack woven T-shirt back D range

The Woven T-Shirt

Transforming Cass into a woven T-shirt was my No. 1 priority when I started devising hacks. The big thing I had to decide was how to get into and out of it without a stretch neckband. The solution was a slit at the back neck opening, secured with a snap or hook and eye. This hack is easy to wear and makes me feel polished.

The D-range leopard print fabric is a rayon challis from our sewing idol, Mimi G. The B-range fabric is a rayon from my fabric stash.

What Happened to the Free Cass Pattern?

Yes, Cass used to be free on the site. You give me your email, I give you the pattern. It was a way to build my email list.

I decided to include the Cass pattern with the hack book to provide sewists with greater value. It made sense to me to roll everything together: the pattern AND its modifications.

For the record, the free Cass and the paid Cass are the same pattern.

And I think that’s about all you need to know about the Cass T-Shirt and Book of Hacks. Thanks for reading, thanks for BUYING, and thanks for sticking with me as I put together this pattern and e-book. I’m so excited to get it into your hands and to hear what you think about it — tag me @sie.macht.sewing and #smcass.



P.S. If you want even more Cass content, including more Cass hacks, check out these articles: