Download Your Cass

Keep reading to discover your ideal size range.

Printable PDF Instructions

If web-based instructions (see below) aren’t your thing, check out the printable PDF instructions, available in the Sie Macht shop. The PDF instructions contain additional material in an easy-to-read format to help you sew your Cass.

Erin wears Cass in size 6/8B. She lengthened Cass 1 inch to accommodate a long waist.

Say Hi to Cass

Cass embodies the heart of Sie Macht’s mission: to create “beyond basic” sewing patterns for bodies of all sizes.

This three-piece sewing pattern features grown-on cap sleeves, a slightly scooped crewneck (screwneck? can that be a thing?), and a subtle rounded hem. The back pattern piece slightly curves over the shoulder to the front of the T-shirt, providing visual interest with a seamline across the front of the shoulders.

Choose a drapey, lightweight knit fabric to highlight how the T-shirt’s boxy, relaxed fit flows over your body. Cass stitches up fast and is destined for tried-and-true pattern status in your wardrobe.

Sew Cass in two size ranges. The “B” range is for bust sizes with a difference of 2 inches (5.1 centimeters) between the upper/high bust and full bust. The “D” range is for bust sizes with a difference of 4 inches (10.2 centimeters) between the upper/high bust and full bust.

The Story Behind Cass

Cass is a shout-out to my husband, Mark Van Handel. Mark’s first apartment was a one-room efficiency on Cass Street in downtown Milwaukee (Wisconsin, U.S.A.). We spent a lot of time on Cass Street as carefree college students. For me, the Cass T-shirt captures these feelings of ease and possibility (hello, pattern hacks!).

Size Chart (Inches)

B Range00/02/46/810/1214/1618/20
Upper/High Bust29.431.633.83639.343
Full Hip34.336.538.84144.147.8
D Range14/1618/2022/2426/2830/3234/3638/40
Upper/High Bust38.3424650545862
Full Hip46.3505458626670

Size Chart (Centimeters)

B Range00/02/46/810/1214/1618/20
Upper/High Bust74.880.285.791.599.7109.2
Full Hip87.292.798.4104.2112.1121.3
D Range14/1618/2022/2426/2830/3234/3638/40
Upper/High Bust97.2106.7116.8127137.2147.3157.5
Full Hip117.5127137.2147.3157.5167.6177.8

Finished Garment Measurements (Inches)

B Range00/02/46/810/1214/1618/20
Back Length (Center Back to Hem)21.121.321.521.721.922.1
Bust, Waist, Hip40.241.743.445.749.453.8
D Range14/1618/2022/2426/2830/3234/3638/40
Back Length (Center Back to Hem)25.725.926.126.326.526.726.9
Bust, Waist, Hip53.257.261.666.170.672.979.6

Finished Garment Measurements (Centimeters)

B Range00/02/46/810/1214/1618/20
Back Length (Center Back to Hem)53.954.254.65555.556.1
Bust, Waist, Hip102105.8110.2116.2125.4136.6
D Range14/1618/2022/2426/2830/3234/3638/40
Back Length (Center Back to Hem)65.465.966.466.867.367.868.3
Bust, Waist, Hip135.2145.2156.4167.8179.2185.2202.2

Fabric Requirements (Yards)

B Range00/02/46/810/1214/1618/20
45 in.
60 in.1*1*1*
D Range14/1618/2022/2426/2830/3234/3638/40
45 in.1.751.752222N/A
60 in.1.751.7522222
*These sizes use only 1 yard when pattern pieces are cut on the quarter fold. For this cutting layout, bring selvages together at the center of the fabric. Place the front and back pattern pieces on the first and third quarter folds. (The fabric is not folded in half.)


Good to Know

All seam allowances are 1/2 inches (1.3 centimeters). The sleeve-opening hem is 1/2 inches (1.3 centimeters). The bottom hem is 1/2 inches (1.3 centimeters).

Cass is drafted for humans with a height of 5 feet 5 inches (165.1 centimeters).

Cass is designed for lightweight knit fabrics with tons of drape. When choosing a fabric, the word of the day is “fluid.” Knits of rayon, bamboo, and ITY are recommended.

For your reference, snip notches at the:

  • Center front neckline
  • Center back neckline

Additional Cass Resources

Step 0: Test Stitches

On two layers of your fashion fabric, test combinations of:

  • (Stretch) sewing machine needles
  • Thread (I suggest a Wooly Nylon-like thread for your bobbin and/or loopers)
  • (Stretch) stitches of different lengths and widths
  • Thread tension
  • Presser foot pressure
  • Presser feet

Don’t fight your fabric or sewing machine. It’s all too easy to overhandle lightweight, drapey knit fabric and stretch it out of shape.

If you’re locked in combat with your fabric, keep testing combos until you find something that doesn’t make you feel like quitting.

P.S. Here’s a blog post on this topic: Sewing knits with a sewing machine: Testing foot-tension-needle combos.

Step 1: Sew Shoulder Seams

With right sides together, sew the shoulder seams. It’s best practice to stabilize the shoulder seam; here’s info on stabilizing seams.

To avoid bulk, the stabilizer should end about 1/2 inches (1.3 centimeters) from the neck edge and the sleeve edge.

Because you’re sewing with drapey fabric, I suggest testing your stabilizer-fabric combo before making a commitment. You don’t want the stabilizer to interfere with the drape of a lightweight fabric. (You may find that skipping stabilizer is OK.)

From the wrong side of the T-shirt, press open the seam allowance. (If serging/overlocking, press the allowance down toward the front hem.) Use a low temperature and low/no steam on a lightweight knit, and don’t linger too long with the iron. We’re avoiding shiny spots. I highly suggest a press cloth!

Step 2: Hem Sleeves

Turn the sleeve hem under 1/2 inches (1.3 centimeters) and stitch. Press gently.

Step 3: Draft and Sew Neckband

It’s time to draft a neckband. The tables below show how long to cut your neckband. The neckband is 2 inches (5.1 centimeters) wide.

Cut the neckband length (see table below) in the direction of greatest stretch. More than likely, this is the cross grain, perpendicular (90 degrees) to the grain and selvage edge.

FYI: The following neckband lengths are approximately 85 percent of the length of the neck seam. If your fabric is supremely stretchy, you might want to reduce the length slightly. (As always, test first.)

Band Length (Inches)

B Range00/02/46/810/1214/1618/20
Band Length191920202021
D Range14/1618/2022/2426/2830/3234/3638/40
Band Length23232424252526

Band Length (Centimeters)

B Range00/02/46/810/1214/1618/20
Band Length495051525353
D Range14/1618/2022/2426/2830/3234/3638/40
Band Length59606162646566

Sew short sides of neckband, right sides together, to create a loop. Gently press open the seam allowance. (For serging/overlocking, press to either side.)

Fold together the long sides of the neckband, wrong sides facing. Baste the long sides together using a narrow and long zig-zag stitch (e.g., 1.5 millimeters wide and 4 millimeters long).

Basting the long edges makes sewing the neckband to the T-shirt easier. Instead of controlling three layers of fabric, you’re only controlling two, because the basted neckband functions as one layer.

Step 4: Prep for Sewing Neckband

Divide the neckband into quarters by folding it in half and folding it in half again. Mark each quarter with a pin. (Pro tip: Use the short-side seam as a quarter marker.)

Turn the T-shirt right-side out. On the T-shirt neck opening, bring together the center front neck notch and the center back neck notch (i.e., front notch touches back notch). Now mark each side neck/shoulder quarters with a pin. (Pro tip: The side seams likely are not the quarter marks!)

Step 5: Sew Neckband

Place the neckband atop the T-shirt neck opening, right sides together and raw edges together. Align neckband quarters to neck opening quarters. Pin together with the pinheads on the right and the bulk of fabric to the left, and remove extra quarter-marker pins.

(Pro tip: I sewed a better neckband when I further divided the neckband and neck opening into eighths. To do this, after you’ve pinned together the neckband and neck opening quarters, gently pull the neckband and neck opening apart between pins, drawing the pins to touch. Congrats, you’ve divided a quarter into an eighth! Pin together the neckband eighths and neck opening eighths.)

Reminder: The neckband is shorter than the neck opening. When sewing the neckband to the neck opening, gently stretch the neckband to the same length as the neck opening. Do not overstretch the neckband!

You’ll likely need to gently stretch each neckband quarter both in front of and behind the presser foot. This action calls for two hands, and for me, right hand in front of the presser foot and left hand behind the presser foot works best.

Remember that the tension you create behind the presser foot is to gently stretch the neckband to the same length as the neck opening. You are not pulling the fabric under the needle; let the feed dogs do the work. Take it slow, and you’ll do great. And if this is a new technique or a new fabric for you, by all means practice!

Step 6: Press Neckband

From the wrong side, gently press the seam allowance toward the T-shirt interior (press in the same direction if serging/overlocking). Pressing with a tailor’s ham is a nice way to respect this rounded opening. Take extra care to not stretch the neck opening during pressing; iron heat + stretching = wonky neck opening. (I speak from experience.)

At this point, you can stitch down the seam allowance from the right side, trim it away, or finish the raw edge with a zig-zag or serger/overlocker stitch. Sewist’s choice!

Step 7: Sew Side Seams

Use a stretch stitch. Straight stitches in this diagram are for illustrative purposes.

Pin the side seams from the underarm to the bottom hem, right sides together. Starting at the underarm, sew this seam with a 1/2 inch (1.3 centimeters) seam allowance.

The side seam stitches go over the sleeve hems. The sleeve hems are sewn together to make the circle for the sleeve opening. Make sure you sew over the hem allowance with the side seam.

From the wrong side, gently press the seam allowance open. (If serging/overlocking, press the seam allowance toward the back of the T.)

Step 8: Hem T-Shirt

Turn under (wrong sides together) the bottom hem 1/2 inches (1.3 centimeters). Stitch the hem from the right side.

Give the hem a gentle press and trim excess hem allowance if desired.

Step 9: Celebrate!

Pop on that T-shirt and check out your reflection! You made that! Way to go!

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