How to make a t-shirt

1. Materials & tools

Materials (adult M)

• Knit fabric (cotton jersey, French terry, etc.) — about 150 × 100 cm (60 × 40 in)
• Optional: ribbing for the neckband — about 50 × 10 cm (20 × 4 in)
• Ballpoint / stretch machine needle and (ideally) stretch or zigzag stitch

Tools

• Sewing machine (or needle and thread)
• Fabric marker or pencil
• Ruler and scissors
• Iron
• Pins or clips

2. Make the pattern (auto-generated in Katagami)

With the Katagami pattern tool, you just enter the finished size and it drafts a seam-allowance-included pattern, tiled to print at actual size on Letter or A4.

1. Open the tool
   Open the pattern tool and choose “Adult clothes” → “T-shirt” from the tabs at the top.
2. Enter the size
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3. Set the seam allowance
   Use the slider at the bottom (beginners: 1.0–1.5 cm / about 3/8–5/8 in).
4. Print
   Press “Print (actual size)”, then in the print dialog set Scale = 100% and turn “Fit to page” OFF. Check the 50 mm calibration box on the first guide sheet with a ruler.

3. Cutting the fabric

1. Trace the pattern
   Trace the cut line and seam line onto the wrong side of the fabric. Align the grain with the grainline; for knits the most stretchy direction usually goes around the body.
2. Cut
   Cut the back on the fold (1), the front on the fold (1) and 2 sleeves. Mark the notches on the armholes.
3. Use a stretch stitch
   Sew with a narrow zigzag or stretch stitch, or a serger, so the seams stretch with the fabric.

4. Sewing

4-1. Sew the shoulders

1. Place front and back right sides together and sew both shoulder seams.

4-2. Set in the sleeves

1. Open the body out flat. Matching the sleeve notch to the shoulder seam, pin each sleeve to the armhole, right sides together, and sew along the curve.

4-3. Sew the sides and underarms

1. Fold right sides together and sew each side from the sleeve cuff down to the hem in one continuous seam. Match the underarm point.

4-4. Finish neckline, cuffs and hem

1. Neckline: attach a ribbing band, or turn under and topstitch with a twin needle / zigzag.
2. Cuffs and hem: turn under and topstitch. Press lightly — avoid stretching the fabric as you sew.

5. Tips & variations

• Baste first: knits are forgiving but the neckline and armholes are easier to adjust before final stitching.
• No serger? A narrow zigzag works fine; just don't pull the fabric through the machine.
• Change the look: lengthen for a tunic, shorten the sleeves for a tee, or widen the body for an oversized fit.