Half-square triangles are the building block behind pinwheels, chevrons and sawtooth stars. This method sews before cutting, so the stretchy diagonal never gets pulled.
Supplies
- Quilting cotton in 2 contrasting colors
- Rotary cutter, mat and a square ruler
- Fabric pencil or hera marker
- Sewing machine with a ¼″ foot
Quilting terms
| RST | right sides together |
| SA | seam allowance (¼″) |
| HST | half-square triangle |
| FQ | fat quarter (18″ × 22″) |
| WOF | width of fabric |
| Press | iron up and down, no sliding |
Instructions
Tick each step when you finish it: the page remembers where you stopped.
- Cut Cut one 3⅞″ square from each fabric (finished size + ⅞″).
- Mark Draw a diagonal line corner to corner on the wrong side of the light square.
- Sew Place the squares RST. Sew ¼″ from the line on both sides.
- Cut apart Cut on the drawn line with the rotary cutter. You now have 2 HST units.
- Press and trim Press toward the dark fabric, trim the dog-ears and square each unit to 3½″.
- Make a pinwheel Sew 4 HSTs into 2 rows, rotating each unit a quarter turn, then join the rows. That is a 6″ finished pinwheel block.
Tip: Starch the squares before cutting. Stiffer fabric keeps the diagonal from shifting under the presser foot.
