Old Windmill block

The Old Windmill block is made up of 16 half square triangles and fits a four patch grid layout. In this calculator you may choose to sew half square triangles from squares or triangles cut from strips. To do the calculations, javascript must be enabled. While every effort is made to be sure of accuracy, I am unable to test every variation. Before you cut up large amounts of fabric, cut and sew a test block or two. If you find any errors, please email me at "jeanne@myquiltgenie.com".

Settings

Cutting Method
Size
Number of blocks
Fabric width

Fabrics

fabric 1Fabric 1: Cut 1 strip 2-3/8 inches wide. Subcut into 8 squares.
fabric 2Fabric 2: Cut 1 strip 2-3/8 inches wide. Subcut into 2 squares.
fabric 3Fabric 3: Cut 1 strip 2-3/8 inches wide. Subcut into 2 squares.
fabric 4Fabric 4: Cut 1 strip 2-3/8 inches wide. Subcut into 2 squares.
fabric 5Fabric 5: Cut 1 strip 2-3/8 inches wide. Subcut into 2 squares.

Instructions

Figure 1 - half square triangles from squares

Half Square Triangles from squares

  1. Match one square each of fabric pairs listed below, right sides together.
  2. Draw a diagonal line from corner to corner on wrong side of lighter fabric.
  3. Sew 1/4 inch seam on both side of diagonal line.
  4. Cut units apart on drawn diagonal line.
  5. Press seam to one side.
  6. Makes 2 units per square pair.
Each block needs 4 half square triangle units per fabric pair listed below. Make 4 total for each pair.
  • Fabrics 1 and 2
  • Fabrics 1 and 3
  • Fabrics 1 and 4
  • Fabrics 1 and 5
Figure 2 - block layout

Old Windmill block final instructions

Layout block pieces using 4 half square triangles of each fabric pair as shown in diagram. Sew first columns, then rows using a 1/4 inch seam. Press seams to one side.