Double Pinwheel Quilt Block Pattern

From our Free Quilt Block Patterns Library

by Julie Baird

Skill Level: Confident beginner

Grid: 2x2

The Double Pinwheel quilt block is made completely of quarter square triangle units in three fabrics. The QSTs form a small pinwheel and the HSTs a large one, hence the name.

You may also know this block as:

Old Windmill
Windmill or...
Whirligig

This same block can be colored in several other ways using two or three fabrics to create a number of variations in look of this block. Those variations and their cutting instructions are below. There are 5 different block sizes included here.

This block would make an adorable baby quilt.

In the larger block sizes, it'd be quick to whip up. As smaller blocks they'd be great for a block exchange with your quilting bee or guild.

General Instructions

All seams are 1/4".

Several abbreviations are used:

SA - seam allowance

QST - quarter square triangle

RST - right sides together

When instructed to press, first press the pieced unit flat to set the seam. Then open the patch, pressing from the front. Seam allowances are pressed to the dark fabric unless otherwise noted.

The instructions that follow are for a traditionally pieced block, though your Double Pinwheel could easily and efficiently be paper pieced. (Click here for those instructions and the free downloadable paper piecing patterns.)

Step 1: Cut the fabric patches

Double Pinwheel block design

The measurements in the chart below are exact. If your quarter inch seam allowance is reliably accurate, use these measurements.

All the numbers in the chart below represent squares (to make the chart easier to read).

Personally, I prefer to make quarter square triangles (QST) with oversized patches, sew them, and then trim to the perfect size.

So if a patch for #1 is 4-1/4", I added a quarter inch and cut it 4-1/2" x 4-1/2". Necessary subcuts are at the end of each row for #1-#3.

Stitch as directed in the instructions.

After sewing the QSTs, there's a chart so that you can check that they are accurate, trimming if needed.

			Cutting Chart for a Double Pinwheel Quilt Block ~Traditional Piecing ~
Patch	Fabric	Qty	Finished Block Size					Sub Cut
Patch	Fabric	Qty	3"	4"	5"	6"	8"	Sub Cut
1	A	1	2¾"	3¼"	3¾"	4¼"	5¼"
2	B	1	2¾"	3¼"	3¾"	4¼"	5¼"
3	C	2	2⅜"	2⅞"	3⅜"	3⅞"	4⅞"
Unfinished Block Size			3½"	4½"	5½"	6½"	8½"	na
Grid Size			1½"	2"	2½"	3"	4"	na

My go-to thread for all my piecing is...

After the sub-cutting they look like this.

Cut patches for the Double Pinwheel block

Step 2: Assemble the units

With RST, align the edges of one #1/white dot and #2/blue dot patch. So that the patches end up in the proper position, stitch with #2/blue on top and feed the blunt edge into your sewing machine first.

That red arrow is pointing towards my anchor cloth.
I always use one.

Press the unit flat. Then press it open with the seam allowance towards #2/blue dot.

The edges of this stitched pair should be straight and even.

The long edge of the QST should be straight

This edge is nice and straight

With RST, align the long edge of this pieced unit with the long edge of the #3/yellow triangle.

Stitch.

The red arrow below points to my anchor cloth.

Press the unit flat to set the seam. Then press open with the seam allowance towards the #3/yellow patch.

Repeat for the three remaining units.

The QSTs look like this before trimming.

For this 6" finished sample block, this unit should measure 3-1/2" square. Trim if needed.

Check for Accuracy

If you used the exact size for cutting the original squares, measure your block to confirm it is the correct size (see 'Size, edge-to-edge' in the chart below).

Check for Accuracy Whirlwind QST units
	Finished Block Size
	3"	4"	5"	6"	8"
Center (Midpoint)	1"	1¼"	1½"	1¾"	2½"
Size, edge-to-edge	2"	2½"	3"	3½"	4½"

If you added a 1/4" to the dimensions to create generous squares, it's time to trim our patches to 3-1/2" for our 6" finished sample. Use the 'Center (Midpoint)' measurement from the chart above.

Click here for a review on trimming quarter square triangles if needed.

Click here for a refresher on trimming a QST to size.

Step 3: Assemble your Double Pinwheel quilt block

Arrange your Double Pinwheel quilt units so that there is one #1/white dot triangle on the outside edge of each side.

The diagonal seams will nest for each two block row. Pin them if needed. Stitch. Press flat and then open with the seam allowance towards Fabric C/blue dot.

Your rows look like this.

Again, the seams in the center of the block will nest which makes matching the center seam allowances so much easier. Pin if needed. Stitch the rows together.

Press flat to set the seam. Then twirl the center seam allowance to distribute the bulk.

When the seam is twirled or pinwheeled it forms a 'mini-pinwheel'. In this block, all the seams are pressed counterclockwise.

This is how your Double Pinwheel quilt block looks from the back.

Double Pinwheel quilt block from the back

The twirled seam allowances form a pinwheel on the back

And this is the finished Double Pinwheel quilt block from the front.

Common Variations

For such a simple design, there are many variations on the Double Pinwheel quilt block.

The QST.1-3 fabrics are identified for all the blocks below.

Simply choose your block and a size, make your fabric choices and you're ready to make any block on this page!