Blockalogue: Pinwheel Block Tutorial

A PDF version of this tutorial, containing diagrams instead of photos, is available in my Craftsy store: Pinwheel Quilt Block PDF Pattern.

Pinwheel Block

The Pinwheel block is another favourite of mine (aren't they all?). It looks great as a large feature block for your quilt, or as a series of smaller blocks in a border. The pinwheel works well in most fabrics, though I would suggest taking care with larger prints or directional fabric.

Cutting Instructions

These instructions are for a Pinwheel block of any size. Two squares of each fabric, cut to the ‘Cut Size’, are required for a single Pinwheel block. Use the formula below to determine the cutting size needed.

Cut Size = (Finished Block width /2) + 1’’
Note: Technically you only need to add 7/8'' instead of 1'', but it's easier to cut a little larger and trim to size later.

For example:

If the desired Finished Block is 12’’ (or an unfinished size of 12 ½’’), then:

Cut Size = (12/2) + 1

       = 6 + 1

 = 7

Cut two 7’’ squares of Fabric 1 and two 7’’ squares of Fabric 2.

Cut two squares of each fabric.

Piecing Instructions

Use a ¼’’ seam allowance unless otherwise stated.

On the wrong side of each Fabric 1 square, draw a line along one of the diagonals.

Draw another line ¼’’ from either side of the centre diagonal.

The pink line is the first diagonal you draw. The blue lines are 1/4'' either side of the pink.

Pin one Fabric 1 square to one Fabric 2 square, with right sides together and raw edges aligned.

Place the Fabric 1 and Fabric 2 squares right sides together

Sew along the ¼’’ lines (represented by the blue lines in the images above).

Cut along the centre line, producing two half-square triangles (HSTs).

Cut along the centre diagonal (pink line)

Two HSTs have been created

Press the seam either open or toward the darker fabric. Pressing open can help reduce bulk in the seams. I usually press towards the darker fabric for all seams of the pinwheel except for the very last one, which I press open.

Open HSTs

Repeat for the remaining one Fabric 1 and one Fabric 2 squares for a total of four HST units.

Trim each HST to size. Use the following formula to determine the trim size:

Trim Size = (Finished Block width /2) + 1/2’’

For example:

If the desired Finished Block is 12’’, then:

Trim Size = (12/2) + 1/2

         = 6 + 1/2

       = 6 1/2''

Hint: Place the 45 degree line of your ruler against the diagonal seam to ensure the HST is trimmed evenly.

Trim HSTs using the 45 degree line as a guide

Trimmed HST

Sew two HST units as shown below, pressing the seam open or toward the darker fabric.

Sew two HSTs together

Repeat for the remaining two HST units.

Join the two units, taking care to line up the middle seam and keep the points of each triangle.

Sew two units together to make the pinwheel

As you can see, while this is a quick and easy block to piece, it can add a lot of interest to your quilt.

I hope you enjoyed this Blockalogue pattern and tutorial. I'd love to hear what you think so please let me know by either leaving a comment below, or on the pattern on my Craftsy page (Pinwheel Quilt Block PDF Pattern).