How to Sew Pinwheel Quilt Blocks — a Tutorial

by cdmwriter on December 6, 2012

There’s something so cheerful and festive about the pinwheel block — and it’s also an easy block that is well within the abilities of beginning quilters. Pinwheels look great in quilts for children or in Christmas projects.

The block is made by sewing together four half-square triangle blocks in such a way that the block seems to be spinning like the pinwheels children get at school fairs. The only tricky part is getting all the triangle points to match at the center of the block. The key to perfectly aligned points is learning how to sew a scant 1/4″ seam.

Here are a few pinwheel blocks I’ve made:

[Show as slideshow]

Click on an image to see a larger view.

And here’s a detail of a scrappy pinwheel quilt from +Eva+ on Flickr.com that uses a lot of different fabrics. Notice how she used the white fabric to unify all the different colors. That’s what makes this quilt work.

Pinwheel Block Cutting Sizes

Each pinwheel block starts with four half-square triangle blocks. Learn how to sew a half-square triangle block.

If you’re going to make your triangle blocks from fabric squares, which is the method I usually use (and the method I teach in the tutorial above), you will need four fabric squares to make each pinwheel block:

Two light squares
Two dark squares

Each set of four squares makes four half-square triangle blocks, which you sew together to make the pinwheel.

Here’s how large to cut the squares to make a finished pinwheel block of various sizes:

6” finished block: cut squares 4”
9” finished block: cut squares 6”
12” finished block: cut squares 7”

These square sizes yield slightly larger triangle blocks than some quilting teachers recommend. That way, they give you a little extra room for trimming down the blocks after sewing. I don’t know about you, but I always feel glad to have the extra room when I’m squaring up my blocks.

Step-by-Step Instructions

Each pinwheel starts with four half-square triangle blocks.

Before you sew, lay out the triangle blocks as they will appear in the block. Make sure the pinwheel “spins” the way you want it to.
I sew the top two blocks together, then the bottom two blocks, as shown here. To sew a pair of blocks, lay them with right sides together, then sew with a scant 1/4″ seam. After you sew them, press the seam allowance to one side.
Sew together the bottom left and bottom right triangle blocks in the same way you sewed the top two blocks. You will now have two larger units: one on top, and one on the bottom. Press the center seams on the top and bottom units in opposite directions, so the units will nest together when you sew the next seam.
Lay a top unit and bottom unit with right sides together and sew down the long side. Press. The block should now look like this: