Quilt blocks are often composed of simple shapes and these simple shapes can be arranged in all sorts of different ways to create different block designs. If you are able to identify the shapes within a traditional block and learn how to make them in any custom size then you won’t have to rely on purchasing quilt patterns. The two most common simple shapes found within quilt blocks are the square, and the half square triangle (or HST). I will use these two shapes as a starting point in this tutorial. In the image below we have the square on the left and the HST on the right. Once you learn the basics of these two easy shapes you can use them to recreate many traditional quilt blocks or you can play around by arranging them in fresh new ways to make new block designs of your own.

Simple Traditional Quilt Blocks made from only squares and HST’s

Custom Block Sizes

The cool thing about making blocks from scratch is that you have the freedom to make the blocks in any size you desire. This allows you to have control over the scale of your overall quilt design. Maybe you want to make a more minimally designed quilt with a small amount of large blocks. Or maybe you want to be a maximalist and make tons of tiny blocks. Maybe something in between? It’s totally up to you and it’s also pretty easy to figure out. I’ll use the shoofly block shown below as my example.

The shoofly block is made from nine patchwork squares (quilters refer to this as a 9-patch block). Referring to the shoofly illustration above we can identify:

4 white squares

1 pink square

4 sage and white HST’s

Understanding Seam Allowance

Okay so, first things first. When sewing quilt pieces and blocks together the standard seam allowance is 1/4”. In the world of quilting the terms finished size and unfinished size pop up often. When blocks and the pieces that make up a block are sewn together they become 1/2” smaller due to the seam allowance. So unfinished refers to the size of a block or the pieces within a block before they’ve been sewn together. Finished refers to the size after they’ve been sewn together. To make it less complicated, I prefer to think in terms of finished size and then simply add 1/2” to that when considering the unfinished size.

Now back to our shoofly example. Let’s make a 9” finished shoofly block. In this case, all of the squares and HST’s within the block need to be 3” finished (because 3+3+3=9). The squares are simply cut to their unfinished size of 3.5”. But how to make the HST’s? There are all kinds of different methods that I encourage you to look into. The method I’m sharing in this tutorial makes two at a time. HST’s are often made from contrasting light and dark colors. To make a pair of HST’s you begin by cutting a pair of contrasting squares 1” larger than your desired finished HST size.

HST Formula

finished HST size + 1”

For a 9” finished shoofly block we need 3” finished pieces:

3” + 1” = 4”

Remember that this formula makes two HST’s at a time so each pair of light and dark squares will yield 2 HST’s. For the shoofly example we need 2 pairs of sage and white squares to make 4 HST’s.

Assemble HST’s

Begin by placing a darker square on your work surface. Then place a lighter square on top of it aligning all the corners. Center the middle line of a 1/4” seam ruler on opposite corners. I like my ruler by Fons & Porter but I don’t do affiliate links so please do a search for it if you’re curious about it. I don’t have a lot of fancy tools but this is one I use very often. Use a mechanical pencil (or a sharp pencil) to draw a line on both sides of the ruler as shown in the photo on the left below. If you don’t have a 1/4” seam ruler you can instead draw a diagonal line from corner to corner, then draw diagonal parallel lines 1/4” above and below the center line. Repeat for the other pair of squares.

Sew along both of the diagonal pencil lines.

Now carefully cut between the two pencil lines. Open out the HST’s and press the seams open. If you prefer to press your seams to the side that’s great too.

Trim

The next step is to trim the HST’s. This step is important because at this point the HST’s are a little big. They need to be squared down to their proper size which in this example is our unfinished size of 3.5”. To trim use a square acrylic ruler that is the size of your unfinished HST or larger. Place the 45° line of your ruler directly over the diagonal seam of your HST as shown below. Trim just a tiny bit off the right and top edges.

Now turn the HST 180° and again place the 45° line of your ruler directly over the diagonal seam. Line up the sides of the ruler to the previously trimmed edges and trim the HST to 3.5”.

Now all the shapes to make the shoofly block have been cut and made so the block can be assembled. Lay out the pieces on your work surface orienting the HST’s in the correct directions as shown below.

Just for fun you can try orienting the pieces in different ways to see how they look before committing to sewing the block together the shoofly way.

Once you commit to a block design sew the pieces together to form 3 horizontal rows. Press the seams open.

Now sew the rows together being sure to match the seams with pins. There’s a seam matching tutorial in my book Farm & Folk Quilt Alchemy on page 142 and I also shared one in this blog post. Press the seams open. And there we have a 9” shoofly block. You can use the HST formula above to make bigger or smaller HST’s to make this block in whatever size you desire. If for example you wanted to make a 12” finished shoofly block your unfinished squares and HST’s would need to be 4.5”. If you wanted to make a 6” finished shoofly block your unfinished squares and HST’s would need to be 2.5”. Heck, if you wanted to make a big huge 36” finished block your squares and HST’s would need to be 12.5”. You get the idea. There’s freedom in understanding how to make your own blocks!

Some Bigger HST Blocks

The examples of traditional blocks I’ve shared so far in this tutorial are made up of only 2, 3, and 4 horizontal rows but take a look at the following examples of blocks made with 5 and 6 horizontal rows. These blocks contain more pieces but they’re still made from only squares and HST’s. The possibilities are endless!

The two blocks below are the exact same if you take the colors away. This traditional block is called Union Star. By changing the color placements we have totally different looking blocks.

There are so many possibilities to explore and really the only important rule is to have fun and enjoy the process. I hope this tutorial helps you find the confidence you need to begin making blocks on your own. Patterns are nice at times but the simplest math is all it takes to open the door to a whole lotta quilt blocks.