Technique Tuesday - Setting Blocks on the Diagonal

Today we are introducing a new feature on the blog: Technique Tuesday with Debby Kratovil. We are excited to have Debby sharing some of her favorite piecing tips and tricks with our blog readers, and we know you'll find the information she shares incredibly useful. 

Florabunda Collection

I'm delighted to share with my Benartex visitors a quilt technique that has baffled many of us: How to set blocks on point. What are the magic numbers to cut those pesky side and corner triangles so they not only fit, but there are no bias edges along the outside edges? This is one of the most popular lessons I have ever offered. I begin with the Florabunda collection by Broadway Studios. Pretty, huh?

I wanted a green fabric for the basket handle and applique, so I selected a fabric from an older the Benartex collection called Katie. By the way, I used that Katie collection to make the quilt on the cover of my new book and I called it Katie's Garden. That was easy!

Cover quilt using that awesome Katie Collection

I selected a block from my 2013 desktop quilting calendar

My block inspiration from my 2013 Block a Day calendar

Auditioning fabric for the side and corner triangles

I selected two of the fabrics and auditioned each one against the block. I like the second one better.

I like this better - stronger contrast

 Time to take the plunge and CUT!

Cutting the SIDE triangles from a 15-1/2" square

There are two sizes of triangles to consider. The first one is the side setting triangle (in picture above). We cut a square that is the finished size of the block (10"), MULTIPLIED by 1.414 and then we add 1-1/4" to that number for seams. I have a handy chart at the end of this blog post, so hold on and stop rolling your eyes. This is math talk, not trash talk! Our number is a whopping 15-1/2" square. Each square gives me 4 side triangles (that's all I need for my 4 block quilt).

Cutting the four CORNER triangles from two 8" squares

The formula for cutting the triangles for the four corners of the quilt: finished size (10"), DIVIDED by 1.414, then add 7/8" for seams. Now I'll show you how they look.

Two side triangles sewn on opposite sides of block; Corner triangle at the ready

The blocks are joined into DIAGONAL rows. The side triangles (there are 4) are added to the top left block, and then the single corner triangle. Press seams toward the floral triangles.

When you lay out your pieces as shown in the diagram below, it's easier to see the sewing sequence.

Can you see those last two remaining seams left for me to do?

Three diagonal rows; 2 remaining seams to do

I will sew those last two seams and then press them open to reduce bulk. When you consider setting your blocks on point, it opens up some wonderful setting options.

I will answer a quick question you might have about the seam allowances I quoted above. When a square is cut into FOUR TRIANGLES, you always consider the block size it will work with. And, you always add 1-1/4" to the size of the cut square so that it will fit the block or unit it is to go with. When a square is cut into TWO TRIANGLES, you consider the block size and only add 7/8" for seam allowances so it will fit with the block or unit it is paired with.

Here is my handy, dandy chart with formulas for standard sized blocks.

And I've done the math for most of them; just find the block size!

You can download this chart and print it out; then hang it up in your sewing room!

Setting Blocks on the Diagonal by Debby Kratovil