On-point quilts with zero math? Learn how (+ giveaway!)

Quilt patterns from On-Point Patchwork
Quilts from
On-Point Patchwork by Donna Lynn Thomas

Ever passed on a pattern because of on-point units, blocks, or borders? If there’s a math-related puzzle that’s plagued quilters since quilting began, it’s how to set quilt blocks on point. Perhaps you’ve heard of the quilter’s magic number: 1.414 (more on that number here). If you want to design quilts on point, that magic number works great for figuring dimensions for diagonal quilt patterns. But trying to slice fabric to 1/16 or 1/32 of an inch isn’t easy with a rotary cutter. Cutting gets fudged. Pieces get tugged. As a result, sewing gets less and less precise—while the expletives grow surprisingly on point!

On-Point PatchworkTen-time author and self-proclaimed math geek Donna Lynn Thomas recently completed what most of us would consider a daunting mission: to find out how to set quilt blocks on point—precisely—with rotary equipment alone. Her new book On-Point Patchwork and her new Omnigrid On-Point Ruler help you create on-point quilts with no templates and no math—just a swish of your blade. Today Donna is here to dish about the inspiration behind her latest book, and to offer a peek into what it’s like to design quilts with the help of a mathematician’s mind. She may call herself a math geek, but we’re calling her the Patchwork Professor. Thanks for being here, Donna!


Donna Lynn ThomasGeek alert! Yes, I am one of those rare birds who loves math and geometry. I was also one of those annoying students who used to ask for more proofs and theorems for homework—hey, they were fun! You can see my love of geometry translated into the 14 quilts in On-Point Patchwork. I love piecing and complex-looking design, although that doesn’t necessarily mean I love complex construction. I’m not totally crazy.

I also love browsing through Barbara Brackman’s Encyclopedia of Pieced Quilt Patterns. I like playing with the cool old designs, making changes here and there, but many of these blocks have plain or pieced components that are set on point inside the blocks. Since mainstream quiltmaking has switched from homemade templates to rotary cutting, we don’t make a lot of those old patterns anymore. I’ll explain why in just a bit.

Variable Star blockHere’s a beautiful variation of the Variable Star block (left) from one of the quilts in On-Point Patchwork. How would you go about strip piecing and making the nine-patch units in the center of this block with a rotary cutter and ruler? Regular rotary rulers cut pieces to measure evenly from side to side. With on-point units, such as this nine patch, the pieces must measure evenly on the diagonal, not side to side, because the diagonal measurement is the one parallel to the edge of the block. In this case, each nine-patch square must measure 2″ diagonally if it is to fit inside the 6″ block center.

You can calculate the diagonal of a square, but in most cases it results in measurements of 1/16 or 1/32 of an inch. As much as I love numbers, I don’t love measuring 16ths of an inch accurately with a rotary-cutting ruler. That’s just setting me up for a day of easing, stretching, or fudging when I assemble on-point blocks and borders. Who wants to do that—or the math?

Back in the dark ages when templates roamed the earth, we made any shape we wanted in absolutely any size. If you could draw it, no matter what size or dimension, you could make a template. We weren’t restricted to side-to-side measurements like we are with rotary cutting.

It dawned on me that we needed a ruler that could cut shapes that measured differently than regular rulers. In addition to side-to-side measurements, we needed even diagonals. Enter the Omnigrid On-Point Ruler.

Omnigrid On-Point Ruler

Let’s go back to the Variable Star block above. We want those squares to measure 2″ on the diagonal. Easy!

1. Cut strips using the 2″ mark on the On-Point Ruler.

2. Cut the strips into squares at the 2″ mark. When sewn in place, the squares will finish to 2″ on the diagonal.

You don’t even have to add ½" for seams—that’s built into the ½" clear margin on the edge of the ruler. In a nutshell, the desired diagonal measurement is equal to the ruler cutting mark. It’s that simple!

Using the On-Point Ruler

Or better yet, sew strips sets for the nine patch instead of cutting individual squares. Cut the segments using the 2″ mark. Make your nine patch like always.

Cutting strip sets with the On-Point Ruler

I was so excited about the possibilities for the ruler that I knew I had to write a book full of all the things you could do with it. Besides squares, we can now make rectangles and half-square-triangle units that measure correctly when set on point. But most of all, I wanted quilters to be able to use the On-Point Ruler to design their own blocks, borders, and quilts with on-point patchwork.

In this video, I offer a more in-depth explanation of the ruler.


View Donna’s video "How to set quilt blocks on point (no templates, no math!)" on YouTube

See if you can find the on-point patchwork in these quilts:

Split Geese quilt
“Split Geese”

High Rise quilt
“High Rise”

Pinwheels in the Park quilt
“Pinwheels in the Park”

Make Me Smile quilt
“Make Me Smile”

Boxes and Bows quilt
“Boxes and Bows”

Batik Feathers quilt
“Batik Feathers”

I can’t wait to see what you make. I know MY mind just keeps racing with ideas for new blocks and quilts. Where’s my sketch pad…


Donna, thanks for showing us that math wizardry isn’t required to make on-point quilts!

You can find Donna online at donnalynnthomas.com.

How’s your quilt math—A+, average, or completely absent? Share your score in the comments and you’ll be entered to win a copy of On-Point Patchwork and the Omnigrid On-Point Ruler! We’ll choose a random winner one week from today and let you know by email if you win.

Comments are closed for this post.

Thanks to all who entered the drawing! The randomly chosen winner is Ele, who writes:

“My math ability has gone on an extended vacation and I’m not sure if it will ever come back. I love quilting books and I love quilting tools, and I have a lot of both, but another of each never hurts.  Would love to win the book so I can use some of those luscious patterns. Thanks for the effort to come up with the book and the ruler.”

Ele, we’ll email you about your prize. Congratulations!


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