Showing posts with label math for quilters. Show all posts
Showing posts with label math for quilters. Show all posts

Sunday, January 19, 2025

CHANGE THE SIZE OF YOUR QUILT

 I am often asked for help by a quilter wanting to change the size of a quilt pattern. Perhaps it's too big. Perhaps it's too small. How do you increase or decrease a quilt to be size you want?

Let's look at Laurel Ridge, the 2025 Block of the Month quilt designed by Lynn Wilder exclusively for THE QUILT SHOW. As designed the quilt is 90" square:

For some people, this is too large and they want to make it smaller. How do you convert a pattern from LARGE to SMALL?

1. Make the blocks smaller: this works with larger blocks, say 10" or larger, but these blocks are only 5". Making them 2.5" finished would be quite a challenge. 

2. Make fewer blocks. Because this quilt is a Medallion-style, it makes sense to keep the middle the same and work out until the quilt is the size you want. 

I played around with EQ8 for some possibilities. The middle would remain the same as the original pattern. I didn't draw it, you can imagine it there. This quilt is 52" square with a 1" border on the outside. It can easily be enlarged with more or wider borders:

More borders, now it's 62" square:

Let's add another row of blocks. The blank spaces are for the applique yet to come. I am replacing those blocks with pieced blocks so will save that REVEAL for a few more weeks. It is 62" square now, an outer border would easily enlarge it:


What if you don't want a square quilt? Add additional borders on the top and bottom to lengthen it. Now it's 74" x 80":


Your first decision should be the finished size of the quilt. Once that is set, more or less, play with a variety of options until you say "Aha! That's just what I want"!

Here is one more example. For many years I planned to make this quilt, designed and made by Catherine Butterworth, who lives in Australia:


I called it "Diamond Jubilee" and expected to have it done by MY Diamond Jubilee--my 60th birthday. That was more than 10 years ago and here is what I have today:


It may get a little bigger, and a pieced border is definitely in the plan:


None of this is set in stone just yet. Why did it get smaller? I no longer need another King or Queen size quilt. This has been incubating for so MANY years it is just time to get it done. While I still love Catherine's original, my blocks just aren't speaking to me any more. So my current plan is to have three more Feathered Star blocks, then decide on block placement, sashing color, pieced borders--style and colors--and then get this one DONE in 2025. Finished is better than perfect.

If you have a pattern you like, don't be afraid to "tweak" it a bit to make it your own. Always be sure to credit the original designer on the label--you DO PUT A LABEL on ALL YOUR QUILTS, RIGHT??!!

I am a stickler for LABELS:  here is my TUTORIAL: QUILT LABELS--DON'T LEAVE HOME WITHOUT THEM  

Let's quilt.

Barbara


Wednesday, August 19, 2020

Simple Math for Quilters

I have been teaching quiltmaking for more than 30 years. It quickly became apparent that some quilters were petrified of "math" and didn't think they could make quilts if they had to use math skills. As long as they have a pattern with all sizes explained, they are happy. And that is perfectly OK.

For me, and those like me, it is just the opposite--math skills make it easier for us to make quilts, in the sizes we want to make them. We use our calculators to figure out what sizes to cut our pieces. This gives us freedom to design our quilts as we choose.

Student work: made in a 5 Easy Pieces Workshop I taught in Panama City, FL--isn't this beautiful? It has half square and quarter square triangles, and squares. Once you know the "magic numbers for quilters" you can make anything: 


I always tell beginning students: "if you had known you were going to be a quilter, you would have paid more attention in Geometry class". What we do is pretty much basic geometry--shapes and sizes--all determined by the basic "rules" of geometry.

Rotary Cutting Changed Everything--we used to cut templates from cardboard or plastic, and trace around them. Now, we cut with a Rotary cutter and rulers, getting the pieces quickly cut the exact size we need, usually for machine piecing.

So, let's just look at a few of the Basic Magic Numbers Every Quilter Needs to Know:

1. We need to know the FINISHED size of the piece we need to cut--that is the size it will be AFTER it is sewn into the quilt. 

2. SQUARES and RECTANGLES: add 1/2" to the finished size--2" finished square would be cut 2.5",    2" X 4" finished rectangle would be cut 2.5" x 4.5" 

3. HALF SQUARE TRIANGLES: add 7/8" to the finished size, cut in half ONCE on the diagonal--you may choose to add 1" to create a bit of insurance--you will have to "trim to size" when sewn. The "trim to" size is simply 1/2" larger than the Finished size--just like ALL squares and rectangles.

4. QUARTER SQUARE TRIANGLES: add 1.25" to the finished size, cut in half TWICE on BOTH diagonals. These can also be over-sized--add 1.5" to finished size to oversize. Then "trim to" 1/2" larger than the finished size--it is a square and that is still the rule, just like Half Square triangle squares and plain squares. 

Let's Practice with this simple project, a little table topper, about 17" square:

The Shoo-Fly blocks are 6" finished so the floral print square in the middle is cut 6.5" I like to make HST with a HST ruler--see how to make this block here: Shoo Fly blocks

The Perimeter Triangles are Quarter Square triangles--we want the LONG side of the triangle, which is along the outside edge, to be straight of grain. We need to do a bit more math. 

We know the SHORT side of the quarter square triangle finishes at 6"--it is sewn to the 6" Shoo Fly Blocks. To figure out the length of the LONG side, MULTIPLE 6" x 1.4142 (another magic number, the square root of 2"--don't worry, there will not be a test at the end). 

6" x 1.4142 = 8.4852" --that is pretty darn close to 8.5" so we will use 8.5" as the FINISHED size of the LONG side of the QST. 

From the Magic Numbers above, we now add 1.25" to 8.5" = 9.75" to know what size square to cut that will give you 4 QST the correct size. I like my blocks to "float" just a bit so I cut the square 10":



Now let's figure out what size squares we need for the four corner triangles--they are HST--we want the straight of grain on the SHORT sides of the triangles.

We know the LONG side of the HST will measure 6" finished--it is sewn to the 6" Shoo Fly blocks. To figure out the short side measurement, DIVIDE 6" by 1.4142.

6" / 1.4142 = 4.24268"--that's pretty darn close to 4.25" so we use 4.25" as the FINISHED size of the SHORT side of the HST. 

From the Magic Numbers above, we now add .875" to 4.25" = 5.125" to know what size squares to cut to get the 4 HST needed for the four corners. Again, I like that "float" so I cut two squares 5.5", then cut them in half once on the diagonal. I can always trim them down if I like once the top is sewn.. You could use 5.25" for less "float", you decide.


I designed a sew-a-long a few years back to practice using these numbers. All 5 posts are still there, an a excellent step-by-step project with lots of photos. How to Make a Quilt in 5 Easy Steps

There are more advanced "magic numbers" for more unusual shapes but let's save those for another day.

Let's quilt.

Barbara