We’ve dealt with borders for the past few blogs, and most of the quilts that we looked at while discussing all our border options were horizontal-set quilts – that is the quilts were made of blocks, all lined up in rows both horizontally and vertically. However, now I want you to think about changing the quilt top up a little bit – not with anymore borders, but with putting the quilt blocks on-point.
What does on-point mean? It means that instead of horizontally setting the block, it’s turned and is set in the quilt with the corners in a vertical and horizontal position instead of a horizontal position. So, instead of this:
Which means, instead of the quilt looking like this:
It could look like this:
This on-point option is a very simple one, and like most quilt design options, the quilter is only limited by his or her imagination. I want to discuss the options, so that you can let your imagination run wild, but first I want to walk you through the basic steps of how you construct an on-point quilt.
Let’s say you have a wonderful idea for a quilt, or you have a great pattern, but for some reason you just aren’t diggin’ the whole horizontal and vertical row thing. I can understand that. While I’m not opposed to that layout (indeed, some quilts will not work unless they’re laid out that way), I do love me an on-point quilt. There’s more movement in it and there are just so many options available.
But how do you go about making that change?
It’s not hard, I promise…but just like borders, you have to do the math. So, let’s take this process from the top.
Let’s say you have a stack of 12 ½-inch unfinished squares and you decide to put them on-point in a quilt top.
Notice that there are spaces for your blocks as well as spaces for triangles. These triangles are called setting triangles and they look far more complicated than they are. In this layout there are two sizes of triangles. Along the sides are larger triangles and at the top and bottom right- and left-hand sides are smaller triangles called corner triangles. The plain blocks that fit in between your pieced blocks are the same size. That’s not hard to figure out. But what about those triangles? How do you figure out how big to make them? And do you cut them out as triangles or is there someway you can cut out a square and then sub-cut it into triangles?
The answer to the first question is there is a math equation you can use and the answer to the second question is yes! Let’s start at the beginning, working with the above layout.
First let’s play with your blocks, and for the sake of this example, let’s say you’ve got nine 9-patch blocks that are 12 ½-inch unfinished.
That means the plain squares set between the 9-patch blocks will also need to cut 12 ½-inches, unfinished.
But what about the triangles?
There are couple of important details to remember about triangles before we begin the math. First, one or more edges of nearly all triangles will be cut on the bias; therefore, handle them cautiously and be careful not to stretch the bias. The large triangles in an on-point quilt will be quarter-square triangles – that is, we cut four of these triangles from one square of fabric – and it’s important that the long edge of these triangles (called the base) is cut on the straight-of-grain of the fabric. If the base is cut on the bias, you’re going to run into all kinds of problems—it will stretch, and you’ll never get the quilt to lay flat.
The smaller triangles at the right and left corners, top and bottom, are half-square triangles – they are produced by cutting out a square and then sub-cutting that square on the diagonal. These must have their short-sides on the straight-of-grain.
If you’re thinking ahead, you’ve been hit with a couple of facts that maybe causing you some concern at this point:
- The blocks are 12 ½-inches unfinished.
- When the blocks are set in the quilt, the blocks will be 12-inches, finished.
- In order to cut the large triangles, we need to know the long measurement, but we only know the short (12 inches).
- In order to cut the small triangles, we need to know the short measurement, but only know the long (12 inches).
What’s a quilter to do?
Learn a new formula, that’s what.
I introduced you to the Golden Ratio (1.618) in my blogs about borders. Let me now introduce to what is called Quilter’s Cake (mathematicians have pi, we have cake…) 1.414.
For the large, setting triangles –
Step One: Take the finished size of the block and multiply it by 1.414
12 x 1.414 = 16.968 round this up to 17.
Step Two: Add 1 ¼-inches for seams.
17 + 1 ¼ = 18 ¼
Thus, an 18 ¼ – inch square will produce four of the large triangles you will need for the above quilt (shown in coral color in the illustration). There are eight large triangles, you get four triangles per square, so you would only need to cut two 18 ¼-inch squares and then sub-cut those by cutting them twice on the diagonals.
Now let’s talk about the small corner triangles, which are colored green in this illustration:
There are four of those, and since these are half-square triangles, we know we only need to cut two squares, but we need to know what size to cut them.
For the small corner triangles –
Step One: Take the finished size of the block and divide it by 1.414.
12 ÷ 1.414 = 8.4865629. Round this up to 8 ½ -inches.
Step Two: This time add 7/8-inch for seams.
8 ½ + 7/8 = 9 3/8-inches
Cut two 9 3/8-inch squares and cut them in half on the diagonal one time. Each on-point quilt always has four corners (well…all quilts have four corners), so you always need only four small corner triangles.
Chew on all this information during the week. Next week we’re going to let our imaginations go crazy with those setting triangles and blocks.
Until next week, Quilt with Excellence!
Love and Stitches
Sherri and Sam