September 20, 2006

December 12, 2001

On-Point Setting Triangles Tutorial

A quilt that has each block set on the diagonal is called an "on-point" setting. It has a tendency to intimidate quilters for one simple reason: The triangles around the edge!

This tutorial is designed to take the mystery out of making all of the triangles needed for an on-point setting and also to demonstrate that things that look too complicated to do, aren't necessarily.

Don't let the "look" of this tutorial scare you! If you read through it once, and follow the examples, you should have no problem understanding the concept. And if you dislike doing the math, watch for the calculator icon and use the calculators provided: Diagonal Calculator, Square Calculator.

The quilt diagram pictured above illustrates a typical on-point quilt, with the blue and white squares representing the blocks. The blue blocks are the "Outside" blocks and the white blocks are the "Inside" blocks. The pink triangles are called "Edge" triangles and the purple triangles are called "Corner" triangles. The number of Edge triangles can vary from one quilt to another, but there are always four Corner triangles. In this sample, there are eight Edge triangles.

Since math isn't everyone's favorite subject, and since there are a lot of fractional measurements involved in diagonal settings, it is recommended that you keep a calculator nearby. If you don't have a calculator, use the one provided with any computer running Windows, by clicking Start/Programs/Accessories/Calculator.

Getting Started

Normally, the measurement that is important in sewing a quilt top together is the width of the block. However, in a diagonally set quilt, the most important measurement is the diagonal measurement, measuring from one corner to its opposite corner.

There are three different methods of measuring the diagonal measurement:

Simply measure from one corner to the opposite corner. This will more than likely be an odd measurement (fractional), so round it up to the nearest 1/8". Refer to the Fractional Measurements Table below for conversions. For example, the fractions 4/16", 2/8", and 1/4" are all equal in measurement. Their decimal equivalent is .25.

Fractional Measurements Conversion Table

1/16"

2/16"

3/16"

4/16"

5/16"

6/16"

7/16"

8/16"

9/16"

10/16"

11/16"

12/16"

13/16"

14/16"

15/16"

16/16"

1/8"

2/8"

3/8"

4/8"

5/8"

6/8"

7/8"

8/8"

1/4"

2/4"

3/4"

4/4"

1/2"

2/2"

.0625

.125

.1875

.25

.3125

.375

.4375

.5625

.625

.6875

.75

.8125

.875

.9375

1.000

If you know the finished size of the block, simply multiply it by 1.414 and round up to the nearest 1/8". For example, if the finished size of a block is 12", then multiply that by 1.414 to get 16.968, which would round up to 17". So, a 12" block has a diagonal measurement of 17". A 9" finished block would be 12 3/4" diagonally (9 x 1.414 = 12.726, which rounds to 12.75 which is 12 3/4").
Use the calculator!
Worksheet: My quilt's finished block size is _________ with a diagonal measurement of _______.

Lay out the quilt blocks in the way that you want them sewn, leaving the edges and corners empty (which we'll fill as we continue).

Play with the design until you have a layout that is pleasing to you. Once you begin sewing these together, it's difficult to rearrange!

Making the Edge Triangles

One fact that we need to keep utmost in mind is that the bias edges of triangles should NEVER go along the outside edge of quilt. Never.

Referring to the quilt diagram above, the pink triangles are the Edge triangles. These triangles are made by cutting a large square diagonally, twice, in the form of an "x". Once cut in this manner, it makes four triangles from the one square, with the base (the longest side) of the triangle being on the outer edge (straight of grain) and NOT on the bias.

Follow these simple steps to make the Edge triangles for your quilt:

Count the number of Edge triangles needed for your quilt. Divide this number by 4 (because for each square we cut, it yields 4 triangles). For example, the above quilt has 8 Edge triangles, so 8 divided by 4 is equal to 2. Therefore, we need to cut 2 large squares, the size to be determined in the next step. If you have a number of Edge triangles that won't divide by 4 equally, then round up. For example, if your quilt has only 6 Edge triangles, 6 divided by 4 is equal to 1.5, rounded up to 2 (because you can't cut 1.5 squares!).
Worksheet: My quilt needs _______ Edge triangles, which would mean I need _____ large squares.

To determine the size of the large squares to cut, you can either use the calculator provided, or do the math yourself using the diagonal measurement that you arrived at in the Getting Started section above (and wrote down in step 4). Using this measurement, add a minimum of 1 1/2". For example, if the diagonal measurement was 17", then add 1 1/2" to 17" to get the large square size of 18 1/2". You would cut your large squares to this measurement.

Cut the squares a little larger than the minimum of 1 1/2". I usually cut my squares at least 2" larger, rather than the 1 1/2". Why? It's much easier to trim the excess fabric than it is to try to glue fabric on the quilt top if you run short!

Worksheet: I need to cut _____ large squares that are ______ big.
Once the correct number of large squares are cut to the large size, cut them diagonally, twice. This makes 4 triangles for each large square.
Place these Edge triangles in the quilt layout, making sure that the base (long side) of the triangle is on the outer edge of the quilt.

Making the Corner Triangles

Every on-point quilt requires four corner triangles, shown in purple in the quilt illustrated at the top.

One fact should be repeated: We need to keep utmost in mind that the bias edges of triangles should NEVER go along the outside edge of quilt. Never.

Follow these simple steps to make the Corner triangles for your quilt:

You are going to need 2 large squares to make the Corner triangles. Each of these squares is going to be cut once on the diagonal, to yield 2 triangles per square.

To determine the size of the 2 large squares, do these two things: First, multiply the finished block size by 0.707, then round the result up to the nearest 1/8" and second, add 1" to the new measurement. For example, if the finished block is 12", then first multiply that by 0.707. This equals 8.484. Round this up to 8.5. Second, using this new measurement of 8.5, add 1". This now equals 9.5". Another example, if the finished block is 9", then multiply by 0.707, then add 1". So, 9 x 0.707 = 6.363. Round this up to 6.5". Add 1" to get a measurement of 7.5". Calculator for this coming soon!

Cut the squares a little larger than the calculated measurement of the large square. I usually cut my squares at least 1" larger. Why? It's much easier to trim the excess fabric than it is to try to glue fabric on the quilt top if you run short!

Worksheet: My finished block size is ______, multiplied by 0.707 equals ______, rounded up to _____. Add 1" and my large block size to cut is ______.
Worksheet: I need to cut 2 large squares ________ big.
Once the 2 large squares are cut to the large size, cut them diagonally, once. This makes 2 triangles for each large square, for a total of 4 Corner triangles. Notice that the base (long side) of the triangles cut once from a square are on the BIAS, not on the straight of grain. Just the opposite of the Edge triangles.
Place these Corner triangles in the quilt layout, making sure that the base (long side) of the triangle is on the inside edge of the quilt this time.

Options!

There are several options available that can totally change the look of your quilt. Here are a few:

Use a different block as the Inside block.
Use a plain block (one piece of fabric) for the Inside blocks.
Use a different color for the Inside blocks.
Use a different color for the Edge and Corner triangles.
Use a directional fabric for the Inside, Edge, and/or Corner. Be sure to keep the direction going in the same way! This could require extra cutting.
Take one last look at your arrangement. If you aren't happy with it, this is the time to change it!

Assembly!

Assembly begins in the top left corner and moves downward to the bottom right.

Follow these simple instructions for assembling the on-point quilt top:

Leaving the top left corner triangle alone, begin by picking up the first two items in the second diagonal row, which are an Edge triangle and a block. Do not sew the Corner triangles on until step 7. Refer to the image below that illustrates the first two items (an Edge triangle and a block), each marked with a large 'X'.
Place the Edge triangle right sides together with the block (so that the Edge triangle is on bottom), matching the right angle corner to the corner of the block. Sew these two pieces together, using a scant (just short) 1/4" seam.
Place them back in the diagonal row to check for accuracy and make sure that they are in the correct position.
Pick up the next block or Edge and following the same method, sew it to the first unit sewn in step 2. In the sample quilt illustrated above, an Edge would be sewn to a block, then finished with the other Edge. There are only 3 items to sew together in the second diagonal row in the sample quilt.

Sew each of the diagonal rows together using the same method. Refer to the diagram below for a suggested order of sewing, beginning with 1.

It is important to continue laying sewn pieces back onto the layout and checking for accuracy and correct position. Skipping this step to save time can cost you later. Voice of experience here!

Press the seam allowances in each diagonal row toward the Inside blocks or toward the Edge triangles, then pin the rows together, using the pressed seams to "snug" together and match intersecting points. Sew the diagonal rows together using a scant 1/4" seam. Row 1-2-3 is sewn to 4-5-6-7-8, then this unit is sewn to 9-10-11-12-13, etc.
Once all the diagonal rows are sewn together, it's time to add the Corner triangles. First, it's important to find the center of the base (long side) of the Corner triangles. To do this, simply fold the Corner triangle in half, along the base. Finger press the fold near the base edge, or use a pin to mark the center.
Locate the center of the side of the block that you are going to sew the Corner triangle to. Mark the center with a pin or finger press.
Place the Corner triangle right sides together with the block, being careful to match the centers of each.
Pin the two pieces together, first in the middle, then at each end. Sew with the Corner triangle on the bottom.
Press the quilt top flat, then trim the sides even, being very careful to leave a precise 1/4" from the intersections of where the triangles and blocks are sewn.
Add borders, if desired.
Layer with batting and the backing, quilt, then bind.

This concludes the tutorial. I hope that it was easy to follow and understand and that you now have a better understanding of setting quilt tops on-point. Should you have any questions, or comments, please e-mail me.

Here is a sample of a quilt top that I finished with an on-point setting.

Good luck, happy quilting, and have fun!

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