"Quarter-Square Triangles"
Many patchwork patterns involve the use of triangles, which enables the creation of hundreds of interesting and inovative designs.
All triangles have three sides and three angles but the length of the sides and the degree of each angle can vary, allowing an infinite number of triangular shapes. This makes working with triangles very exciting but also, quite tricky, if you don't know a few essential quilting tips.
No matter how you cut a triangle, you will always end up with at least one edge of the triangle being cut along the fabric bias. (The true bias runs at a 45-degree angle to the straight grain of the fabric but any cut that doesn't run directly along the straight grain is considered to be a bias cut.) The bias is very stretchy and as such is difficult to sew accurately.
In order to ensure your quilt sits flat and has accurately sewn seams, it is particularly important that you avoid placing any bias cut onto the outer edges of your quilt blocks.
The two most common regular triangles used in quilting are:
This lesson covers all you need to know about working with quarter-square triangles. I've compiled a few tips to help you make perfect quarter-square triangles quickly, simply and totally trouble free.
Read on and you'll learn:
- What a "quarter-square triangle" is!
- How to make individual quarter-square triangle units.
- Quick-piecing methods to avoid handling the stretchy bias edges.
- How to make multiple "quarter-square" triangle units using grid methods.
- How to "calculate" the size of your cut squares in order to make accurate quarter-square triangle units.
So, lets get started...
WHAT IS A QUARTER-SQUARE TRIANGLE???
Very simply, a quarter square triangle is one fourth or a quarter of a square!
Although quarter-square triangles look just like half-square triangles, they're really very different. With a half-square triangle the longest edge is a "bias" edge. However, the "straight grain" runs along the longest edge of a quarter square triangle.
Quarter-square triangles are used in some block patterns including: Ohio Star and Card Trick, but most often they are used as setting triangles. When a quilt is set "on point", quarter triangles are used to fill in the triangular spaces along the edges of the quilt.
Using quarter-square triangles ensures that the straight grain edges run along the perimeter of the quilt. Using half-square triangles in this situation would mean that the stretchy bias edges would be on the perimeter of the quilt and may result in your quilt not sitting flat.
REMEMBER: It is most important to maintain the straight grain on the outside edges of each of your blocks and even more so on the outer edge of your quilt.
Where possible it is best to create "quick-pieced" quarter square triangles but there are times when it's necessary to cut individual patches.
A quarter-square triangle is created by cutting a square diagonally in half and then in half again!
By sewing four quarter-square triangles together you form a quarter-square triangle unit. Two or more contrasting colors can be used in these units to create different and unique designs, especially when several units are sewn together to form a block.
A Quarter-Square Triangle Unit
The correct construction of quarter-square triangle units it "very important" because it is essential to keep the straight grain of your fabric on the outside edges of each of your blocks. This helps to maintain accuracy in your piecing by avoiding the stitching of the stretchy bias edges.
HOW TO MAKE QUARTER-SQUARE TRIANGLE UNITS
This method involves cutting the fabric triangles first and then sewing them together. It is ideal if you only need a few half-square triangle units.
- Cut squares from two contrasting (light and dark) fabrics or more as your pattern requires.
- With your rotary cutter and ruler, slice each square from corner to corner along both diagonals to make four triangles of each color.
- Pair up light and dark triangles of fabric. Place the light and dark fabric with right sides together and edges matching. It is important to place each set of triangles with the same fabric on the top and always start stitching from the straight edge. Remember to handle very carefully to avoid stretching the bias.
- Sew along one of the short bias edges. Stitch a 1/4" seam along the long edge. It is important to use a 1/4" foot for accuracy. Repeat with the other sets of triangles. Note: Arrow shows straight grain of fabric.
- Finger-press the pieced triangles open with the seam allowance placed towards the darker of the two fabrics, then carefully press each unit open with a hot iron.
- Next, take two of the now half-square triangle units and place them with right sides together. Butt the centre seams closely together. If you have pressed correctly, the seam allowances should be facing opposite directions allowing the seams to sit "snug" and flat.
- Again, finger-press the pieced squares open with the seam allowance placed towards one side, then carefully press each unit open with a hot iron.
- Trim the fabric points so you have a neatly finished square.
- You will end up with two identical half-square triangle units for each pair of squares you cut and sew.
- The straight grain of each triangle will run along the outer edges of the square unit as shown by the arrows.
- Some block designs may require fabric units that have both half-square and quarter-square triangles like the one below.
- This block is composed of three triangles. The larger triangle is a half square triangle. The two smaller triangles are two units from a quarter-square triangle block. You will need to use formulas from both the half-square and quarter-square triangle lessons to create these blocks.
Sewing individual triangles together as the method above describes, is both fiddly and frustrating! Once you cut the fabric along the bias, as you do when cutting triangles from a square, the bias edge stretches easily, making it difficult to sew accurately.
But do not despair -- help is at hand!
As with half-square triangles, there are some "quick-piecing methods" that help you to make quarter-square triangles much more quickly and without handling the bias edge.
Click here to learn about...
"Quick-Piecing Quarter-Square Triangle Methods"
I hope you've found this information on "quarter-square triangles" useful.
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