There are three patchwork squares used repeatedly in quilt tops: the half-square triangle unit, the quarter-square triangle unit, and the four-patch. Since quilting has been around for some time, quick and accurate methods for constructing these squares have been introduced into the quilting community. Additionally, I have recently developed a method for making four-patches that I really like and that produces consistently accurate results every time. It just came to me while piecing one day, but it’s hard to believe some other quilter hasn’t thought of it before (and they probably have; I just haven’t seen it anywhere.)
This tutorial will introduce the half-square triangle unit. I will be making two units at the same time, but you can make a single unit just as easily. Each of the squares mentioned above have a special measurement to remember. Don’t worry, it’s simple math.
To begin, choose two fabrics, one light and one dark. Think about the size you want your finished (sewn) square. To that measurement, add 7/8-inch. That is always the case regardless of your finished measurement. For example, if I wanted my finished squares to be six inches, I would cut my light and dark squares 6 7/8-inches.
I would like to give you a quick tip at this point. For greater accuracy, starch your fabric. By its very nature, fabric shifts while being sewn. Starching your fabric prevents some of the shifting and stretching, which makes for happy quilting. I use Sta-Flo liquid starch and mix it 50-50 with distilled water. I then pour it into a spray bottle that I always keep by my iron.
Starch Your Fabric
Here is one more tip. I quickly cut my squares a little larger than the desired measurement and then starch them. Sometimes the fabric shrinks slightly, so this insures that I won’t have any problems getting the exact cut I need. After pressing the starched squares, I then cut the precise measurement.
Now you have two accurately cut squares that are 7/8-inches larger than your finished square measurement. In my case, I have doubled the measurement (width) so that I will have two finished units in the end.
Turn the light square over (face down) and place it on top of the dark square. With a sharp pencil in hand, position your ruler diagonally, crossing the top left and bottom right corner of the square units. Draw a line from corner to corner on the wrong side of the square.
If you are making a double unit, draw a line down the center. Then position your ruler diagonally as above and draw a pencil line from corner to corner. Repeat for the second unit.
Center Line for Double Unit
Diagonal Cutting Lines
If you don’t have a patchwork presser foot, mark ¼-inch sewing lines on each side of the solid lines. I would recommend dashed lines so that you can distinguish sewing lines from cutting lines.
Take your marked square (or rectangle) to the machine and place a few strategic pins here and there to keep the fabric in place. Attach a patchwork presser foot (quarter-inch foot) or sew the ¼-inch dashed lines that you marked. Begin sewing a scant ¼-inch from the solid pencil line.
Sewing 1/4-inch from Cutting Line
When you finish sewing one side, lift the presser foot and reposition the unit so that you can sew down the other side of the marked line. If you are working on a double unit, continue sewing until you have sewn scant ¼-inch seams on both sides of your solid pencil line.
Turning the Corner
Take your ruler and place it on the solid pencil line between your stitching lines. Using a rotary cutter, cut the unit(s) in half.
For the double unit, cut the center line first, then proceed to cut the units in half.
Cutting the Center Line
Cutting the Diagonal Lines
Now open your units and press toward the dark fabric. Square them if necessary, checking your measurements to make sure they are precise.
If you have made several units, you can play with them to make various patterns. Here I have made a pin wheel. Wasn’t that easy?
In the next tutorial, I will show you how to create quarter-square triangle units. The method will build on what you have learned in this lesson. Happy quilting!
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