How to Sew Half-Square Triangles (Method 3 of 6)

The half-square triangle is a basic piece used in many quilt blocks. Very simply, it is a square that is cut in half from corner to corner (diagonally) to create two triangles within one patch.

As amazing as it sounds, there are several ways to sew these units together. Some of these methods increase the accuracy of the resulting patch (for example Methods 2 and 4). Other methods increase the speed or convenience of sewing many half-square triangles (Methods 5 and 6).

Which method you use depends upon personal preference.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Fabric
• Thread
• Rotary Mat or Scissors
• Sewing Machine or Needle
• Fabric Marker

1. 

   This method calls for cutting squares, sewing the seams for the triangles, and then cutting the triangles apart. Sewing the pieces as squares adds stability, and you will be less likely to stretch the fabric. It may add some time to your sewing, since there is extra marking. It may be a good trade off for the increased accuracy.
   
   Cut your fabric into squares. To determine the cut size, take the finished size and add ⅞” to both sides. For example, if you are using 2” squares (finished size), cut 2⅞” squares, just as in the above step.

2. 

   Place the squares right sides together, and mark a cutting line from corner to corner (diagonally across the square). Next, mark two sewing lines – one on each side of the cutting line ¼” away from the cutting line.

3. 

   Stitch on both of the sewing lines.

4. 

   Cut between the sewing lines on the cutting line you marked.

5. 

   Open each half-square triangle, and press (preferable press the seam allowance so it is under the darker fabric).

6. Trim the “dog ears” off of the edges of the squares.

Resources

• How to Quilt
• Quilt Block Library