When you're making more than one Half Square Triangle (HST) it is faster to make them in multiple units. I find the methods below let you sew without dealing with the bias of using 2 triangles. Generally you're using a dark and light fabric. Instead of cutting them one at a time, I like to place my fabric right sides together and then cut the 2 squares at once. Then they're all ready to go. Below are instructions for making 2 at a time and 8 at a time. I've given you the formula so that you can make what ever size you might need. The examples are for a finished 2" unit.
For you beginners, there are two terms, "finished" and "unfinished". "Finished" is the size of the unit and/or block once it's sewn into a block or quilt. "Unfinished" is the size of the unit and/or block with the seam allowance added on. For a 2" finished block, you'd cut 2 1/2". For HST, you need to add more than just the 1/4" seam allowance on each side.
Most instructions have you add 7/8" rather than the 1" I've given you. I have yet to get both (or all 8) of my HST to come out exactly. By adding a full inch, I can trim them to the exact size needed. That being said, I still sew with a scant 1/4" seam.
In a previous post about my "favorite things", I mentioned the "Loc-Bloc" ruler from trimming HST. If you don't have one here is how you trim your HST: It is MOST IMPORTANT that you place the diagonal line of your square ruler on the diagonal seam. Adjust it up or down the seam to make sure you can see that the fabric extends past the parameters of the size you want to cut. Your seam should be exactly at the corners of your square.
Two Half Square Triangles
Formula: Size of finished Half Square Triangle plus 1"
Example: 2" finished block + 1" = 3" square
(3" finished block + 1" = 4" square)
Place the two fabrics right sides together
Cut a 3" square (1 of each color)
Draw a single diagonal line (Fig. 1)
Stitch 1/4" on both sides of lines (Fig.2)
Press stitched piece before cutting apart
Cut between stitching on drawn line (Fig. 3)
Press both Half Square Triangles toward the dark fabric (Fig. 4)
Trim each to a 2 1/2" square
Eight Half Square Triangles
Formula: Size of finished Half Square Triangle plus 1"times 2
Example: 2" finished block + 1" = 3" X 2 = 6" square
( 3" finished block + 1" = 4" X 2 = 8" square)
Place the two fabrics right sides together
Cut 6" square (1 of each color)
Draw a diagonal line in both directions on the lighter fabric (Fig. 5)
Stitch 1/4" on both sides of both lines (dotted lines are stitching lines) (Fig. 6)
Press stitched piece before cutting apart
Cut piece in half horizontally and vertically, then cut diagonally between stitches on drawn lines (Fig. 7)
Press the 8 Half Square Triangles toward dark fabric
Trim each to a 2 1/2" square.
