The "Half-Square" Triangle

You love the way the quilt pattern looks in the picture, and you've bought the book and the fabric and are ready to go. The only problem is that the first step in the instructions is to cut 2000 triangles...and you know triangles are a pain because that bias edge stretches all over the place.

There has to be an easier way.

Here are some methods for making half-square triangles that I developed in the late 1980's. They may be different from the methods you find in quilt books today because, quite frankly, they were developed before everybody and her mother decided to write a book.

The "half-square" triangle is called that because, traditionally, you made one by sewing up the diagonal on a square, then cut away half of it to leave you with two triangles sewn into a square. The disadvantage to this is that it leaves you with a pair of triangles that are too small to be used for that pattern. You are, in effect, throwing away a little under half the fabric you bought. In addition, the tip of the square often gets eaten by the feed dogs as you are trying to feed it into the machine.

One solution is to make the square large enough so that both halves can be sewn to be the correct size for your pattern. To do this you must ensure that the seam allowance you add is sufficient for two triangles. You must add 5/8 of an inch to the measurement in order to allow two 1/4 inch seams on the diagonal. Adding 1/2 inch for two 1/4 inch diagonal seams will not give you enough seam allowance.

The only problem with this method is that you have to add allowances to both sides of the square in order to get it large enough for the triangles you want. If your math skills are as bad as mine, you know that the first couple of times you try this you'll have figured something wrong.

The third method is to make half-rectangle triangles. Why is this better? Because if you don't have to feed the corner into the machine, you will sew the seam from the side of the rectangle and have less chance of it getting mauled by the feed dogs. If you want 2" triangles to match your 2" squares, you cut a 2" strip -- there is no extra figuring for the different pieces.

Cut your fabric on-grain and lay two triangle templates down, spaced 5/8" apart to allow for the seam between them. Mark your cutting and sewing lines, and cut your strips into rectangles. Each rectangle should measure 5/8" longer than it is wide. Feed them through the machine in one direction, turn them around, and sew the other seam. Press all stitching lines flat. Then cut between the two stiching lines and open your triangle squares.

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