Believe it or not, cutting half-square triangles with templates and chain piecing is faster, and more accurate, than other methods, like sewing 2 squares together and cutting through the diagonal. Just cut triangles and sew them together this easy, accurate way.
1. Place 2 fabrics right sides together and cut strips as wide as one dimension of the template. For the example shown below with Set A, Template #6, the strip width would be 2". Do not separate the strips after cutting the triangles. To save time, stack as many layers as you are comfortable rotary cutting. Don't forget to put the fabrics right sides together in pairs as you layer them.
2. Place the triangle template on strips and rotary cut, rotating the template to conserve fabric. Don't forget to nip the corners (this is easiest to do after the triangles are cut).
Do not separate the triangles after cutting - leave them in pairs, right sides together, as they are now ready for sewing.
3. Sew pairs of triangles to make half-square triangle units, feeding one pair after another under the sewing machine needle until all pairs are sewn. Do not clip apart until after the squares are pressed open (step 5).
4. Arrange the chain on the ironing board with the darker triangles on top, so the seam allowance will automatically go toward it when you press. (If your design dictates, press toward the lighter fabric.)
5. Clip the units apart.
Excerpted from the Encyclopedia of Patchwork Blocks, Volume 2 published by Michell Marketing, Inc. ©1995 Martha G. Michell