While some blame math and some blame accuracy, most everyone agrees that triangle-squares can be difficult to make. The first challenge is cutting the squares in measurements involving eighths, which aren't always clearly evident on a ruler. Second, extra care must be taken not to stretch the bias seam allowances when handling and sewing them. Here are some tips for making precise triangle-squares.

1. Cut off the trianglular dog-ears that result when piecing triangle-squares. This will allow you to add the triangle-squares to other pieces with more precision.

2. A scant seam allowance matters. When making triangle-squares, the distance you sew away from the marked diagonal lines should be just a little narrower than 1/4". This scant 1/4" seam allowance will give you the extra few threads you need to get precise triangle-squares. We recommend you still check the size and, if necessary, square up the block.

3. Make your triangle-squares larger than needed, then trim them down to size. Cut the initial squares 1/8" larger than specified. Using your preferred assembly method, make triangle-squares. Square each one up by lining up the 45° line on your ruler with the seam line and trimming the unit to the designated size. While this takes extra time, the precision is worth it for a lot of quilters, including many of our designers (and they're the pros!).