I checked the first batch of siggy's that I had made and discovered that they were all about 1/8" too big across the diamond... Obviously a systematic error. Unfortunately when I tried to take in the edges of the diamond they were not 5" around the edge.
So I have chosen a better method for me. Each time I make 1 siggy square and 4 half square triangles (HST) that I will use in a later project.
Step 1. Cut 5" Cream square, and 4 3" squares in feature fabric.
Step 3. Mark inner diamond within the first so that the diagonal is 4 1/2" across I find this is a scant 1/4" in from the first diamond. This will be the sewing line
Step 5. Sew a second line of stitching 1/4" outside the cutting line - the makes the HST
Step 6 Cut on cutting line and iron.
Step 7 Repeat steps 4,5,6 using the other 2 corners of the cream square.
Step 8 Trim of any excess feature fabric remembering the square has a minimum size of 5"
Step 9. Decorate, Sign, date and place on the siggy swap. i have tried several type of decorating - try to find something that said something about me.The 2 samples below are decorated from my large collection of vintage buttons and laces.I will make most of my siggies with lace as this is less heavy and less likely to be inconvenient during piecing. If you are in the swap and would like the buttons please let me know.