Cutting Perfect Corner and Setting Triangles with Proper Grainline is Easy with These Rulers
Diagonal set quilts have two different half-square triangles: one for the corners and one for the setting triangles. Use this “no math” ruler to cut both triangles from the same-width strip of fabric.
a = The finished block size ise calculated and included ¼″ seam allowances.
b = The corner triangles are cut with the legs on straight grain.
c = The setting triangles that fill in the ends of the diagonal rows are cut with the hypotenuse on the straight grain.