The Importance of a Crisp Grid Pattern and Proper Grid Measuring Technique
The correct way to use the Mylar strip is to measure from the center-width locations of the boundary line around the circumference of the now-deformed ellipse. Measuring from inside-to-inside or outside-to-outside is wrong! With a fuzzy ellipse boundary line (old stencil, poor gridding technique, etc.), it is not hard to make measurement errors more severe than just measuring the outside-to-outside dimensions of a crisp circle/ellipse. The width of the line [...]