40" x 46" Cutting Mat for Dingo Cabinet

A cutting mat is NOT a ruler and should not be used for precise measuring. Why? Because of the coefficient of expansion. Basically mats are made of a soft plastic, so they have agreater chance of expanding and contracting in different weather. Rulers are always made of acrylic which has a much, much smaller coefficient of expansion. As a matter of fact the coefficient of expansion on rulers is so small as to be practically non-existent for a quilter’s purpose. You should be using your ruler to measure precisely, and should be using the same ruler throughout theproject which is something every top quilt instructor teaches. Mats should be used only for general measuring and for cutting. They should never be used for precisemeasurements.