Originally Posted by SuzyMcQ
But, how do you determine your "straight" edge if the selvage isn't straight? Do you guess at straight on one of the sides and then go from there? Sounds like it......
Use a large square ruler on the corners. You need to cut on the outside of a ruler, not the inside. It doesn't have to be perfect. You can use the lines on a rotary cutting mat to help you get it straight.