Sublimationblankcompany.com has sold thousands and thousands of our awesome waffle weave kitchen towels. It's our #1 selling item to date, and each one is machine cut to an exact size. On exactly 2 occasions, we had a customer think a towel was not cut straight or was crooked. We helped them problem solve, and here is the trick to it:
Don't just plop your kitchen towel sublimation blank onto your heat press and attempt to find center to place your artwork. You are dealing with a piece of fabric that moves and stretches, after all. Waffle weave is a loose fabric with lots of pull and a stretchy nature, so it can appear crooked. But it really isn't!
Place your towel on a flat surface and fold it half making sure that your corners and your edges meet up. You will need pull your bottom edges into place so that they all are touching evenly. NOW your towel is straight and ready for artwork placement!
Since most folks display their towels folded in thirds, you place your art in the very center. You can check yourself by folding your towel in half again vertically, like this: