My dad has me altering some of his shorts this summer. He can't find ones that don't come to his knees, so I'm shortening them. However, he also has another problem. He is a contractor, so he is really rough on his clothes, and after only a week his shorts wear out at the hem (at the very base, and also next to the hem stitching). Does anyone know of a way to reinforce the hem or a trick that will avoid holes developing at the stitching?