Profile: Delta Tool & Polishing Supplies Co., Inc. specializes in polishing tools and power tools. Our products include reamers, counter bores, tread gages, chucks, socket screws and tapping heads. We offer diamond needle files that are 5½" long and have a 2½" diamond surface. They are available in one surface fineness. The diamond rifflers are double ended with diamond coating on both ends. They have an overall length of 6".