DRILL RODS: The tool steel drill rod pieces (O-1, A-2, D-2, H-13, S-7, M-2, and W-1) are usually machined in the annealed state and then heat treated to make hardened, long lasting tools. The Applications Table below shows the classes, steel grades, hardening methods, and typical applications for Drill Rod. To use the table, find the class in the left column. To find out what is drill rod used for, find the steel grade in the table below and read the applications in the right column of the same row. DRILL PIPES: Available Ranges: Sizes : 3",3 ½", 4 ½" & 5 ½" Length : 5', 10', 13', 15', 20' & 30'