Proper Dimensional Integrity And Proper Tracking Provide Cleaner Cuts And Longer Runs Our rotary tube cutoff knives are manufactured from tool steel alloys and precisely heat-treated to meet your individual cutting requirements. Our heat-treating and tempering processes eliminate decarburization, and precise temperature control insures knives with consistently uniform hardness. The end result: a rotary tube cutoff knife that has proper dimensional integrity and will track properly, thus providing you with a cleaner cut and longer run.