Step and Pilot Tools may be incorporated in an application to eliminate two-three subsequent operations in a single hole. The use of a step tool dramatically reduces cycle time, scrap, and eccentricity between diameters.

Step Gundrills

Step drills have manufacturing limitations depending on extreme diameter ranges in the steps. Special carbide developing may sometimes be necessary due to the coolant hole location. Additionally, chip breakers may be required due to a lack of an inside angle which curls and breaks the chips under normal circumstances. Ideally using this type of drill yields virtually no eccentricity between diameters.

Pilot Drills

Non-cutting pilot drills are used to follow an existing hole while cutting a larger diameter and reducing cycle times plus minimizing eccentricity between holes.

Multi-Diameter Step Gundrills

Many parts require as many as two, three, or four various size holes in a single bore. Certain applications may allow a single multi-diameter gundrill to produce all or some of these holes, reducing machining time. Solid carbide tips ground to print tolerances enabling multiple diameters to be produced in a single pass.