A threading tool is disclosed that uses interchangeable guide inserts to ensure that pipes or rods of various diameters are maintained at a perpendicular angle to a threading die. The threading tool includes a housing and a guide insert. The housing includes a first opening at one end and a second opening at an opposite end. The housing defines a first region having a first width adjacent to the first opening and a second region having a second width adjacent to the second opening. The second width is greater than the first width. The guide insert is designed to fit through the first opening and is removably secured within the first region. The second region is shaped to fit a threading die, and the threading die is removably secured in the second region.