Patent ID: 7552610

Claim:
A method of forming a thread in a metal plate comprising the steps of: providing a thread forming tool comprised of a pilot hole forming portion having a tapered shape, the pilot hole forming portion having a first spiral groove, and a thread forming portion having a second spiral groove; rotating the thread forming tool in a first direction that is opposite to a direction of the first spiral groove of the pilot hole forming portion; lowering the thread forming tool toward the metal plate such that the pilot hole forming portion contacts the metal plate; forming a hole in the metal plate with the pilot hole forming portion while simultaneously rotating the thread forming tool in the first direction; rotating the thread forming tool in a second direction that is the same as a direction of the second spiral groove of the thread forming portion; lowering the thread forming tool such that the thread forming portion contacts the metal plate; and forming an internal thread at the hole with the thread forming portion while simultaneously rotating the thread forming tool in the second direction.