Drilling tool for producing an undercut in a predrilled cylindrical hole

摘要

A drilling tool for producing an undercut in a predrilled cylindrical hole (22) has a hollow-cylindrical drill shank (1). At its front end, the drill shank has cutting edges (8, 26) which can be pressed radially outwards by means of an expanding element (5, 27) which can be pushed into the drill shank (1). The expanding element (5, 27) is stepped to the inside at the front end so that the expanding action is ended abruptly and the cutting edges returning into the initial position enable the drilling tool to be pulled effortlessly out of the conically undercut drill hole. <IMAGE>