Cutting tool

Cutting tool for forming an undercut in a borehole drilled in a component of a hard material structure such as masonry, concrete and similar materials, comprising an axially elongated tubular drive shaft (1) having a first end and a second end, and a cutting member (4) mounted in and projecting outwardly from the first end of said drive shaft, said cutting member (4) comprises an axially extending shank section located within said drive shaft and having a first end and a second end, the first end of said shank section (5) projects outwardly from the first end of said drive shaft, and a cutting head (7) fixed to the first end of said shank section, said cutting head (7) having an outer surface with cutting members (7a) secured in the outer surface, wherein the improvement comprises means on said drive shaft and shank section for forming a ball joint at the second end of said shank section for pivotally supporting said cutting member, a central bore (3a) in said drive shaft located at said pivotal supporting means and having an axis co-axial with the axis of said drive shaft, a guidance bore in said drive shaft extending from said central bore to the first end of said drive shaft with said guidance bore changing from the central bore to a bore elongated transversely of the axial direction thereof at the first end of said drive shaft, and said guidance bore having guidance stop faces (3c) extending chordally of the axis of said drive shaft for guiding the pivotal movement of said cutting member in said guidance bore.