Inverse helical reamer

Reamer formed of a tang extended by a shank having a substantially helical shape ending in a point on the opposite side to the tang and having an edge turned towards the point, wherein:

• the shank consists essentially of a single flexible blade wound into a helix about an imaginary axis,
• at least the part of the edge turned towards the point is cutting and the direction in which the helix is wound is opposite to the direction of rotation normally provided for operating the reamer,
• the point comprises at least one part having a continuously circular cross-section perpendicular to the imaginary axis, and
• the tang comprises a boss, of which at least part of, the transverse section is continuously and non-helical and said continuously circular part has a radius equal to or greater than the largest radius vector of the helix.