Drill guide

A drill guide, comprising,

• a main body with a flat base and a through aperture, for assisting the movement of a drill bit,
• a housing defined by said main body and having a tubular inner wall defining a through hole in correspondence with said through aperture,
• detachable and physically interchangeable drilling heads for guiding drill bits of different diameters, the heads designed to be optionally attached and fit into said tubular inner wall of said housing, and having respective inside through apertures of different diameters on each drilling head, one per drilling head, where the inside through apertures are specifically designed to guide drill bits of different diameters, the through aperture of the attached drilling head being in communication with the through aperture of the main body to allow the drill bit pass there through;
• a positioning device for attaching the drilling head in use in a set position inside the housing;
• and
• a retaining device for retaining any of the interchangeable drilling heads inside the housing;
• wherein the main body has seating for coupling a water tank to supply water to the aperture of the interchangeable drilling head in use through lateral windows, the lateral windows face each other and are defined in both the housing and in the drilling heads.