Reamer with a flat rectangular reversible cutting bit

A reamer comprising:

• a revolvable body with a right-angled recess which has a base surface and a support surface substantially at right angles to said base surface, at least one of said base surface and said support surface being displaced from a radius of the revolvable body;
• a base support on said base surface having approximately the form of a rectangular prism with a precision ground upper side and a precision ground lower side and a bore;
• a reversible cutting bit on said base support having approximately the form of a rectangular prism, with an upper side and a lower side parallel to each other, four parallel cutting edges, a pair of parallel support webs on side surfaces of the bit, each support web lying between a pair of cutting edges, a clearance rake between each cutting edge and a neighboring support web, a bore at approximately the middle of said cutting bit, a countersunk recess on said middle bore extending from said upper side of said cutting bit, and a countersunk recess on said middle bore extending from said lower side of said cutting bit;
• said cutting bit being arranged in said recess such that one of said upper and lower sides engages the upper side of the base support, said base support fixedly establishing a predetermined radial distance of the respective cutting edge from a longitudinal axis of said revolvable body, and one of said support webs abutting said support surface such that the force applied to the respective cutting edge by rotation of the revolvable body is at a slight angle to the plane of the upper surface;
• and
• a single screw with a countersunk head, which passes through said reversible cutting bit and said base support and is screwed into said base surface in said revolvable body to secure said reversible cutting bit and said base support on said base surface in said recess.