A clamp is a component that serves to firmly and precisely clamp the work tool, in this case the cutter, to the milling machine itself. It is a metal sleeve with slots that tightens evenly when the clamping nut on the machine spindle is tightened. This tightening clamps the cylindrical part of the cutter, known as the "shank", firmly and precisely. Each collet is made for a specific shank diameter, for example 6mm, 8mm or 12mm, and for safe and accurate milling it is essential that the diameter of the collet matches the shank diameter of the tool being used. If there are several different sized chucks in the package, this expands the possibilities of the milling machine as it allows the use of tools with different shank diameters.