The tool holder range DAndrea CT is the acronym for Calettamento Termico (Thermal Rim), namely a system that exploits arbor thermal expansion (generated through specific machines heating the endpoint of the already mentioned tool holders) so as to allow the introduction of hard-metal or or HSS machine tools. The subsequent cooling, bringing the tool holder back to its original shape, blocks the machine tools steadily and safely in order to perform even complex operations such as the opening of caves with elevated rpm and high speeds.
The tool holder, brought at a temperature of 300° - 400° expands in a few seconds welcoming the machine tool (cold) within a hole. When the tool holder is cooled (getting shrinked) and returning to its original size, it creates a high clamping force all around the machine tool making the whole system extremely stable. Thanks to the thorough couplings between the tool holder hole (which is rebored) and the machine tool shank (rebored as well), maximum precision concentricities are obtained within 3 micron. All tool holders are balanced at 25.000 rpm.
Such cosntructional features provide doubtless advantages: a better finishing of machined surfaces, a far longer duration of machine tools and a high stability of the tool-holder-machine tool system with a consequent safeguard of the rotating machine and bearings