Turbine driven power unit for a cutting tool

A turbine power unit for a cutting tool, the power unit comprising:

• a turbine housing having an interior space configured to receive therein a fluid powered turbine supported for rotation on a bearing that is a ball bearing or a roller bearing disposed within the turbine housing;
• a tool shank comprising an elongated portion and an end portion, wherein the turbine is directly coupled to the tool shank at the elongated portion, wherein the bearing is in direct contact with the elongated portion of the tool shank, wherein the end portion of the tool shank forms a cutting tip, and wherein the bearing, turbine and tool shank comprise a removable assembly;
• a service opening through the turbine housing into the interior space thereof, the service opening configured to permit installation and removal of the removable assembly into and out of the interior space of the turbine housing;
• a removable cover releasably securable to the turbine housing and disposed over the service opening and transitionable between an open configuration in which the removable assembly can be installed into and removed from the interior space of the turbine housing through the service opening, and a closed configuration in which the bearing is secured for operation within the turbine housing.