Temperature management for a cryogenically cooled boring tool

A cryogenically cooled boring tool which reduces the effect of cryogen coolant on a workpiece caused by coolant leakage and coolant exhaust, the boring tool comprising:

• a tool body having at least one cartridge for holding a cutting tool insert;
• a coolant flow path within the tool body for supplying cryogenic coolant to the cutting tool insert and at least one internal exhaust path that is internal to the tool body for conducting coolant from the cutting tool insert to atmosphere;
• the coolant flow path comprising a feed path in the cutting tool body and a feed path in the cartridge;
• a feed transfer tube for connecting the feed path in the cutting tool body with the feed path in the cartridge;
• and
• a first insulating tube lining at least a portion of the feed path in the cutting tool body and a second insulating tube lining at least a portion of the feed path in the cartridge, wherein the feed transfer tube is press fit into the ends of the first and second insulating tubes, and wherein the shrinkage rates of the feed transfer tube and the first and second insulating tubes cause the press fit of the said insulating tubes to tighten the seal between the said insulating tubes and the feed transfer tube when cryogenic coolant flows through the coolant flow path to prevent leakage of cryogenic coolant from the coolant flow path.