A tool of the "T" type used for milling metal products or other hard materials, such as for making grooves with undercuts on a workpiece holder or the like, said tool comprising: - a substantially axially symmetric shank comprising an end thereof provided with an appendage; - a head separated from said shank and joinable therewith, of substantially cylindrical or trunco-conical discoidal conformation having a greater diameter than said shank and delimited by two opposite faces (14, 15) of which the face facing said shank comprises a first slot, arranged with the main axis thereof parallel to the rotation axis of the tool, inside which a second slot which is concentric and arranged coaxially to the main slot is also obtained, where the second slot is smaller than the first slot; wherein said shank is provided with at least one central longitudinal channel, and in that said head is provided with holes arranged radially and communicating with said central channel, so that the mutual connection between the shank and the head causes a passage of refrigerant fluid introduced from the base of the shank and delivered by the radial holes of the head; characterised in that the end of the shank and/or its appendage are provided with radially arranged lateral holes and/or grooves placed in connection with the radial holes of the head; wherein the end of the shank is fixed to the inside of the slots (16, 17) by welding material which is placed in the slots (16, 17) based on the positioning of the lateral holes and/or grooves on the end of the appendage of the shank or on the end of the shank itself; wherein, when the lateral holes of the shank are placed in an advanced position on the end of the appendage to coincide with the radial holes placed at the second slot of the head, the welding material is placed on the bottom of the first slot; and wherein, when the lateral holes are placed on the end of the shank to coincide with the radial holes placed at the first slot, the welding material is placed on the bottom of the second slot. - a substantially axially symmetric shank comprising an end thereof provided with an appendage; - a head separated from said shank and joinable therewith, of substantially cylindrical or trunco-conical discoidal conformation having a greater diameter than said shank and delimited by two opposite faces (14, 15) of which the face facing said shank comprises a first slot, arranged with the main axis thereof parallel to the rotation axis of the tool, inside which a second slot which is concentric and arranged coaxially to the main slot is also obtained, where the second slot is smaller than the first slot; wherein said shank is provided with at least one central longitudinal channel, and in that said head is provided with holes arranged radially and communicating with said central channel, so that the mutual connection between the shank and the head causes a passage of refrigerant fluid introduced from the base of the shank and delivered by the radial holes of the head; characterised in that the end of the shank and/or its appendage are provided with radially arranged lateral holes and/or grooves placed in connection with the radial holes of the head; wherein the end of the shank is fixed to the inside of the slots (16, 17) by welding material which is placed in the slots (16, 17) based on the positioning of the lateral holes and/or grooves on the end of the appendage of the shank or on the end of the shank itself; wherein, when the lateral holes of the shank are placed in an advanced position on the end of the appendage to coincide with the radial holes placed at the second slot of the head, the welding material is placed on the bottom of the first slot; and wherein, when the lateral holes are placed on the end of the shank to coincide with the radial holes placed at the first slot, the welding material is placed on the bottom of the second slot.