The holder for a head replacement-type cutting tool is provided with a holder main body and a tubular coupling member 3 which is housed in an attachment hole formed on the holder main body and made of a metal material lower in hardness than the holder main body. A recessed part is formed on an inner circumferential face of the attachment hole, the coupling member is engaged with the recessed part by firmly attaching the outer circumferential face thereof on the inner circumferential face of the attachment hole, and the coupling member is provided with an attachment screw part which is screwed into a head-side screw part formed at the replacement-type cutting head.

A rotary cutting tool includes a replaceable cutting head and a tool holder. The replaceable cutting head includes a forward cutting portion and a rearward mounting portion. The mounting portion includes a male coupling member that includes a straight external thread. The tool holder includes a female coupling member that includes a conical internal thread. When the rotary cutting tool is in a locked position, the external thread is threadingly engaged with the internal thread.

A cutter fastening assembly has a tool block, a fastening bolt, a fastening unit, a collet, and a cutter holder. The fastening bolt, the fastening unit, and the collet are mounted inside the tool block. The cutter holder has an assembling seat and a threaded hole. The assembling seat is integrally formed on the cutter holder and has a flange portion. The threaded hole is axially defined inside the flange portion and is screwed with the fastening bolt to keep the cutter holder connecting with the tool block.

A screwing tool includes a tool head and a tool shaft having an external thread. A first support section is disposed between the tool head and the external thread, and a second support section is disposed between the external thread and a free end of the tool shaft. The second support section has radially outwardly projecting supporting elements that are disposed at a distance from each other in the circumferential direction.

A tool receptacle for a screw-in tool having a main body, which has a receiving region including at least one conical contact surface for supporting a corresponding conical support surface of the screw-in tool. For thread-protection and for tightening with high concentricity and low production outlay, an insert is disposed in the main body, the insert is movable transversely with respect to the longitudinal axis of the main body and is rotationally-fixed with respect to the main body and has a mating thread for a thread on the screw-in tool.

An exchangeable tip cutting tool in which breakage of the threaded section and breakage of the thread ridges during installation of the machining head and under increased cutting load during cutting are limited and which is capable of performing machining with high efficiency; and a machining head and a holder to be used in the exchangeable tip cutting tool.

A replaceable cutting head includes a forward cutting portion and a rearward mounting portion. The mounting portion includes a male coupling member that protrudes rearwardly from a head base surface. The male coupling member includes forward and rearward bearing portions and an external thread located therebetween. The forward and rearward bearing portions include respective conically shaped forward and rearward head abutment surface. The forward and rearward head abutment surfaces have the same cone angle. When a cutting tool, including said cutting head and a tool holder having a female coupling member, is in a locked position, the external thread is threadingly engaged in the female coupling member and the forward and rearward head abutment surfaces conically abut corresponding conical shaped surfaces in the female coupling member.

A device for holding and securing a tool, in particular, a drill bit, on a machine tool, for example, a core drill, including an output shaft for transmitting a torque generated in the machine tool to the tool; and a union nut positioned around the output shaft for detachably connecting the output shaft to an attachment end of the tool.

The output shaft includes a locking ring and the union nut includes a washer disk, as well as an attenuator, the washer disk being positioned between the locking ring and the attenuator.

A cutter fastening assembly has a tool block, a fastening bolt, a fastening unit, a collet, and a cutter holder. The fastening bolt, the fastening unit, and the collet are mounted inside the tool block. The cutter holder has an assembling seat and a threaded hole. The assembling seat is integrally formed on the cutter holder and has a flange portion. The threaded hole is axially defined inside the flange portion and is screwed with the fastening bolt to keep the cutter holder connecting with the tool block.

A replaceable cutting head includes a forward cutting portion and a rearward mounting portion. The mounting portion includes a male coupling member that protrudes rearwardly from a head base surface. The male coupling member includes forward and rearward bearing portions and an external thread located therebetween. The forward and rearward bearing portions include respective conically shaped forward and rearward head abutment surface. The forward and rearward head abutment surfaces have the same cone angle. When a cutting tool, including said cutting head and a tool holder having a female coupling member, is in a locked position, the external thread is threadingly engaged in the female coupling member and the forward and rearward head abutment surfaces conically abut corresponding conical shaped surfaces in the female coupling member.