Main body of a cutting tool with interchangeable tip and cutting tool with interchangeable tip

Abstract

Main body (3) of a cutting tool (1) with replaceable tip, comprising: a cylindrically shaped cylindrical section (32) consisting of a first metallic material and extending in an axial direction (AX); and an internal threaded section (33) which is provided on an inner circumference (40) of the cylinder section (32) and can be screwed to an external threaded section (24) of a cutting head (2), wherein the internal threaded section (33) comprises the following: a first internal thread section (34) consisting of a second metal material different from the first metal material, and wherein the first internal thread section (34) extends in a section between a top of an internal thread crest (37) of the internal thread section (33) and a section (38) corresponding to an effective diameter (D2) of the internal thread section (33); and a second internal thread section (35) consisting of the first metal material and continuously transitioning into the inner circumference (40) of the cylindrical section (32), wherein the second internal thread section (35) is a remaining section of the internal thread section (33) without the first internal thread section (34), and wherein the first internal thread section (34) is connected to the second internal thread section (35).

Description

[Technical field]

[0001] The present invention relates to a main body of a cutting tool with an interchangeable tip and a cutting tool with an interchangeable tip. [State of the art]

[0002] A replaceable-tip cutting tool, in which a cutting head can be mounted on and removed from a main body, is a known type of cutting tool that performs cutting operations on a workpiece by being driven by a rotary motion from a machining center or similar device. If the cutting edge of the replaceable-tip cutting tool becomes damaged, it is possible to replace only the cutting head and reuse the main body. If both the main body and the cutting head are made of carbide, the replaceable-tip cutting tool is susceptible to damage from vibration shock in the threads of an external threaded section or an internal threaded section, where the external and internal threaded sections connect the main body and the cutting head.To address this problem, in a cutting tool disclosed in patent literature 1, an insert which has a lower stiffness than the carbide is installed in the internal thread section of the main body in such a way that the main body and the cutting head are fastened to each other by screwing the external thread section of the cutting head into the insert. {List of counter-arguments}

[0003] JP 4 993 528 B2 describes a cutting tool in which the amount of waste from a main body unit and a cutting head, as well as the oscillation during the cutting process, can be minimized. The cutting tool comprises a steel screw thread insert, which has a lower strength than carbide, and is positioned between an external thread unit and an internal thread unit.

[0004] US Patent 2014 / 0056658A1 describes a cutting head with a conical shaft section having an outer circumferential surface and a helical groove. The cutting head is attached to a shaft by a mounting attachment in the form of a spiral winding. The shaft has a conical opening with an inner surface and a helical groove.

[0005] WO 2013 / 057 778 A1 describes a holder for a cutting tool with an interchangeable head, comprising a holder main body and a tubular coupling element made of a metal material that has a lower hardness than the holder main body.

[0006] DE 102 55 270 A1 describes a tool comprising an integrated fastening device for the detachable fastening of a cutting insert to a tool holder.

[0007] DE 10 2013 100 939 A1 describes a tool holder for a screw-in tool with a holder body that includes a receiving opening with an internal thread and a support area with at least one guide surface for precise positioning of the screw-in tool in the tool holder. [Summary of the invention]

[0008] If, in the known cutting tool described above, both the diameter of the external threaded section formed at the end of the cutting head and the size of the main body are fixed, the diameter of the internal threaded section must be larger than that of the external threaded section by the amount required to allow the insert to be fitted. The radial thickness of the main body, which is formed from the carbide, must therefore be reduced, thereby decreasing the stiffness of the main body.

[0009] One object of the present invention is to provide a main body of a cutting tool with an interchangeable tip and a cutting tool with an interchangeable tip which, in a case where a cutting head can be mounted on and removed from the main body, can prevent vibration during the cutting operation while maintaining the rigidity of the main body.

[0010] According to a first aspect of the present invention, a main body of a cutting tool with an interchangeable tip is provided, and the main body of a cutting tool with an interchangeable tip comprises a cylindrically shaped cylinder section formed from a first metallic material and extending in an axial direction; and an internally threaded section provided on an inner circumference of the cylinder section and which can be screwed onto an externally threaded section of a cutting head. The internally threaded section comprises a first internally threaded section and a second internally threaded section. The first internally threaded section is made of a second metallic material that is different from the first metallic material. The first internally threaded section extends in a section between a top surface of an internally threaded tip of the internally threaded section and a section corresponding to an effective diameter of the internally threaded section.The second internal thread section consists of the first metal material and transitions smoothly into the inner circumference of the cylindrical section. The second internal thread section is a remaining portion of the internal thread section, excluding the first internal thread section. The first internal thread section is connected to the second internal thread section.

[0011] In the main body of a cutting tool with an interchangeable tip, as described in the first aspect, the external threaded section of the cutting head is screwed to the internal threaded section, which comprises the first and second internal threaded sections. Using a metal material with relatively low stiffness for the first internal threaded section and a metal material with relatively high stiffness for the second internal threaded section and the cylindrical section allows for maintaining the stiffness of the main body while simultaneously reducing the possibility of damage to the thread crests of the external or internal threaded sections from vibration shock. The external and internal threaded sections connect the main body and the cutting head.

[0012] According to the first aspect of the main body of a cutting tool with a replaceable tip, the first metal material can be an alloy with a density of at least 10 grams per cubic centimeter, and the second metal material can be a type of steel. According to this aspect of the main body of a cutting tool with a replaceable tip, the rigidity of the cylindrical section can be ensured by making the cylindrical section from the first metal material, which has a density of at least 10 grams per cubic centimeter. Furthermore, making the first internal thread section from a type of steel reduces the possibility of damage to the thread crests of the external or internal thread sections from vibration shock, where the external and internal thread sections connect the main body and the cutting head.

[0013] According to the first aspect of the main body of a cutting tool with a replaceable tip, the thickness of the cylindrical section in a radial direction can be greater than the thickness of the internal thread section in the radial direction. According to this aspect of the main body of a cutting tool with a replaceable tip, the rigidity of the cylindrical section can be ensured because its thickness in the radial direction is greater than that of the internal thread section.

[0014] According to the first aspect, the main body of a cutting tool with a replaceable tip can further comprise a cylindrically shaped front end section on the front end of the cylindrical section and the internal thread section. The cylindrically shaped front end section can be made of the second metal material and incorporate a tapered section that transitions smoothly into the external thread section of the cutting head. The tapered section has a smaller diameter on the external thread section side. According to this aspect of the main body of a cutting tool with a replaceable tip, the tapered section that transitions smoothly into the external thread section of the cutting head can be incorporated by the front end section made of the second metal material.Therefore, the main body of a cutting tool with a replaceable tip is better able to reduce the possibility of damage to the thread tips of the external thread section or the internal thread section by the vibration shock, where the external thread section and the internal thread section connect the main body and the cutting head, than would be the case if the front end section were not provided.

[0015] According to a second aspect of the present invention, a main body of a cutting tool with an interchangeable tip is provided, and the cutting tool with an interchangeable tip comprises the main body of a cutting tool with an interchangeable tip according to the first aspect and a cutting head with an external threaded section which, when screwed onto the internal threaded section of the main body, comes into contact with both the first internal threaded section and the second internal threaded section.

[0016] In the cutting tool with replaceable tip, as described in the second aspect, the external threaded section of the cutting head is screwed to the internal threaded section, which comprises the first and second internal threaded sections. Using a metal material with relatively low stiffness for the first internal threaded section and a metal material with relatively high stiffness for the second internal threaded section and the cylindrical section allows for maintaining the stiffness of the main body while also reducing the possibility of damage to the thread crests of the external or internal threaded sections from vibration shock, with the external and internal threaded sections connecting the main body and the cutting head.In the cutting tool with a replaceable tip, the external thread section of the cutting head comes into contact with both the first and second internal thread sections. Therefore, in this cutting tool, the second internal thread section allows the cutting head to be firmly attached to the main body, just as the first internal thread section reduces vibration at the thread crests of the external or internal thread sections, with the external and internal thread sections connecting the main body and the cutting head. [Brief description of the drawings] [ Fig. 1] Fig. Figure 1 is a partial sectional view of a cutting tool 1, which is provided with a cutting head 2 and a main body 3; [ Fig. 2] Fig. Figure 2 is an enlarged view of an external thread section 24 and an internal thread section 33 in sectional view in Fig. 1; [ Fig. 3] Fig. Figure 3 is an explanatory figure for a manufacturing process for the main body 3; [ Fig. 4] Fig. 4 is a diagram that presents evaluation results for a work sample; and [ Fig. 5] Fig. Figure 5 is a diagram that presents evaluation results for a comparative example. [Description of embodiments]

[0017] A preferred embodiment of the present invention is explained below with reference to the accompanying drawings. The structural design of a cutting tool with an interchangeable tip 1 (hereinafter referred to as the "cutting tool") of the present invention is described with reference to Fig. 1 explained. In the following explanation, AX denotes a longitudinal axis of the cutting tool 1, and in the axial direction of the axis AX, the front end of the cutting tool 1 with respect to a main body 3 is the end at which a cutting section 21 of a cutting head 2 is provided, and the rear end is the end of the cutting tool 1 opposite the front end. In a plane that is orthogonal to the axis AX, the direction away from the axis AX is called the radial direction. 1. Physical design of the cutting tool 1

[0018] As in Fig. As shown in Figure 1, the cutting tool 1 is a cutting tool that performs cutting work on a workpiece by being driven by a rotary drive from a machining center or the like. More precisely, the cutting tool 1 is a cutting tool with an interchangeable tip, provided with the cutting head 2 and the main body 3, wherein the cutting head 2 can be mounted onto and removed from the main body 3. The cutting head 2 is made of a hard metal formed by pressure sintering of tungsten carbide or the like. The cutting head 2 is provided with the cutting section 21, a body section 22, a tapered section 23, and an external threaded section 24 in that order from the front end to the rear end in the axial direction.The cutting section 21 is a section for performing the cutting work on the workpiece, and the cutting section 21 comprises a circumferential cutting edge, an end cutting edge, a chip pocket, an end-face chip groove, and the like, all of which are known. The body section 22 and the tapered section 23 are arranged between the cutting section 21 and the external threaded section 24. The diameter of the body section 22 is larger than the diameter of the tapered section 23. Beneath the surfaces of the body section 22, there is a surface 25 where the body section 22 is connected to the tapered section 23, substantially orthogonal to the axial direction. The tapered section 23 is tapered such that the tapered section has a smaller diameter on the side facing the external threaded section 24.The external threaded section 24 is connected to the rear end of the tapered section 23, and the external threaded section 24 is provided with external threads around the outer circumference of the external threaded section 24.

[0019] As in Fig. As shown in Figure 2, the main body 3 is the main body of the cutting tool with an interchangeable tip, extending in the axial direction, and the cutting head 2 can be mounted onto and removed from the main body 3. The main body 3 is provided with a front end section 31, a cylindrical section 32, internally threaded sections 33, and a base section 39. The front end section 31 is located at the front end in the axial direction of the main body 3, and the front end section 31 comes into contact with the surface 25 of the cutting head 2 when the cutting head 2 is mounted into the main body 3. The rear edge of the front end section 31 is connected to the front ends of the cylindrical section 32 and the internally threaded sections 33.The front end section 31 is formed from a second metal material at the front ends of the cylindrical section 32 and the internal thread sections 33, and the front end section 31 is a cylindrical section that accommodates the tapered section 23 which transitions steadily into the external thread section 24 of the cutting head 2.

[0020] The cylindrical section 32 is formed from a first metallic material and is a cylindrical section extending in the axial direction with a diameter D. The internal threaded sections 33 are provided on a virtual inner circumference 40 of the cylindrical section 32 and are sections that are formed internal threads which can be screwed onto the external threaded section 24 of the cutting head 2. The inner diameter of the internal threaded sections 33 is D3, and the core diameter of the internal threaded sections 33 is D1.

[0021] Each of the internal thread sections 33 is provided with a first internal thread section 34 and a second internal thread section 35. The first internal thread section 34 is the section of the internal thread section 33 between the top of an internal thread crest 37 of the internal thread section 33 and a section located on the side of the internal thread crest 37 of an internal thread root 36 and on the side of the internal thread root 36 of a section 38, which corresponds to an effective diameter D2 of the internal thread section 33. The first internal thread section 34 consists of the second metal material, which is different from the first metal material. As in Fig. As shown in Figure 1, in the present embodiment the first internal thread section 34 is in a state in which the external thread section 24 of the cutting head 2 is attached to the internal thread sections 33 of the main body 3, the section between the internal thread tip 37 of the internal thread section 33 and a section located on the side of the internal thread tip 37 of an external thread tip 26 and on the side of the internal thread root 36 of the section 38, which corresponds to the effective diameter D2 of the internal thread section 33.

[0022] The second internal thread section 35 is a section that seamlessly transitions into the virtual inner circumference 40 of the cylindrical section 32, and is a remaining section of the internal thread section 33 excluding the first internal thread section 34. The virtual inner circumference 40 of the cylindrical section 32, the second internal thread section 35, is defined as an inner circumference connecting the internal thread bases 36 in the axial direction. The second internal thread section 35 is made of the same metal material as the first cylindrical section 32. A thickness T1 of the cylindrical section 32 in the radial direction is greater than a thickness T2 of the internal thread section 33 in the radial direction.

[0023] The base section 39 is located on the rear side of the internally threaded sections 33. The base section 39 forms the bottom of a hole section formed by the front end section 31 and the internally threaded sections 33 of the main body 3. The base section 39 is made of the same second metal material as the first internally threaded sections 34.

[0024] The first and second metal materials are selected taking into account the material of the cutting head 2. In particular, it is preferable that the stiffness of the first metal material be greater than that of the second metal material. Since the cutting head 2 is made of a cemented carbide in the present embodiment, the first metal material in the main body 3 is, for example, an alloy with a density of at least 10 grams per cubic centimeter. An alloy with a density of at least 10 grams per cubic centimeter would be, for example, a cemented carbide or a tungsten alloy. The second metal material is, for example, a type of steel. The type of steel can be structural steel, spring steel, bearing steel, tool steel, stainless steel, chromium-molybdenum steel, or the like.

[0025] When the cutting head 2 is mounted on the main body 3, the external threaded section 24 of the cutting head 2 is screwed into the internal threaded sections 33 of the main body 3. The internal threaded sections 33 of the main body 3 are provided with the first internal threaded sections 34, formed from the second metal material, and the second internal threaded sections 35, formed from the first metal material. In the present embodiment, when the external threaded section 24 of the cutting head 2 is screwed into the internal threaded sections 33 of the main body 3, the external threaded section 24 is in contact with both the first internal threaded sections 34 and the second internal threaded sections 35 of the internal threaded sections 33. The second metal material, formed from steel, which has a lower stiffness than the first metal material, is inserted between the external threaded section 24 and the second internal threaded sections 35.Therefore, the effect of the vibration of the cutting head 2 on the main body 3 can be dampened. The external threaded section 24 can be firmly attached to the internal threaded sections 33. Accordingly, the vibration of the cutting head 2 during the cutting operation can be more effectively suppressed. This makes it possible to prevent damage to a cutting edge formed in the cutting section 21, thereby extending the service life of the cutting head 2 and reducing the number of discarded cutting heads 2. 2. Manufacturing process for the main body 3 of the cutting tool 1

[0026] The manufacturing process for the cutting tool 1 is described with reference to Fig. 3 explained. As in Fig. As shown in Figure 3, an element 41, made of the first metal material, and an element 42, made of the second metal material, are prepared, and the element 42 is fitted into the element 41 (a fitting operation). The element 41 is a cylindrical element with diameter D and has a recessed section centered on the axis AX, which extends from the front end to the rear end, and which has a diameter approximately equal to the effective diameter D2 of the internal threaded section 33. A section on the front end face (the upper end face in Figure 3) Fig. 3) Element 42 is a cylindrical section with diameter D, and element 42 includes a cylindrical projecting section with diameter D2 on a rear end face of element 42. Element 41 and element 42 are joined by fitting the projecting section of element 42 into the recessed section of element 41 (a joining operation). The work to cut the internal threaded sections 33 on the joined unit of element 41 and element 42 is carried out using a threading cutter or the like (a fastening operation). The main body 3, which is provided with the internal threaded sections 33, is thus produced. 3. Evaluation test of the cutting tool 1

[0027] To evaluate the vibration during cutting operations, tests were conducted using cutting tool 1 in the embodiment described above as a working example and a cutting tool in which the external thread section consists only of the first metal material as a comparison example. In the working example, a cemented carbide is used for the first metal material of the main body 3, and chromium-molybdenum steel (SCM440 according to JIS) is used for the second metal material. In the comparison example, the main body consists only of a cemented carbide. The working example and the comparison example differ only in the materials used for the internal thread sections of the main body and are otherwise identical in design.

[0028] The following are the test conditions for the working example and the comparison example. The workpiece material is stainless steel (SUS304 according to JIS). The machining center is a vertical machining center. The tool diameter is 16 millimeters. The tool protrudes 50 millimeters. The cutting speed is 600 meters per minute. The spindle speed is 11,950 revolutions per minute. The feed rate is 3,580 millimeters per minute. The feed is 0.1 millimeters per tooth (mm / Z). The depth of cut (grooves) is 8 millimeters. Cooling is provided by compressed air.

[0029] The cutting operation on the side surface was performed on the workpiece using the corresponding cutting tools from the working example and the comparison example, and the cutting resistance acting on the cutting tools was measured. The test results for the working example are in Fig. 4 is shown and the test results for the comparison example are in Fig. 5 shown. In the Fig. 4 and Fig. 5 is the vertical axis of the cutting resistance (N) and the horizontal axis is the processing time (s). The diagrams in the Fig. 4 and Fig. Figure 5 shows the test results for Fx, Fy, and Fz in order from top to bottom. Fx is the vertical force component (main force component), acting in a direction perpendicular to the feed force component. Fy is the horizontal force component (feed force component), acting in the direction in which the cutting tool is advanced. Fz is the axial force component (thrust force component), acting in the axial direction of the cutting tool. The main force component, the feed force component, and the thrust force component are force components in the x-axis, y-axis, and z-axis directions, respectively, which are orthogonal to the cutting resistance.

[0030] As in the Fig. 4 and Fig. As shown in Figure 5, the mean value of the main force component Fx is -279 N in the comparison example compared to -437 N in the working example. The mean value of the feed force component Fy is -661 N in the comparison example compared to -718 N in the working example. The mean value of the shear force component Fz is -291 N in the comparison example compared to -355 N in the working example.

[0031] On the other hand, the mean amplitude of the principal force component Fx is 502 N (i.e., Fx = -279 ± 251 N) in the comparison example compared to 278 N (i.e., Fx = -437 ± 139 N) in the working example. The mean amplitude of the feed force component Fy is 422 N (i.e., Fy = -661 ± 211 N) in the comparison example compared to 274 N (i.e., Fy = -718 ± 137 N) in the working example. The mean amplitude of the shear force component Fz is 271 N (i.e., Fz = -291 ± 135 N) in the comparison example compared to 178 N (i.e., Fz = -355 ± 89 N) in the working example.

[0032] A comparison of the mean values ​​of the cutting resistance (N) in the working example and the comparison example shows that the mean values ​​of the shear force component Fz and Fz' are essentially the same. The mean value of the main force component Fx in the working example is 158 N lower than the mean value of the main force component Fx in the comparison example. A comparison of the mean values ​​of the cutting resistance amplitude (N) in the working example and the comparison example shows that the mean value of the main force component amplitude Fx in the working example is 224 N lower than the mean value of the main force component amplitude Fx in the comparison example, or approximately 55% of the mean value of the main force component amplitude Fx in the comparison example.The mean amplitude of the feed force component Fy in the working example is 168 N lower than the mean amplitude of the feed force component Fy in the comparison example, or approximately 62% of the mean amplitude of the feed force component Fy in the comparison example. The mean amplitude of the shear force component Fz in the working example is 93 N lower than the mean amplitude of the shear force component Fz in the comparison example, or approximately 67% of the mean amplitude of the shear force component Fz in the comparison example.

[0033] The results described above confirm that the cutting tool 1 of the working example exhibits fewer vibrations (smaller amplitude of cutting resistance) during cutting than the cutting tool of the comparison example. Based on these results, it is assumed that the cutting head 2 of the working example can be attached more precisely to the main body 3 than in the comparison example, because the first internal thread section 34, which consists of the second metal material, prevents resonance.That is, it was confirmed that providing the internal thread sections 33 with the first internal thread sections 34, which consist of the second metal material, and the second internal thread sections 35, which consist of the first metal material, as in the cutting tool 1 of the working example, prevents the vibration that occurs during the cutting operation more effectively than in the comparison example where the internal thread sections consist of only a single material.

[0034] In the embodiment described above, the cutting tool 1, the cutting head 2, and the main body 3 are examples of a cutting tool with an interchangeable tip, a cutting head, and a main body of a cutting tool with an interchangeable tip, respectively, according to the present invention. The first internal thread sections 34, the second internal thread sections 35, and the internal thread sections 33 are examples of a first internal thread section, a second internal thread section, and an internal thread section, respectively, according to the present invention. The internal thread root 36 and the internal thread tip 37 are examples of an internal thread root and an internal thread tip, respectively, according to the present invention. The front end section 31 and the cylindrical section 32 are examples of a front end section and a cylindrical section, respectively, according to the present invention.The tapered section and the external thread section 24 are examples of a tapered section and an external thread section respectively of the present invention.

[0035] In the main body of a cutting tool with an interchangeable tip in the embodiments described above, the external threaded section 24 of the cutting head 2 is screwed to the internal threaded section 33, which comprises the first internal threaded section 34 and the second internal threaded section 35. The use of a metal material with relatively low stiffness for the first internal threaded section 34 and a metal material with relatively high stiffness for the second internal threaded section 35 and the cylindrical section 32 makes it possible to maintain the stiffness of the main body 3 and to reduce the possibility of damage to the thread tips of the external threaded section 24 or the internal threaded section 33 by vibration shock, with the external threaded section 24 and the internal threaded section 33 connecting the main body 3 and the cutting head 2.

[0036] In the main body 3 of the cutting tool 1, the first metal material is an alloy with a density of at least 10 grams per cubic centimeter, and the second metal material is a type of steel. The rigidity of the cylindrical section 32 of the main body 3 of the cutting tool 1 can be ensured by making the cylindrical section 32 from the first metal material, which has a density of at least 10 grams per cubic centimeter. Furthermore, making the first internal thread section 34 from a type of steel reduces the possibility of damage to the thread crests of the external thread section 24 or the internal thread section 33 from vibration shock, where the external thread section 24 and the internal thread section 33 connect the main body 3 and the cutting head 2.

[0037] In the main body 3 of the cutting tool 1, the thickness T1 of the cylindrical section 32 in the radial direction is greater than the thickness T2 of the internal thread section 33 in the radial direction. Therefore, the stiffness of the cylindrical section of the main body 3 of the cutting tool 1 can be ensured because the thickness T1 of the cylindrical section 32 in the radial direction is greater than the thickness T2 of the internal thread section 33 in the radial direction.

[0038] The main body 3 of the cutting tool 1 comprises a cylindrically shaped front end section on the front end of the cylindrical section 32 and the internally threaded section 33. The cylindrically shaped front end section is made of the second metal material and accommodates the tapered section 23, which transitions smoothly into the externally threaded section 24 of the cutting head 2. The tapered section 23 has a smaller diameter on the side facing the externally threaded section 24. Therefore, in the main body 3 of the cutting tool 1, the tapered section 23, which transitions smoothly into the externally threaded section 24 of the cutting head 2, can be accommodated by the front end section made of the second metal material.Therefore, the main body 3 of the cutting tool 1 is better able to reduce the possibility of damage to the thread tips of the external thread section 24 or the internal thread section 33 by the vibration shock, with the external thread section 24 and the internal thread section 33 connecting the main body 3 and the cutting head 2, than would be the case if the front end section 31 were not provided.

[0039] The main body 3 of the cutting tool 1 comprises the main body 3 and the cutting head 2 with the external threaded section 24, which, when screwed onto the internal threaded section 33 of the main body 3, comes into contact with both the first internal threaded section 34 and the second internal threaded section 35. In the cutting tool 1, the external threaded section 24 of the cutting head 2 comes into contact with both the first internal threaded section 34 and the second internal threaded section 35. Therefore, in the cutting tool 1, the second internal threaded section 35 allows the cutting head to be firmly attached to the main body, just as the first internal threaded section 34 allows the vibrational shock of the thread crests of the external threaded section or the internal threaded section to be reduced, with the external threaded section 24 and the internal threaded section 33 connecting the main body 3 and the cutting head 2.

[0040] The cutting tool with interchangeable tip and the main body of the present invention are not limited to those described in the embodiment described above, and various modifications can be made within the scope of the present invention. For example, the modifications described below can be made.

[0041] The numerical values ​​mentioned in the embodiment described above are only examples, and other numerical values ​​may also be used. A cutting tool such as an end mill, a drill, a tap, and the like may also be used as a cutting tool. The types of external and internal threads are not specifically limited to metric threads, UTS standard threads, saw threads, or the like. The external threads may be cut in accordance with the cutting direction of the cutting head (the direction in which the threads clamp relative to the cutting resistance of the cutting head). At least one of the front end section 31 and the base section 39 of the main body 3 may also be made of the first metal material. The second metal material only needs to be different from the first metal material.In particular, it is acceptable that the first metal material is not an alloy with a density of at least 10 grams per cubic centimeter. It is also acceptable that the second metal material is not a type of steel. Furthermore, it is acceptable that the thickness of the cylindrical section in the radial direction is not greater than the thickness of the internal threaded section in the radial direction. In a case where the external threaded section of the cutting head is screwed into the internal threaded sections of the main body, it is acceptable that the external threaded section only comes into contact with the first internal threaded sections.

Claims

[1] Main body (3) of a cutting tool (1) with replaceable tip, comprising: a cylindrically shaped cylindrical section (32) consisting of a first metallic material and extending in an axial direction (AX); and an internal threaded section (33) which is provided on an inner circumference (40) of the cylinder section (32) and can be screwed to an external threaded section (24) of a cutting head (2), wherein the internal threaded section (33) comprises the following: a first internal thread section (34) consisting of a second metal material different from the first metal material, and wherein the first internal thread section (34) extends in a section between a top of an internal thread crest (37) of the internal thread section (33) and a section (38) corresponding to an effective diameter (D2) of the internal thread section (33); and a second internal thread section (35) consisting of the first metal material and continuously transitioning into the inner circumference (40) of the cylindrical section (32), wherein the second internal thread section (35) is a remaining section of the internal thread section (33) without the first internal thread section (34), and wherein the first internal thread section (34) is connected to the second internal thread section (35). [2] Main body (3) of a cutting tool (1) with replaceable tip according to claim 1, wherein the first metallic material is an alloy with a density of at least 10 grams per cubic centimeter, and the second metal material is a type of steel. [3] Main body (3) of a cutting tool (1) with replaceable tip according to one of claims 1 and 2, wherein a thickness (T1) of the cylinder section (32) in a radial direction is greater than a thickness (T2) of the internal thread section (33) in the radial direction. [4] Main body (3) of a cutting tool (1) with replaceable tip according to one of claims 1 to 3, further comprising: a cylindrically shaped front end section (31) on a front end of the cylindrical section (32) and the internal thread section (33), which consists of the second metal material and accommodates a tapered section (23) which transitions steadily into the external thread section (24) of the cutting head (2), wherein the tapered section (23) has a smaller diameter on the external thread section side (24). [5] Cutting tool (1) with replaceable tip, comprising: the main body (3) of a cutting tool (1) with replaceable tip according to one of claims 1 to 4; and a cutting head (2) with an external threaded section (24) which, when screwed onto the internal threaded section (33) of the main body (3), comes into contact with both the first internal threaded section (34) and the second internal threaded section (35).

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