JP2006150508A - Cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting tool in which a cutting head can be firmly fixed to a body part when the body part and the cutting head are composed to be attachable/detachable. <P>SOLUTION: A tapered part 23a whose outer peripheral face is inclined to the axial center O is provided to a protruding part 23 protruding from a mating face 21 of the cutting head 2 in the cutting tool 1. A tapered hole 33a whose inner peripheral face is inclined corresponding to the tapered part 23a is provided to a recessed part 33 recessed to a mating face 31 of the body part 3 in the cutting tool 1. A key groove 22, which has an inclined part 22a inclined to the axial center O, is recessed to the outer peripheral face of the protruding part 23. A key 32 to be engaged with the key groove 22 is protruded to the inner peripheral face of the recessed part 33. The inclination direction of the inclined part 22a is set in the direction of drawing the cutting head 2 into the body part 3 side by cutting resistance during cutting. Consequently, the cutting head 2 can be firmly fixed to the body part 3 by tightly bringing the tapered part 23a into contact with the tapered hole 33a. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cutting tool, and more particularly to a cutting tool that can firmly fix a cutting head to a main body when a main body and a cutting head are configured to be detachable.

  In recent years, cutting tools that are held by a rotating machine such as a machining center and process a workpiece include those made of cemented carbide for the purpose of more efficient processing and longer life. Many have become popular.

  However, cemented carbide has a high material cost and is difficult to process, so solid type (shank integrated type) cutting tools increase the material cost and processing cost, which increases the product cost of the entire cutting tool. There was a problem of inviting.

  Therefore, Japanese Translation of PCT International Application No. 2004-507373 discloses a technique in which a tool head (cutting head) is detachably attached to a tool shaft (main body part). Specifically, in a state where a fixed short shaft (convex portion) protruding from the tool head and a clamp bracket recessed in the tool shaft to receive the fixed short shaft are fitted, A clamp fixing screw can be inserted into a through-hole formed in the clamp bracket.

As a result, the tool head can be fixed to the tool axis, and when the tool head is consumed, only the tool head can be replaced. The manufacturing cost can be reduced.
Japanese translation of PCT publication No. 2004-507373 (paragraph [0018], FIG. 1 etc.)

  However, as described above, in the conventional cutting tool, the tool head is fixed to the tool axis by inserting the clamp fixing screw through the fixed short shaft and the through hole formed in the clamp bracket. For this reason, the load on the through-hole is increased, so that the through-hole is damaged due to cutting resistance at the time of cutting, the opening area of the through-hole is increased, and the tool head is likely to wobble.

  The present invention has been made to solve the above-described problems, and a cutting tool capable of firmly fixing a cutting head to a main body when the main body and the cutting head are configured to be detachable. It is intended to provide.

  In order to achieve this object, a cutting tool according to claim 1 includes a main body that is rotated around an axis, and a cutting head that is detachably attached to a tip of the main body and that performs cutting of a workpiece. A convex portion protruding from one surface of the mating surface of the main body portion and the cutting head, and a concave portion recessed from the other surface of the mating surface to receive the convex portion. A key groove provided in one of the inner peripheral surface of the concave portion or the outer peripheral surface of the convex portion, and the inner peripheral surface of the concave portion or the outer peripheral surface of the convex portion to engage with the key groove And a key protruding from the other surface of the first projection, the convex portion having a tapered portion whose outer peripheral surface is inclined with respect to the axial center, and the concave portion having an inner peripheral surface at the tapered portion. A tapered portion having a correspondingly inclined taper hole, wherein the key groove is inclined with respect to the axis. Provided, the inclination direction of the inclined portion is set in a direction to retract said cutting head to said body portion by a cutting resistance during cutting.

  The cutting tool according to claim 2 is the cutting tool according to claim 1, wherein the keyway includes a parallel portion formed substantially parallel to the shaft core, and one end side of the parallel portion is a top portion of the convex portion. Or it is arrange | positioned at the opening part of the said recessed part, and the other end side is connected with the edge part of the said inclination part.

  The cutting tool according to claim 3 is the cutting tool according to claim 1 or 2, wherein an inclination angle at which the inclined portion is inclined with respect to the axis is within a range of approximately 35 degrees or more and approximately 55 degrees or less. Is set.

  The cutting tool according to claim 4 is the cutting tool according to any one of claims 1 to 3, wherein the tapered portion and the tapered hole are set in a range of approximately 1/20 or more and approximately 1/5 or less. Yes.

  The cutting tool according to claim 5 is the cutting tool according to any one of claims 1 to 4, wherein the number of key grooves provided on one of the inner peripheral surface of the concave portion and the outer peripheral surface of the convex portion is provided. Is constituted by one, and one key is arranged at a position corresponding to the key groove.

  The cutting tool according to claim 6 is the cutting tool according to any one of claims 1 to 5, wherein the convex portion protrudes from the cutting head, and the concave portion is provided in the main body portion. Yes.

  According to the cutting tool of claim 1, the convex portion protruding from one surface of the mating surface of the main body portion and the cutting head includes the tapered portion whose outer peripheral surface is inclined with respect to the axis. The concave portion provided in the other surface of the mating surface is provided with a tapered hole whose inner peripheral surface is inclined corresponding to the tapered portion. In addition, a key groove having an inclined portion that is inclined with respect to the axis is recessed in one surface of the outer peripheral surface of the convex portion or the inner peripheral surface of the concave portion, and the outer peripheral surface of the convex portion or the inner periphery of the concave portion. A key for engaging with the keyway protrudes from the other surface. The inclination direction of the inclined portion is set to the direction in which the cutting head is pulled toward the main body due to the cutting resistance at the time of cutting. Therefore, the taper portion and the taper hole are firmly brought into contact with each other, and the cutting head is moved to the main body portion. There is an effect that it can be firmly fixed.

  Moreover, since the cutting head is configured to be detachable from the main body, when the cutting head is consumed, only the cutting head can be replaced. This eliminates the need for exchanging the entire cutting tool, and has the effect of reducing the manufacturing cost.

  In addition, the cutting head and the main body can be made of different materials, that is, only the cutting head can be made of cemented carbide, so the solid cutting tool in which the entire cutting tool is made of cemented carbide. As compared with the above, there is an effect that the material cost and the processing cost can be reduced.

  According to the cutting tool according to claim 2, in addition to the effect of the cutting tool according to claim 1, one end side is arranged at the top of the convex portion or the opening of the concave portion, and the other end side is an end portion of the inclined portion. And a parallel portion that is substantially parallel to the axis. Thereby, compared with the case where a keyway is comprised only by an inclination part, since the full length of a keyway can be shortened, the processing area of a keyway can be reduced and processing cost can be reduced. effective.

  Moreover, since the opening area of the key groove provided in the inner peripheral surface of the concave portion or the outer peripheral surface of the convex portion can be reduced, the wall portion or convex portion forming the concave portion is prevented from being thinned accordingly. And there exists an effect that the rigidity of the wall part or convex part which forms these recessed parts can be ensured.

  According to the cutting tool according to claim 3, in addition to the effect of the cutting tool according to claim 1 or 2, the inclination angle at which the inclined portion is inclined with respect to the axis is approximately 35 degrees or more and approximately 55 degrees or less. It is set within the range. When the inclination angle is smaller than 35 degrees, that is, when the inclined portion is substantially parallel to the shaft core, the axial component force received by the inclined portion from the key is reduced, so that the force for pulling the cutting head toward the main body side is reduced. The cutting head cannot be firmly fixed to the main body.

  On the other hand, when the inclination angle is greater than 55 degrees, that is, when the inclined portion approaches a substantially right angle with the axis, the entire length of the inclined portion must be increased in order to attach the cutting head to the main body portion. The opening area of the groove is increased, the processing cost of the key groove is increased, and the rigidity of the wall portion or the convex portion of the concave portion where the key groove is recessed is lowered.

  From the above, by setting the inclination angle within a range of approximately 35 degrees or more and approximately 55 degrees or less, the cutting head is firmly fixed to the main body portion, while preventing an increase in processing cost and the wall portion or protrusion of the recess. There is an effect that the rigidity of the portion can be maintained.

  According to the cutting tool according to claim 4, in addition to the effect exhibited by the cutting tool according to any one of claims 1 to 3, the taper angle of the tapered portion and the tapered hole is approximately 1/20 or more and approximately 1/5. It is set within the following range. When the taper angle is smaller than 1/20, the axial component of the force acting on the contact surfaces of the taper portion and the taper hole becomes small, so that the taper portion can be made difficult to come out of the taper hole. Since the distance from the base of the convex portion to the top portion and the bottom surface of the concave portion to the opening is required, the area of the tapered surface increases and the manufacturing cost increases.

  On the other hand, when the taper angle is larger than 55 degrees, the area of the taper surface can be reduced and the manufacturing cost can be reduced. However, for the same reason, the taper portion is easily removed from the taper hole.

  From the above, by setting the taper angle within a range of about 1/20 or more and about 1/5 or less, there is an effect that it is possible to achieve both prevention of the taper portion from coming off and reduction in manufacturing cost. .

  According to the cutting tool of the fifth aspect, in addition to the effect produced by the cutting tool according to any one of the first to fourth aspects, the number of key grooves is one, and the number corresponding to the key groove is at a position corresponding to the key groove. One key is arranged. As a result, by increasing the number of key grooves, it is possible to prevent the wall portion and the convex portion forming the concave portion from becoming thin, and to maintain the rigidity of the wall portion and the convex portion forming the concave portion. effective.

  According to the cutting tool of the sixth aspect, in addition to the effect produced by the cutting tool according to any one of the first to fifth aspects, the convex portion protrudes from the cutting head, and the concave portion is recessed in the main body portion. ing. The cutting head needs to be rigid in order to perform cutting by contacting the workpiece during cutting. Therefore, by providing the concave portion in the main body portion, there is an effect that the concave portion of the cutting head is prevented from being thinned and the rigidity of the cutting head can be maintained.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings. FIG. 1 is an exploded view of the cutting tool 1 according to the first embodiment of the present invention, and FIGS. 1A and 1B are front views of the cutting head 2 and the main body 3, respectively. In addition, illustration of the axial direction length of the main-body part 3 is abbreviate | omitted in FIG.1 (b).

  First, the overall configuration of the cutting tool 1 will be described with reference to FIG. The cutting tool 1 includes a cutting head 2 and a main body 3 to which the cutting head 2 is attached. The rotational force of the processing machine transmitted through a holder (not shown) that holds the main body 3. Thus, the cutting head 2 cuts the workpiece.

  According to the cutting tool 1 of the present invention, since the cutting head 2 and the main body 3 are configured to be detachable, the cutting head 2 and the main body 3 are made of different materials, that is, only the cutting head 2 is formed. Since it can be made of cemented carbide, material costs and processing costs can be reduced.

  Further, when only the cutting head 2 is consumed, only the cutting head 2 can be replaced. Therefore, the entire cutting tool 1 is not required to be replaced, and the manufacturing cost can be reduced and the resources can be effectively used. .

  As described above, the cutting head 2 protrudes from the blade portion 24 for cutting the workpiece and the mating surface 21 located at the rear end (right side in FIG. 1A) of the blade portion 24. And a key groove 22 that is recessed in the outer peripheral surface of the convex portion 23. In addition, the cutting head 2 is comprised from the cemented carbide alloy as mentioned above.

  The blade portion 24 has a cutting blade, an oil groove (not shown), and the like engraved on the outer peripheral surface thereof. In this embodiment, the case where the cutting head 2 is a drill will be described. However, the present invention is not limited to this, and the cutting head 2 may be configured as an end mill.

  The convex portion 23 is a portion that becomes a joint portion with the main body portion 3, is protruded from the mating surface 21, and is configured to be able to fit into a concave portion 33 described later. In addition, the convex part 23 is provided with the taper part 23a which the outer peripheral surface reduces in diameter to the main-body part 3 side (FIG. 1 (a) right side), and the plane part 23b substantially parallel to the axial center O, and is comprised. However, you may comprise the taper surface which diameter-reduces the whole outer peripheral surface of the convex part 23 to the main-body part 3 side.

  The taper angle of the taper portion 23a is set within a range of about 1/20 or more and about 1/5 or less. When the taper angle is smaller than 1/20, the component force in the direction of the axis O of the force acting on the contact surfaces of the taper portion 23a and the taper hole 33a, which will be described later, becomes small. Although it can be made difficult to come off from 33a, since the distance from the base part to the top part of the convex part 23 is required, the area of a taper surface increases and manufacturing cost increases.

  On the other hand, when the taper angle is larger than 1/5, the area of the taper surface can be reduced and the manufacturing cost can be reduced. However, for the same reason, the taper portion 23a is easily removed from the taper hole 33a.

  From the above, by setting the taper angle 23a within the range of about 1/20 or more and about 1/5 or less, it is possible to achieve both prevention of the taper portion 23a from falling and reduction in manufacturing cost.

  The key groove 22 is recessed in the outer peripheral surface of the convex part 23, and is comprised so that engagement with the key 32 mentioned later is possible. The key groove 22 includes an inclined portion 22a that is inclined with respect to the axis O, and a parallel portion 22b that extends substantially parallel to the axis O from one end of the inclined portion 22a. ing.

  The inclined portion 22a has an inclination along the rotation direction of the cutting tool 1 (clockwise as viewed from the direction of the arrow X), and the cutting head 2 is on the main body 3 side (right side in FIG. 1A) during cutting. ), The cutting head 2 is pulled toward the main body 3 while the inclined portion 22a and the key 32 are engaged. Thereby, the taper part 23a and the taper hole 33a mentioned later can be firmly contacted, and the cutting head 2 can be firmly fixed to the main body part 3.

  The inclination angle at which the inclined portion 22a is inclined with respect to the axis O is set in a range of approximately 35 degrees or more and approximately 55 degrees or less. When the inclination angle is smaller than 35 degrees, that is, when the inclined portion 22a approaches substantially parallel to the axis O, the axial component force received by the inclined portion 22a from the key 32 decreases, so that the cutting head 2 is attached to the main body portion. The force to be pulled to the side 3 is reduced, and the cutting head 2 cannot be firmly fixed to the main body 3.

  On the other hand, when the tilt angle is greater than 55 degrees, that is, when the tilted portion 22a approaches a substantially right angle with the axis O and the protruding position of the key 32 is constant, the cutting head 2 is attached to the main body portion 3. Therefore, since the entire length of the inclined portion 22a has to be increased as compared with the case where the inclination angle is small, the opening area of the key groove 22 is increased, the processing cost of the key groove 22 is increased, and the key groove 22 is increased. As a result, the rigidity of the convex portion 23 in which the concave portion is provided is lowered.

  From the above, the cutting head 2 is firmly fixed to the main body 3 by setting the inclination angle at which the inclined portion 22a is inclined with respect to the axis O within a range of approximately 35 degrees or more and approximately 55 degrees or less. However, it is possible to prevent the processing cost from increasing and maintain the rigidity of the convex portion 23.

  In addition, one end of the inclined portion 22a is provided with a parallel portion 22b extending substantially parallel to the axis O. Thereby, compared with the case where the key groove 22 is comprised only by the inclination part 22a, since the full length of the key groove 22 can be shortened, the processing area of the key groove 22 is reduced and processing cost is reduced. be able to.

  Moreover, since the opening area of the keyway 22 recessed in the outer peripheral surface of the convex part 23 can be reduced, the convex part 23 is prevented from becoming thin by that much, and the rigidity of the convex part 23 is ensured. can do.

  As described above, the main body 3 has a recess 33 that can be fitted to the protrusion 23, a wall 34 that stands on the outer periphery of the recess 33, and a hole that is formed in the wall 34. The key 32 is configured to mainly include a key 32 that can be inserted and engaged with the key groove 22. In addition, the main-body part 3 is comprised from the high speed tool steel.

  The concave portion 33 is a portion that becomes a joint portion with the cutting head 2, and includes a tapered hole 33a having an inclination corresponding to the tapered portion 23a, and a flat portion 33b substantially parallel to the axis O. .

  Further, the distance dimension from the bottom surface of the concave portion 33 to the opening is set larger than the distance dimension from the base portion to the top portion of the convex portion 22. Thereby, when the cutting head 2 is attached to the main body 3, a gap is formed between the mating surface 21 of the cutting head 2 and the mating surface 31 of the main body 3. Thereby, when the cutting head 2 is drawn into the main body 3 by cutting resistance, a space for the drawing can be secured.

  The distance dimension from the bottom surface of the concave portion 33 to the opening may be configured to be substantially the same as the distance dimension from the base portion to the top portion of the convex portion 22. In this case, the mating surface 21 of the cutting head 2 and the mating surface 31 of the main body 3 come into contact with each other. Accordingly, the cutting head 2 can be attached to the cutting head 2 and the main body 3 with the two taper surfaces of the taper portion 22a and the taper hole 33a and the mating surfaces 21 and 31. Can be fixed to.

  The key 32 protrudes from the inner peripheral surface of the recess 33 and is configured to be engageable with the key groove 22.

  Next, the cutting head 2 will be described with reference to FIG. FIG. 2 is a rear end view of the cutting head 2 as seen from the direction of the arrow X in FIG.

  On the rear end surface of the cutting head 2, as shown in FIG. 2, one key groove 22 is recessed toward the axis O. As described above, the key groove 22 is a part engaged with the key 32 (see FIG. 1), and the depth dimension of the key groove 22 is set to be approximately equal to or higher than the height dimension of the key 32. Yes.

  In the present embodiment, the number of the key grooves 22 is one, but the number of the key grooves 22 is two, and the key grooves 22 may be arranged at substantially equal intervals in the circumferential direction (180 ° intervals). good. By disposing two key grooves 22, it is possible to increase the force with which the cutting head 2 is pulled into the main body 3 (see FIG. 1) by cutting resistance.

  However, when the number of key grooves 22 is three or more, the convex portion 23 becomes thin and the rigidity of the convex portion 23 decreases. Moreover, since the processing cost for processing the key groove 22 increases, it is desirable that the key groove 22 is composed of two or less.

  Next, the main body 3 will be described with reference to FIG. 3A is a front end view of the main body 3 viewed from the direction of arrow Y in FIG. 1, and FIG. 3B is a cross-sectional view of the main body 3 taken along the line IIIb-IIIb in FIG. It is.

  As shown in FIG. 3 (a), one key 32 protrudes toward the axis O on the inner peripheral surface of the recess 33 that is provided in the distal end surface of the main body 3. As described above, the key 32 is a part engaged with the key groove 22 (see FIG. 1).

  In addition, although the key 32 is formed in a substantially circular shape, for example, a substantially elliptical shape or a polygonal shape may be used. That is, when the key 32 is engaged with the key groove 22, the side surface of the key 32 and the side surface of the key groove 22 are in contact with each other, and the contact surfaces may be movable.

  As shown in FIG. 3B, the key 32 protrudes from the flat portion 33b. However, when the key groove 22 extends to the tapered portion 23a, the key 32 protrudes from the tapered hole 33a. It may be configured. That is, when the cutting head 2 (see FIG. 1) is attached to the main body 3, the key 32 may be disposed at a position where the key 32 can be engaged with the inclined portion 22a (see FIG. 1).

  Next, a second embodiment will be described with reference to FIG. In the first embodiment, the case where the key groove 22 provided in the convex portion 23 of the cutting head 2 is engaged with the key 32 provided in the concave portion 33 of the main body 3 has been described. In the embodiment, the key 122 protruding from the convex portion 23 of the cutting head 102 engages with the key groove 132 provided in the concave portion 33 of the main body portion 103. In addition, the same code | symbol is attached | subjected to the part same as above-described 1st Embodiment, and the description is abbreviate | omitted.

  FIG. 4 is an exploded view of the cutting tool 101 according to the second embodiment, and FIGS. 4A and 4B are front views of the cutting head 102 and the main body 103, respectively. In FIG. 4B, illustration of the axial length of the main body 103 is omitted.

  As shown in FIG. 4A, the key 122 protrudes from the outer peripheral surface of the convex portion 23 and is configured to be engageable with a key groove 132 described later.

  As shown in FIG. 4B, the key groove 132 is recessed on the inner peripheral surface of the recess 33 and is configured to be engageable with the key 122. The keyway 132 includes an inclined portion 132a that is inclined with respect to the axis O, and a parallel portion 132b that extends substantially parallel to the axis O from one end of the inclined portion 132a. ing.

  The inclined portion 132a has an inclination along the rear side of the cutting tool 101 in the rotation direction (clockwise as viewed from the arrow X direction), and the cutting head 102 is on the main body 103 side (FIG. 4B) during cutting. In order to receive the component force in the direction of the axis O of the cutting force to the right side), the cutting head 102 is pulled toward the main body 103 while the inclined portion 132a and the key 122 are engaged. Thereby, the taper part 23a and the taper hole 33a can be firmly contacted, and the cutting head 102 can be firmly fixed to the main body part 103.

  The present invention has been described above based on the embodiments. However, the present invention is not limited to the above embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention. Can be easily guessed.

  For example, in each of the above-described embodiments, the convex portion 23 protruding from the rear end surface of the cutting heads 2 and 102 is configured to be able to be fitted to the concave portion 33 concaved at the front end surfaces of the main body portions 3 and 103. However, the present invention is not necessarily limited to this. For example, the concave portion provided in the rear end surface of the cutting head 2, 102 is fitted with the convex portion provided in the front end surface of the main body portions 3, 103. It may be configured to be compatible.

  However, since the cutting heads 2 and 102 are parts for cutting, rigidity is required. For this reason, it is preferable to provide a projecting portion to ensure the rigidity of the cutting head 2 and 102 rather than to provide a recessed portion in the cutting head 2 and 102.

  In addition, the case where the cutting heads 2 and 102 are made of cemented carbide and the main body portions 3 and 103 are made of high-speed tool steel has been described. However, the present invention is not necessarily limited to this. While 102 is comprised from high speed tool steel, you may comprise the main-body parts 3 and 103 from alloy tool steel.

BRIEF DESCRIPTION OF THE DRAWINGS It is an exploded view of the cutting tool in 1st Embodiment of this invention, (a), (b) is a front view of a cutting head and a main-body part, respectively. FIG. 2 is a rear end view of the cutting head as viewed from the direction of arrow X in FIG. 1. (A) is a front end view of the main body viewed from the direction of arrow Y in FIG. 1, and (b) is a cross-sectional view of the main body taken along line IIIb-IIIb in FIG. 3 (a). (A) And (b) is a front view of the cutting head and main-body part in 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,101 Cutting tool 2,102 Cutting head 3,103 Main-body part 21,31 Matching surface 22,132 Keyway 22a, 132a Inclined part 22b, 132b Parallel part 23 Convex part 23a Taper part 32,122 Key 33 Concave part 33a Tapered hole

Claims (6)

In a cutting tool comprising a main body rotated around an axis, and a cutting head that is detachably attached to the tip of the main body to cut a workpiece,
A convex portion projecting from one surface of the mating surface of the main body portion and the cutting head, a concave portion recessed in the other surface of the mating surface to accept the convex portion, and an inner periphery of the concave portion A key groove recessed in one surface of the surface or the outer peripheral surface of the convex portion, and projecting from the inner peripheral surface of the concave portion or the other surface of the outer peripheral surface of the convex portion to engage with the key groove With a key to be
The convex portion includes a tapered portion whose outer peripheral surface is inclined with respect to the shaft core, and the concave portion includes a tapered hole whose inner peripheral surface is inclined corresponding to the tapered portion,
The keyway includes an inclined portion having an inclination with respect to the shaft core, and an inclination direction of the inclined portion is set to a direction in which the cutting head is drawn toward the main body portion by a cutting resistance at the time of cutting. A cutting tool characterized by that.   The key groove includes a parallel portion formed substantially parallel to the shaft core, and one end side of the parallel portion is disposed at the top of the convex portion or the opening of the concave portion, and the other end side is inclined. The cutting tool according to claim 1, wherein the cutting tool is connected to an end of the portion.   The cutting tool according to claim 1 or 2, wherein an inclination angle at which the inclined portion is inclined with respect to the axis is set in a range of approximately 35 degrees or more and approximately 55 degrees or less.   4. The cutting tool according to claim 1, wherein taper angles of the tapered portion and the tapered hole are set in a range of approximately 1/20 or more and approximately 1/5 or less. 5. The number of key grooves that are recessed in one surface of the inner peripheral surface of the concave portion or the outer peripheral surface of the convex portion is composed of one,
The cutting tool according to claim 1, wherein one key is arranged at a position corresponding to the key groove.   The cutting tool according to claim 1, wherein the convex portion protrudes from the cutting head, and the concave portion is recessed in the main body portion.

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