JP2007276083A - Pin mirror cutter and cutting edge replacing tip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve service life balance between parts of a cutting edge of an edge replacing tip of a pin mirror cutter so as to reduce the tool costs in the machining cost and also to reduce the labor for replacing the tip. <P>SOLUTION: The pin mirror cutter is formed by installing a first cutting edge replacing tip 1 and a second cutting edge replacing tip formed into the similar specification to a cutter main body 11, and the first cutting edge replacing tip 1 machines the periphery of a pin part of a crank shaft and a pin R part, and the second cutting edge replacing tip 2 machines a shoulder R part of the crank shaft. A third cutting edge replacing tip 3 formed into a square in the upper and the lower surfaces is added to the pin mirror cutter so as to machine the pin R part of the crank shaft with two of an imperfect R cutting edge 3e provided in each corner of the third cutting edge replacing tip 3 and a first cutting edge 1c of the first edge replacing tip 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pin mirror cutter for processing a crankshaft and a cutting edge replacement tip employed in the cutter.

  As conventional examples of the pin mirror cutter mentioned above, for example, there are those disclosed in Patent Documents 1 and 2 below.

  In Patent Document 1, a parallelogram chip (referred to as chip A for convenience) having an arcuate cutting edge at an acute corner portion and an incomplete R cutting edge at an obtuse corner portion is provided on the peripheral surface of the cutter body. A square tip (referred to as tip B) with an arcuate cutting edge at each corner is mounted on the seat on each side seat of the cutter body, and further on another seat on the peripheral surface of the cutter body. A chip with the same specifications as A (referred to as chip C) is positioned so that the positions of the obtuse corner part and the acute angle corner part are interchanged with those of the chip A, and the obtuse angle corner part is more than the cutter axial end of the chip A. The pin R portion 32 of the crankshaft 30 as shown in FIG. 16 is inserted with the arcuate cutting edge of the tip A and the incomplete R cutting edge of the tip C, and the shoulder R portion 33 is inserted. With the arcuate cutting edge of B, Cutter for cutting each outer periphery of the emission portion 31 in a straight line cutting edge of the chip A and chip C is shown (hatched portion main machining allowance in FIG 16 (a)).

  Further, Patent Document 2 discloses a plate-like chip in which arc-shaped first and second cutting edges are respectively formed on the acute and obtuse corner portions of the upper and lower surfaces of the parallelogram, and the peripheral surface of the cutter body. Mounted on seats on both sides, the first cutting edge of the tip mounted on the seat on the circumferential surface, the crankshaft pin R part, the long side cutting edge the crankshaft pin outer periphery, the side seat The cutter which cuts the shoulder R part of a crankshaft with the 2nd cutting edge of the chip | tip mounted | worn to each is shown.

Here, the cutter of Patent Document 2 tries to improve the economic effect by processing each part of the crankshaft with a common tip whose posture is changed, but in reality, the pin R part of the crankshaft is processed. Since the cutting load of the first cutting edge is larger than the cutting load of the second cutting edge that processes the shoulder R portion, the insert of the first cutting edge must be replaced before the second cutting edge reaches the end of its life. Therefore, the economic effect directly linked to the processing cost could not be sufficiently increased.
In order to solve this problem, it is only necessary to increase the number of blade rows of the chips arranged on the peripheral surface side, but it is difficult to increase the number of blade rows because of empty space. Therefore, as shown in FIG. 17, the long side of the tip 21 having a substantially parallelogram is positioned on the side surface, and the sharp corner is positioned on the pin R portion 32. It is conceivable to increase the number of chips for processing the edge. However, in this structure, the second cutting edge for processing the shoulder R portion 33 is unused, resulting in an increase in running cost.

  The cutter of Patent Document 1 has the same problem. The cutter of this Patent Document 1 was developed for the purpose of increasing the life balance of each cutting edge, and the pin R portion of the crankshaft has an acute corner portion of the tip A and a tip C (that is, the tip A). However, in this structure, the same pin R part is machined at the acute corner part and the obtuse corner part having the same chip shape, so that the sharp corner part and the obtuse corner part are Variations in the service life occur (especially, the sharp corner portion that handles the outer end of the pin R portion is easily damaged), and the corners of the chips A and C cannot be used effectively.

Moreover, since the shape of the blades of the acute corner part and the obtuse corner part that machine the pin R part are not the same, it cannot be said that the number of effective blades of the part that machine the pin R part has increased, and the rotational speed of the cutter is It was not possible to meet the demand to increase the processing efficiency.
Japanese Utility Model Publication No.59-12519 Japanese Patent Laid-Open No. 5-42409

  This invention increases the life balance of each part of the cutting edge of the cutting edge replacement tip in the pin mirror cutter in order to reduce the tool cost occupying the processing cost and the time for changing the tip. The challenge is to be able to respond.

In order to solve the above-described problems, in the present invention, a pin mirror cutter using a cutting edge replacement tip is configured as follows. That is,
A rake face and two faces (referred to as upper and lower faces in the present invention) have a first cutting edge that forms an arc at an acute corner portion of a substantially parallelogram tip, and a second cutting edge that forms an arc at an obtuse corner portion. Each of the blades is further formed, and two first long cutting edges parallel to each other and two short cutting edges parallel to each other are formed on the edges of the upper and lower surfaces. The two cutting edge replacement tips and the two rake surfaces (also referred to as the upper and lower surfaces) have a common radius with an R radius equal to the R radius of the first cutting edge at each corner of the substantially square tip. A third cutting edge replacement tip having a complete R cutting edge was provided.
The first cutting edge replacement tip has a rake face on one of the upper and lower surfaces, the first cutting edge is on the cutter shaft direction outer end, and the long side cutting edge is on the peripheral surface side of the cutter. Mounted on a seat provided on the peripheral surface of the cutter body in a position to be arranged, and the second cutting edge replacement tip has a rake face on either the upper or lower surface and the second cutting edge is the cutter. The third cutting edge replacement tip has a rake face on one of the upper and lower surfaces, and one corner part involved in cutting is formed on the seat provided on both side surfaces of the cutter body. The first cutting edge replacement tip enters from the end in the cutter axial direction, and the locus of the incomplete R cutting edge of the corner portion is on the locus of the first cutting edge of the first cutting edge replacement tip. The cutter is arranged in an overlapping manner (the traces of the R centers of both cutting edges overlap) Respectively mounted on the seat provided on both sides of the body,
The outer periphery of the crankshaft pin portion is cut by the long side cutting edge of the first cutting edge replacement tip, and the crankshaft is formed by the first cutting edge of the first cutting edge replacement tip and the incomplete R cutting edge of the third cutting edge replacement tip. The pin R portion was cut with the shoulder R portion of the crankshaft by the second cutting edge of the second cutting edge replacement tip.

Preferred forms of this pin mirror cutter are listed below.
(1) The third cutting edge replacement tip is attached with an inclination of 2 to 4 ° in the cutter axial direction so that the peripheral edge of the cutter can escape.
(2) The amount δ of the third cutting edge replacement tip entering from the end of the first cutting edge replacement tip to the inside in the cutter axial direction is set to 0.2 to 0.4 mm.
(3) The same number of first to third cutting edge replacement tips are mounted on the cutter body.
(4) The third cutting edge replacement tip is provided with two parallel long side ridge lines and two parallel short side ridge lines between the incomplete R cutting edges of each corner, and the top and bottom surfaces are substantially rectangular chips. Then, the third cutting edge replacement tip is mounted on the seat in such a posture that the short side ridge line is arranged on the peripheral surface side of the cutter body.

  In the third cutting edge replacement tip, an incomplete R cutting edge having a predetermined radius of curvature is formed at each corner portion of a tip having a rectangular top and bottom surface, and further, two mutually parallel long side ridge lines and two mutually Parallel short-side ridge lines are formed at the edges of the top and bottom surfaces, and the shape is symmetrical with respect to a line that intersects one short side of the top and bottom surfaces and the other short side at right angles to the long-side ridge line. Is preferred. The present invention also provides such a blade edge replacement tip in combination with the pin mirror cutter.

  The incomplete R cutting edge referred to in the present invention means that the tangent line at one end of the arcuate cutting edge is less than 180 ° with respect to one of the two ridge lines forming the corner. A blade connected at an angle.

  The pin mirror cutter of the present invention can be considered to be obtained by adding a third cutting edge replacement tip to the cutter disclosed in Patent Document 2 described above. By adding the third cutting edge replacement tip, the machining of the pin R portion of the crankshaft that dominates the tool life is performed by the first cutting edge replacement tip and the third cutting edge replacement tip. The burden on the cutting edge for machining the part is almost halved compared to the case where the pin R part is machined with a single cutting edge. As a result, the life of the cutting edge for processing the pin R portion is improved, the life difference between the corners is reduced, and tip replacement in a state where some of the cutting edges are still usable can be avoided.

  In addition, by adopting the third blade tip replacement tip, the number of effective blades in the pin R portion is increased as compared with the cutter of Patent Document 2 described above. Not only the pin mirror cutter but also the milling cutter is an effective method for performing high-efficiency machining by increasing the number of blades, so that the machining efficiency can be improved by increasing the number of blades.

  Note that the third cutting edge replacement tip has an unused cutting edge (in the cutter axis direction) of the two incomplete R cutting edges placed on the peripheral surface of the cutter when the inclination angle in the cutter axis direction is 0 °. Since a part of the incomplete R cutting edge on the inside is damaged due to cutting, it is better not to use the cutting edge that is not used for cutting. And the request | requirement can be satisfy | filled by inclining in the direction which escapes to the cutter peripheral surface side. However, since this third cutting edge replacement tip has a square top and bottom surface, it is inclined in the cutter axis direction so that the cutting edge of the corner portion becomes a quarter circle, and the locus between the first cutting edge and the R center is changed. If they are placed so as to overlap, it is not possible to escape from the side. In order to eliminate the problem, the cutting edge of the corner portion was made into an incomplete R cutting edge, and the corner portion was further inserted δ from the end in the cutter axis direction of the first cutting edge replacement tip into the cutter axis direction inside.

  The inclination angle of the third blade edge replacement tip in the cutter axis direction is set to 2 to 4 °, and the amount δ of the first blade edge replacement tip entering from the end of the first blade edge replacement tip into the cutter axis direction is set to about 0.2 to 0.4 mm. It is preferable. If the inclination angle in the cutter axis direction of the third cutting edge replacement tip is too large, the corner entry amount δ has to be increased, and the area where the first cutting edge replacement tip is processed independently increases, resulting in the first cutting edge replacement. If the work amount of the tip increases, but the inclination angle of the third blade tip replacement tip and the amount of entering the corner portion are within the above ranges, the first cutting edge and the third blade tip replacement of the first blade tip replacement tip The difference in the work of the incomplete R cutting edge of the insert and the life difference due to the difference in the work are not so large.

  In addition, the same number of the first to third blade edge replacement tips is mounted, the life of the first to third blade edge replacement tips is averaged, and the replacement work is performed at the same replacement time. Efficiency can be improved.

  Further, as the third cutting edge replacement tip, a tip having a substantially rectangular top and bottom surface, in particular, a line that intersects one short side of the top and bottom surfaces and the other short side at right angles to the long side ridge line is used as a reference. When the tip having a line symmetry shape is mounted on the seat in a posture in which the short side is arranged on the peripheral surface side of the cutter body, it is easy to ensure the support stability of the third blade tip replacement tip.

  Embodiments of the pin mirror cutter according to the present invention will be described below with reference to FIGS. The illustrated cutter 10 is an internal pin mirror cutter, and is configured by attaching first to third blade edge replacement tips 1, 2, and 3 to an annular cutter body 11. Each blade edge replacement tip 1 to 3 is fixed by the clamp screw 4, but may be fixed by a clamping means other than the clamp screw if there is no restriction on the space.

  The cutter body 11 is used by being fitted to the inner diameter side of an adapter (not shown). As shown in FIGS. 1 to 3, on the inner peripheral surface of the cutter body 11, a seat 12 </ b> R that opens to one side with the inner peripheral surface and a seat 12 </ b> L that opens to the inner peripheral surface and the other side face in the cutter circumferential direction. A staggered arrangement is provided, and seats 13R and 13L and seats 14R and 14L are provided in a staggered arrangement in the circumferential direction of the cutter on one side and the other side of the cutter body 11, respectively.

  Each of the first to third cutting edge replacement tips 1 to 3 is a plate-like negative tip in which the dimension between the upper and lower surfaces (the dimension in the direction directed to the cutter rotating direction during use) is larger than the thickness dimension.

As shown in FIGS. 7 to 10, the first cutting edge replacement tip 1 has an arcuate first cutting edge 1 c at the acute corner portion of the tip in which the parallelly arranged upper surface 1 a and lower surface 1 b form a parallelogram. Arc-shaped second cutting edges 1d are respectively formed at the obtuse corner portions, and one set of two parallel edges of the upper surface 1a and the lower surface 1b is the long side cutting edge 1e and the other set of parallel Two sides are formed as a short side cutting edge 1f, and a mounting hole 5 through which the clamp screw 4 is passed is provided at the center between the upper and lower surfaces. For convenience of explanation, the upper surface 1a and the lower surface 1b are one surface as the upper surface and the other as the lower surface. However, the upper surface 1a and the lower surface 1b are common surfaces that can be replaced with each other by inverting the chip.
The second cutting edge 1d has an incomplete R-cut where the tangent (tL in FIG. 10) at the end on the short-side cutting edge 1f side is connected to the short-side cutting edge 1f at an angle of less than 180 °. The blade can secure the length of the short-side cutting edge 1f to be long and improve the seating stability of the chip, and it is also easy to distinguish between the first cutting edge 1c and the second cutting edge 1d. Therefore, the illustrated blade has an incomplete R cutting edge.

  The second cutting edge replacement tip 2 is a tip having the same specifications as the first cutting edge replacement tip 1. Therefore, the same reference numeral 1d as that of the second cutting edge of the first cutting edge replacement tip 1 is attached to the second cutting edge, and description of this tip is omitted.

  As shown in FIGS. 11 to 13, the third cutting edge replacement tip 3 is formed with incomplete R cutting edges 3 e at each corner portion of a tip having an upper surface 3 a and a lower surface 3 b that are rectangular. A parallel long side ridge line 3c and two parallel short side ridge lines 3d are formed at the edges of the upper and lower surfaces, and a mounting hole 6 through which the clamp screw 4 is passed is provided at the center between the upper and lower surfaces. The incomplete R cutting edge 3e formed in each corner is a cutting edge having a common shape whose position can be changed by a corner change of the chip. The incomplete R cutting edge 3e has an R radius equal to the R radius of the first cutting edge 1c described above. Here, the tangent tL at the end on the long side ridge line 3c side is an incomplete R cutting edge connected at an angle of less than 180 ° with respect to the long side ridge line 3c, and the upper and lower surfaces 3a, 3b A side surface of a plane along the long side ridge line 3c, with one short side and the other short side symmetric with respect to a line (L in FIG. 13) intersecting at right angles to the long side ridge line 3c. The area of is expanded as much as possible. The third cutting edge replacement tip 3 may have a square upper and lower surface as long as the clamping allowance can be secured.

  In the pin mirror cutter shown in FIGS. 1 to 5, the first cutting edge replacement tip 1 has a top face or a bottom face as a rake face, and the first cutting edge 1c is at the outer end in the cutter axial direction. The cutting edges 1e are respectively arranged on the peripheral surface side of the cutter and are mounted on the seats 12L and 12R.

  Further, the second cutting edge replacement tip 2 has seats 14R, 14L provided on both side surfaces of the cutter body 11 with the upper or lower surface being raked and the second cutting edge 1d protruding to the side of the cutter. Furthermore, the third cutting edge replacement tip 3 has a rake face on the upper surface or the lower surface, and one corner portion is located on the inner side in the cutter axial direction from the cutter axial end of the first cutting edge replacement tip 1. 5 and the locus of the incomplete R cutting edge 3e at the corner portion is on the locus of the first cutting edge 1c of the first cutting edge replacement tip as shown in FIG. The seats 13R and 13L provided on both side surfaces of the cutter body in an overlapping arrangement are mounted.

  Since the third cutting edge replacement tip 3 is inclined in a direction in which both the side surface and the inner peripheral surface have a clearance angle, the radial rake γf shown in FIG. 1 and the axial rake γp shown in FIG. 2 are both negative. It becomes an angle.

  The 1st-3rd blade edge | tip replacement | exchange chip | tips 1-3 have a corner (I-IV of FIG. 10, FIG. 13) which can use all as a cutting blade in a total of 8 corners on the left-right upper and lower surfaces. Of these eight corners, the first cutting edge replacement tip 1 has a first cutting edge 1c of an acute corner portion and a long side cutting edge 1e (corner I or II) following the cutting edge. The second cutting edge replacement tip 2 is one of the second cutting edges 1d (corner III or IV) formed in the obtuse corner portion, and the third cutting edge replacement tip 3 is incompletely provided in each corner portion. One of the R cutting edges 3e (corners I to IV) is involved in cutting. Therefore, the life balance of these blades can be maintained, and replacement of the damaged blades with unused blades by corner change can be performed at the same time to use the chips without waste.

  In the illustrated cutter, the same number of first to third blade edge replacement tips 1 to 3 are mounted, and the first to third blade edge replacement chips 1 to 3 are moved from the front of the cutter in the rotational direction to the rear in the rotational direction. The arrangement pattern of the first cutting edge replacement tip 1, the third cutting edge replacement tip 3, and the second cutting edge replacement tip 2 is repeated several times during one round toward the end, and the replacement timing of all the tips is also unified. can do.

  FIG. 6 shows the cutting area of the crankshaft (work material) by the first to third cutting edge replacement tips. As can be seen from FIG. 6, the outer periphery of the pin portion 31 of the crankshaft is only the long side cutting edge 1e of the first cutting edge replacement tip, and the shoulder R portion 33 is the second cutting edge of the second cutting edge replacement tip. Each is processed only by 1d. On the other hand, the pin R portion 32 is processed by two members, the first cutting edge 1c of the first cutting edge replacement tip and the incomplete R cutting edge 3e of the third cutting edge replacement tip, whose tracks overlap each other. The load on the cutting edge for machining the portion 32 is reduced. Therefore, the life of each cutting edge is averaged, and the cutting edge of each part of the chip can be used economically.

  The flat wall surface 34 between the pin R portion 32 and the shoulder R portion 33 is processed by the first cutting edge 1c of the first cutting edge replacement tip that is cut in the direction of the arrow in FIG. The inclination angle θ in the cutter axis direction shown in FIG. 5 is 2 to 4 °, and the inflow amount δ from the end portion of the first cutting edge replacement tip (end portion of the first cutting edge 1c) into the cutter axis direction is 0. When set to about 2 to 0.4 mm, it is possible to reliably avoid the third cutting edge replacement tip from interfering with the wall surface 34 in the processing of a general crankshaft. The difference in work amount between the cutting edge 1c of 1 and the incomplete R cutting edge 3e of the third cutting edge replacement tip is not so large.

  14 and 15 show a modification of the third cutting edge replacement tip 3. The short side surface (surface on which the short side ridge line 3d is formed between the upper and lower surfaces) of the third cutting edge replacement tip 3 is limited to the plane shown in FIG. 11 having an angle of 90 ° with the long side ridge line. Not. As shown in FIG. 14, two flat surfaces are concave in a V shape formed by intersecting at an angle of α1 = 160 to 175 °, preferably at the center of the short side ridgeline 3d, or as shown in FIG. Further, a convex surface protruding in a V shape formed by intersecting two planes at the center of the short side ridge line 3d, preferably at an angle of α2 = 172 to 176 °, may be considered. When the side surface of the short side is set to such a surface and seated on the corresponding seating surface, the holding stability of the chip is enhanced.

  Although the above description has been given by taking the internal pin mirror cutter as an example, the present invention can also be applied to an external pin mirror cutter in which the blade tip replacement tip is mounted on the outer periphery of the cutter body.

Side view showing a part of an example of the pin mirror cutter of the present invention The figure which shows the internal peripheral surface of the pin mirror cutter of FIG. The figure which shows the outer peripheral surface of the pin mirror cutter of FIG. 1 is a perspective view of the pin mirror cutter of FIG. Blade row diagram of the pin mirror cutter of FIG. The figure which shows the cutting area by the pin mirror cutter of FIG. Plan view of the first cutting edge replacement tip Side view of the blade tip replacement tip of FIG. 7 is a perspective view of the blade tip replacement tip of FIG. The figure which shows the cutting-edge corner of the blade-tip exchange tip of FIG. Plan view of the third cutting edge replacement tip Side view of the blade tip replacement tip of FIG. The figure which shows the cutting-edge corner of the blade-tip exchange tip of FIG. The top view which shows a part of modification of a 3rd blade edge | tip replacement | exchange tip The top view which shows a part of other modification of the 3rd blade edge | tip replacement | exchange tip (A) Side view of main part of crankshaft, (b) Sectional view of line XX in (a) Blade row diagram of a pin mirror cutter with an increased number of chips for processing the outer edge of the pin R section

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st blade edge | tip replacement tip 1a Upper surface 1b Lower surface 1c 1st cutting edge 1d 2nd cutting blade 1e Long side edge 1f Short edge side cutting edge 2 2nd blade edge replacement tip 3 3rd blade edge replacement tip 3a Upper surface 3b Lower surface 3c Long side ridge line 3d Short side ridge line 3e Incomplete R cutting edge 4 Clamp screw 5, 6 Mounting hole 10 Pin mirror cutter 11 Cutter body 12R, 12L Seat 13R, 13L Seat 14R, 14L Seat 21 Tip 30 Crank Shaft 31 Pin portion 32 Pin R portion 33 Shoulder R portion Wall surface I to IV Cutting edge corner L Reference line tL Tangent θ Axial tilt angle δ Depth of penetration γf Radial rake γp Axial rake α1, α2 Crossing angle

Claims (7)

An arc-shaped first cutting edge (1c) is formed at an acute corner portion of a chip whose upper and lower surfaces (1a, 1b) form a substantially parallelogram, and an arc-shaped second cutting edge (1d) is formed at an obtuse corner portion. In addition, two parallel long-side cutting edges (1e) and two parallel short-side cutting edges (1f) are formed on the edges of the upper and lower surfaces (1a, 1b). 1 cutting edge replacement tip (1) and second cutting edge replacement tip (2),
In addition, a common incomplete R cutting edge (3e) having an R radius equal to the R radius of the first cutting edge (1c) is formed in each corner portion of the chip whose upper and lower surfaces (3a, 3b) form a substantially square shape. The third cutting edge replacement tip (3),
The first cutting edge replacement tip (1) has one of the upper and lower surfaces (1a, 1b) as a rake face, and the first cutting edge (1c) is at the outer end in the cutter axial direction. The cutting blades (1e) are respectively arranged on the peripheral surface side of the cutter and mounted on seats (12R, 12L) provided on the peripheral surface of the cutter body (11),
The second cutting edge replacement tip is provided on both sides of the cutter body (11) with either one of the upper and lower surfaces being raked and the second cutting edge (1d) projecting to the side of the cutter. Mounted on the seat (14R, 14L),
The third cutting edge replacement tip has either one of the upper and lower surfaces (3a, 3b) as a rake surface, and one corner part involved in cutting is a cutter shaft of the first cutting edge replacement tip (1). From the end in the direction of the cutter axis, and the locus of the incomplete R cutting edge (3e) at the corner overlaps the locus of the first cutting edge (1c) of the first cutting edge replacement tip. Mounted on seats (13R, 13L) provided on both sides of the cutter body,
The outer edge of the crankshaft pin portion with the long side cutting edge (1e) of the first cutting edge replacement tip, and the first cutting edge (1c) of the first cutting edge replacement chip and the third cutting edge replacement chip are incomplete. A pin mirror cutter configured to cut the pin R portion of the crankshaft with the R cutting edge (3e) and the shoulder R portion of the crankshaft with the second cutting edge (1d) of the second cutting edge replacement tip.   2. The pin mirror cutter according to claim 1, wherein the third cutting edge replacement tip (3) is attached with an inclination of 2 to 4 ° in the cutter axial direction so that the peripheral surface side of the cutter can escape. 3.   The intrusion amount δ of the third blade edge replacement tip (3) from the end of the first blade edge replacement tip (1) to the inside in the cutter axial direction is set to 0.2 to 0.4 mm. Pin mirror cutter described in 1.   The pin mirror cutter according to any one of claims 1 to 3, wherein the number of the first to third blade edge replacement tips (1, 2, 3) attached to the cutter body is the same.   The third cutting edge replacement tip (3) is a tip whose upper and lower surfaces (3a, 3b) are rectangular in shape, and the third cutting edge replacement tip (3) is arranged on the peripheral surface side of the cutter body on the short side. The pin mirror cutter according to any one of claims 1 to 4, wherein the pin mirror cutter is mounted on the seat (13R, 13L) in a posture.   An incomplete R cutting edge (3e) having a predetermined radius of curvature is formed at each corner portion of a chip whose upper and lower surfaces (3a, 3b) form a rectangle, and two parallel long side ridge lines (3c) Two mutually parallel short side ridge lines (3d) are formed at the edges of the upper and lower surfaces (3a, 3b), and one short side and the other short side of the upper and lower surfaces (3a, 3b) are the long side. A blade tip replacement tip for a pin mirror cutter that is symmetrical with respect to a line (L) that intersects at right angles to the ridge line (3c).   A plane having an angle of 90 ° with the long side ridge line (3c) and a short side surface that generates the short side ridge line (3d) at the intersection with the upper and lower surfaces (3a, 3b) are two planes. Either a V-shaped concave surface formed by intersecting at the center of the short side ridge line (3d) or a convex surface protruding in a V shape formed by two planes intersecting at the center of the short side ridge line (3d) A cutting edge replacement tip for a pin mirror cutter according to claim 6, which is formed as described above.

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