JP2010032037A - Self-tapping insert - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a self-tapping insert, capable of largely taking a cutting blade part and very smoothly removing chips generated by self-tapping to remarkably improve the work efficiency. <P>SOLUTION: In this self-tapping insert 1, cutting blade part forming recessed parts 10 are located at the forward end side and provided in two or more portions equally in the outer peripheral direction. The cutting blade part forming recessed parts 10 each have a section A, which is positioned within a vertical plane (Z-Z plane) passing a position (a) at a predetermined distance (N1) in the direction of an axis O1-O2 from the end face 5 of a tapered tip part 4 and making an angle α1 to the axis O1-O2 in the direction of the end face 5 of the tapered tip part 4, and cut from the outer peripheral surface 2 toward the inner peripheral surface 3, and form a cutting blade part serving as a tapping function. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a self-tapping insert that is an insert nut having a self-tapping function.

  Conventionally, in order to prevent problems such as wear, breakage, seizure, and galling of internal threads when the base material is light alloy, non-ferrous metal, various plastics, etc. Inserts are widely used.

  That is, for example, as described in Reference 1, the helical coil insert is usually made of a high-strength special steel wire having a rhombic cross section, for example, a cold-worked 18-8 stainless steel wire in a cylindrical spring shape. It is made by winding it around.

  As shown in FIGS. 10 and 11, the coil insert 100 is screwed and fixed to a tap hole 102 formed in a workpiece (base material) 101 with an insertion tool. Thereafter, the bolt 103 or the like is screwed with the helical coil insert 100 as an internal thread. By using the helical coil insert 100 in this way, a high screw fastening force can be obtained, and the bolt 103 can be repeatedly inserted and removed.

  On the other hand, instead of the coil insert 100, a self-tapping insert, which is an insert nut having a self-tapping function, which does not need to be screwed into a pilot hole formed in a base material depending on applications, is used from the viewpoint of work efficiency. Widely used.

  An example of a commercially available self-tapping insert is shown in FIGS. 12 and 13.

  That is, the self-tapping insert 1 has a male screw 2 formed on the outer peripheral surface and a female screw 3 formed on the inner peripheral surface. The male screw 2 formed on the outer peripheral surface has a so-called tapered shape in which one tip portion, in this example, the right tip portion 4 is inclined toward the tip end side in the axial direction. The tip part 4 of the self-tapping insert 1 is made easy to fit into the pilot hole of the base material.

  Further, the front end portion 4 of the self-tapping insert 1 is formed with split grooves 7 and 8 having a predetermined width in the circumferential direction over a predetermined length in the axial direction from the front end. In this example, the split grooves 7 and 8 are formed to face each other in the diameter direction, and form the cutting edge portion A of the self-tapping insert 1.

  As shown in FIG. 14, such a self-tapping insert 1 forms a pilot hole 104 in a base material 101 and does not perform tapping (FIG. 14A). In the prepared hole 104 formed in the base material 101, the front end portion of the self-tapping insert 1 is disposed on the prepared hole 104 with the split grooves 7 and 8 of the self-tapping insert 1 facing downward (FIG. 14B). )). Next, the tool 105 is attached to the self-tapping insert 1. That is, the screw part 106 of the tool 105 is screwed onto the inner peripheral side female screw part of the self-tapping insert 1 and attached, and the tool 105 is rotated. Accordingly, the self-tapping insert 1 is also rotated, and the self-tapping insert 1 is attached to the prepared hole 104 by self-tapping the prepared hole 104 (FIGS. 14C and 14D). Thereafter, the tool 105 is reversed, and the threaded portion 106 of the tool 105 is removed from the self-tapping insert 1 (FIG. 14E).

Japanese Patent No. 4018844

  In the above-described conventional self-tapping insert, the cutting edge portion formed by the split groove is preferably as long as possible in the axial direction in order to improve the biting into the base material pilot hole and improve workability. Accordingly, in some cases, the length of the self-tapping insert may be more than half of the length.

  However, when the cutting blade portion is lengthened, there is a problem that the mechanical strength of this portion is lowered and the self-tapping insert itself is weakened.

  Therefore, as shown in FIG. 15, instead of the split grooves 7 and 8 formed in the self-tapping insert 1, a circular recess 9 is formed on the outer peripheral surface.

  In such a configuration, the cutting blade portion A is too small and the working efficiency is poor. Furthermore, although the chip produced by the self-tap is accumulated in the recess, it cannot be used for a self-tapping insert in which the amount of the chip is increased.

  In the self-tapping insert 1 shown in FIG. 15, there is a configuration in which a through hole is used instead of the recess 9.

  Therefore, an object of the present invention is to make it possible to take a large cutting edge portion and to remove and remove the chips generated by the self-tap very smoothly downward, which can significantly improve the working efficiency. It is to provide a tapping insert.

  Another object of the present invention is to provide a self-tapping insert that can be stably set in a prepared hole of a workpiece (base material) and can improve workability.

The above objective is accomplished by a self-tapping insert according to the present invention. In summary, the present invention provides a self-tapping insert in which a male screw is formed on the outer peripheral surface, a female screw is formed on the inner peripheral surface, and one tip portion is tapered toward the tip end side in the axial direction.
Located on the tip side, a plurality of cutting blade forming recesses are provided evenly in the outer circumferential direction,
The cutting edge forming recess passes through a position (a) at a predetermined distance (N1) in the axial direction from the end surface of the tapered tip portion, and has an angle α1 toward the end surface of the tapered tip portion with respect to the axis. A self-tapping insert characterized in that it has a cutting surface that is located in a vertical plane that forms a cutting surface that is cut from the outer peripheral surface toward the inner peripheral surface, and that forms a cutting blade portion that performs a tap function. is there.

  According to an embodiment of the present invention, the angle α1 is 15 ° to 30 °.

  According to another embodiment of the present invention, the bottom portion of the cutting blade portion-forming recess extends in the circumferential direction from the cutting surface, the male screw outer peripheral surface and the tip end surface from the bottom end edge of the cutting surface. It is a curved or flat inclined surface leading to the top.

  According to another embodiment of the present invention, there is provided a second cutting edge forming recess that is connected to the cutting edge forming recess and formed in a circumferential direction opposite to the cutting surface.

  According to another embodiment of the present invention, the cylindrical guide portion is provided at a predetermined distance (N4) in the axial direction from the end face of the tapered tip portion.

  According to another embodiment of the present invention, the outer peripheral portion of the guide portion is included inside the inclination angle β of the tapered tip portion.

  According to the present invention, the cutting edge portion can be made large without reducing the strength of the self-tapping insert. In addition, the chips generated by the self-tap can be removed very smoothly by being guided by a cutting blade portion forming recess formed so as to be connected to the cutting blade portion. Therefore, work efficiency can be remarkably improved. Further, by providing the guide portion at the tip end portion of the tapered shape, it can be stably set in the prepared hole of the workpiece (base material), and the workability can be further improved.

It is a perspective view which shows one Example of the self-tapping insert which concerns on this invention. It is a front view which shows one Example of the self-tapping insert which concerns on this invention. FIG. 3 is a right side view of the self-tapping insert of FIG. 2. It is sectional drawing of the self-tapping insert of FIG. It is a front view which shows the other Example of the self-tapping insert which concerns on this invention. FIG. 6 is a right side view of the self-tapping insert of FIG. 5. It is a front view which shows the other Example of the self-tapping insert which concerns on this invention. It is sectional drawing of the self-tapping insert of FIG. It is a figure explaining the mounting | wearing aspect at the time of setting the self-tapping insert of FIG. 7 in the prepared hole of a workpiece. It is a figure explaining the usage method of a helical coil insert. It is a figure explaining the state with which the helical coil insert was mounted | worn with the workpiece. It is a perspective view of the conventional split groove type self-tapping insert. It is a fragmentary sectional view of the self-tapping insert of FIG. It is a figure explaining the mounting method with respect to the workpiece of a self-tapping insert. It is a perspective view of the other type of conventional self-tapping insert.

  Hereinafter, the self-tapping insert according to the present invention will be described in more detail with reference to the drawings.

Example 1
1 to 4 show an embodiment of a self-tapping insert 1 according to the present invention.

  According to this embodiment, the self-tapping insert 1 has a male screw 2 formed on the outer peripheral surface and a female screw 3 formed on the inner peripheral surface, as in the conventional case. The male screw 2 formed on the outer peripheral surface has a so-called tapered shape (tapered shape) in which one distal end portion, in this example, the right distal end region 4 is inclined toward the distal end side in the axis O1-O2 direction. As described above with reference to FIG. 14, the tip portion 4 of the self-tapping insert 1 is easily fitted into the pilot hole 104 of the base material 101 at the start of processing.

  In this embodiment, the self-tapping insert 1 has a male screw 2 of M6 (pitch 1.5 mm), a female screw 3 of M1.0, an outer diameter D1 of 10 mm, an inner diameter D2 of 5 mm, and a total length L1 of 7 in FIG. Two types, 5 mm and 11.5 mm, were produced. The elongated tip 4 has a distance L2 from the end face 5 of 4 mm and a taper angle β of 8 °. It should be understood that the self-tapping insert 1 of the present invention is not limited to the above dimensions and shapes.

  According to the present embodiment, the front end portion 4 of the self-tapping insert 1 is replaced with the conventional dividing grooves 7 and 8 (see FIG. 12) which are formed opposite to each other in the diameter direction and have a predetermined width in the circumferential direction. Then, the cutting blade portion forming recess 10 is formed. In the present embodiment, the cutting blade portion forming recesses 10 are provided on the outer peripheral surface of the tip portion at a plurality of locations equally in the outer peripheral direction, in this embodiment, three locations. However, it is not limited to this, it may be two places, and in some cases, it may be four places or more. Each of the cutting blade portion forming recesses 10 is usually the same shape and size.

  Next, the cutting edge portion forming recess 10 is a predetermined distance (N1) along the axis O1-O2 from the front end surface 5 of the self-tapping insert 1 to the opposite end portion in the front view shown in FIG. A cutting plane A perpendicular to the axis O1-O2 at an angle α1 from the position a located in the direction of the front end face 5 is provided. The cutting surface A constitutes a cutting blade portion having a mountain shape between the position a and the outer peripheral surface position b1 on the end surface 5 of the distal end portion of the cutting surface A, that is, the outer end edge ab1 is continuous. .

  That is, the cutting surface A of the cutting blade portion forming recess 10 is a position on the outer peripheral surface where the male screw 2 is formed, and is a predetermined distance (N1) from the end surface 5 of the tapered tip portion 4 in the direction of the axis O1-O2. ) Is positioned in a vertical plane (ZZ plane) that forms an angle α1 toward the end face 5 of the tapered tip 4 with respect to the axis O1-O2 and passes from the outer circumference to the inner circumference. A vertical cut surface cut in the direction. The cut surface A forms a cutting blade portion that performs a tap function.

  The distance N1 along the axis O1-O2 from the end surface 5 to the position a is appropriately selected according to the total length L1 of the self-tapping insert 1, but is usually about 1/2 (1 / 2L) of the total length L1, or The number of threads of the male screw is about 2-6. However, if necessary, as indicated by a two-dot chain line in FIG. 2, N1 = L1 and the cutting edge forming recess 10 may be formed over the entire length L1 of the self-tapping insert 1. In this embodiment, it is set to 1/2 of the total length L1. Moreover, it is preferable that angle (alpha) 1 is larger than 0 degree and smaller than 45 degrees from the point of the performance of a cutting blade part. More preferably, it is formed at any angle in the range of 15 ° to 30 °. In this example, α1 = 15 °, and good results were obtained. However, the self-tapping insert 1 of the present invention is not limited to the above dimensional shape.

  The cutting depth N2 from the end edge b1 to the bottom position b2 (see FIG. 3) at the distal end portion 5 of the cutting surface A is set to a size that does not reach the valley portion of the female screw 3 formed on the inner peripheral portion. Therefore, according to the present embodiment, although the cutting edge forming recess 10 is formed, the split groove is not formed in the circumferential direction as in the prior art, and the strength of the self-tapping insert 1 is increased. There is no decline.

  Usually, the cutting depth N2 of the cut surface A at the end face 5 is about 1 to 1.5 mm. However, it is not limited to this value. In this embodiment, the thickness is 1.3 mm.

  The bottom B extending in the circumferential direction from the cutting surface A of the cutting edge forming recess 10 is at an edge a-b2, an edge b2-c, an edge cd, and an edge d-a. The bottom B to be formed is a curved surface. The curved surface B is formed by cutting the base material cut by the cutting blade portion A toward the tip 5 of the self-tapping insert 1 and further outward from the tip (for example, the lower portion in the pilot hole). The function to guide to the removal. That is, the chips of the base material cut by the cutting blade portion A rotate while being pushed by the cutting blade portion (vertical cutting surface) A by the rotation of the self-tapping insert 1, and the tip 5 of the self-tapping insert 1. Is dropped to the outside (for example, the lower part in the pilot hole) and removed.

  Therefore, as shown in FIG. 3, in this embodiment, the tip edge b2-c from the bottom position b2 of the cutting surface A at the tip position of the self-tapping insert 1 to the circumferential position c is a curve with a radius R. It is said. Usually, the radius R is larger than the outer diameter of the self-tapping insert 1. However, it is not limited to this. Further, the position c is set to an angle α2 from the horizontal axis HH passing through the position a and the axis center O of the self-tapping insert 1 in FIG. Usually, the angle α2 is 30 ° or more and 90 ° or less, and 45 ° in this embodiment. Further, the cutting depth N3 from the outer peripheral surface of the male screw at the position c can be set as appropriate. However, in order to efficiently discharge chips, it is preferable that N3 ≦ N2.

  As described above, the edge of the cutting edge forming recess 10 on the side opposite to the tip edge b2-c is the edge a-d that is in contact with the male thread outer periphery of the self-tapping insert. Therefore, as described above, in this embodiment, the bottom B of the curved surface is formed by the bottom edge a-b2, the tip edge b2-c, the end edge cd, and the edge d-a. Is formed.

  That is, in this embodiment, the bottom B of the cutting edge forming recess 10 extending in the circumferential direction with respect to the cutting surface A is from the bottom edge a-b2 of the cutting surface A to the male screw outer peripheral surface a. -D and a curved inclined surface that reaches the end edge b2-c at the end face 5 of the front end.

  According to the present embodiment, adjacent to the cutting edge forming recess 10, that is, connected to the edge cd of the cutting edge forming recess 10, and further from the outer periphery of the male screw of the self-tapping insert 1. A second cutting edge forming recess 20 cut away toward the inside is formed. The second cutting blade portion forming recess 20 is generated in the cutting blade portion A, and the cutting powder guided to the cutting blade portion forming recess 10 is transferred from the cutting blade portion forming recess 10 to the self-tapping insert 1. It functions to guide and remove more efficiently outward (for example, the lower part in the pilot hole) through the tip 5 of the first.

  In the present embodiment, the circumferential edge position e that forms the second cutting edge forming recess 20 and the front edge c− to the position c of the cutting edge forming recess 10 at the front edge position of the self-tapping insert 1. e is a straight line. However, the present invention is not limited to this, and can be a curved line.

  According to the self-tapping insert 1 of the present embodiment having the above-described configuration, the cutting blade portion A can be made large without reducing the strength of the self-tapping insert 1. Further, the chips generated by the self-tap can be removed very smoothly by being guided by the cutting blade portion forming recesses 10 and 20 formed to be connected to the cutting blade portion A. Therefore, work efficiency can be remarkably improved.

Example 2
5 and 6 show another embodiment of the self-tapping insert 1 of the present invention.

  In this example, the entire configuration of the self-tapping insert 1 is the same as that of the example 1. In this example, the same size as that of the example 1 was produced. However, the first embodiment differs from the first embodiment in the shape of the cutting edge portion forming recess 10 as described below.

  Accordingly, the entire configuration of the self-tapping insert 1 and parts having the same function are denoted by the same reference numerals, and the description thereof is omitted here.

  Also in the present embodiment, as in the first embodiment, the cutting blade portion forming recesses 10 are equally provided on the outer peripheral surface of the tip portion, but the present invention is not limited to this and may be two locations. In some cases, there may be four or more. Each of the cutting blade portion forming recesses 10 is usually the same shape and size.

  Next, the cutting edge portion forming recess 10 is perpendicular to the axial direction from the position a located at a predetermined distance (N1) from the tip of the self-tapping insert 1 at an angle α1 in the front view shown in FIG. It has a cutting surface A. The cutting surface A is formed between the position a and the outer peripheral surface position b1 at the tip of the cutting surface A, that is, the cutting surface A having a mountain shape in which the outer peripheral edge ab1 is continuous. Such a configuration is the same as that of the first embodiment.

  The distance N1 along the axis O1-O2 from the end surface 5 to the position a is appropriately selected according to the total length L1 of the self-tapping insert 1, but is usually about 1/2 (1 / 2L) of the total length L1, or The number of threads of the male screw is about 2-6. As described in the first embodiment, N1 = L1 may be set as necessary, and the cutting edge forming recess 10 may be formed over the entire length of the self-tapping insert 1. In this example, like the example 1, it was set to 1/2 of the total length L1. Moreover, it is preferable that angle (alpha) 1 is larger than 0 degree and smaller than 45 degrees from the point of the performance of a cutting blade part. More preferably, it is the range of 15 degrees-30 degrees. In this example, α1 = 15 °, and good results were obtained. However, the self-tapping insert 1 of the present invention is not limited to the above dimensional shape.

  The cutting depth N2 from the edge b1 to the bottom position b2 at the tip 5 of the cut surface A is set to a size that does not reach the valley of the female screw 3 formed on the inner periphery. Therefore, also in the present embodiment, the cutting edge forming recess 10 is formed, but unlike the conventional case, no split groove is formed in the circumferential direction, and the strength of the self-tapping insert 1 is reduced. Never do.

  As shown in FIGS. 2 and 3, the bottom B of the cutting edge portion forming recess 10 is positioned in the circumferential direction c from the bottom position b2 of the cutting surface A at the tip position 5 of the self-tapping insert 1 in the first embodiment. The leading edge portion b2-c up to this point is a curve having a radius R, but in this embodiment, it is a straight line (see FIG. 6). Further, the position c is an angle α2 from the horizontal axis HH passing through the position a and the self-tapping insert shaft center O in FIG. 6, and the normal angle α2 is 10 ° to 45 °, and in this embodiment, The angle was 20 °.

  On the other hand, the edge part of the cutting blade part forming recess 10 opposite to the tip edge part b2-c is an edge part a-d that is in contact with the male thread outer peripheral part of the self-tapping insert. The edge a-d extends at an angle α3 with respect to the cutting edge end edge ab1 that forms the cutting edge A that is the cutting surface A. The angle α is normally 60 to 120 °, but in this embodiment, it is 90 °. However, it is not limited to this.

  Therefore, in the present embodiment, the bottom portion having a planar shape at the cutting edge bottom edge a-b2, the tip edge b2-c, the end edge cf, the outer peripheral edge df, and the edge da. B is formed.

  That is, in this embodiment, the bottom B of the cutting edge forming recess 10 extending in a direction substantially perpendicular to the cutting surface A in the circumferential direction is from the bottom edge ab2 of the cutting surface A. It is a flat inclined surface formed by the male screw outer peripheral surfaces ad, df, fc, and the tip end surface b2-c.

  As in the case of the first embodiment, the flat portion B is formed by cutting the base material cut by the cutting blade portion A outward from the tip 5 of the self-tapping insert 1 (for example, the lower portion in the pilot hole). The function to guide to the removal. That is, the chips of the base material cut by the cutting blade portion A rotate while being pushed by the cutting blade portion (vertical cutting surface) A by the rotation of the self-tapping insert 1, and the tip 5 of the self-tapping insert 1. To the outside (for example, the lower part in the pilot hole) and removed.

  According to the present embodiment, adjacent to the cutting blade portion forming recess 10, that is, connected to the edge portion cf of the cutting blade portion forming recess 10, and further, the external thread outer peripheral portion 2 of the self-tapping insert 1. A second cutting edge forming recess 20 is formed which is cut away further inward. The second cutting blade portion forming recess 20 is generated in the cutting blade portion A, and the cutting powder guided to the cutting blade portion forming recess 10 is transferred from the cutting blade portion forming recess 10 to the self-tapping insert 1. It functions to guide and remove from the tip 5 outward (for example, the lower part in the pilot hole) more efficiently.

  In the present embodiment, the circumferential edge position e that forms the second cutting edge forming recess 20 and the front edge c− to the position c of the cutting edge forming recess 10 at the front edge position of the self-tapping insert 1. e is a straight line.

  Further, the position e is an angle α4 from the horizontal axis HH passing through the position a and the self-tapping insert shaft center O in FIG. 6, and the normal angle α4 is 45 ° or more and 90 ° or less. The angle was 70 °.

  Also in the self-tapping insert 1 of the present embodiment, the cutting edge portion A can be made large without reducing the strength of the self-tapping insert 1 as in the first embodiment. Further, the chips generated by the self-tapping can be removed very smoothly by being guided by the cutting blade portion forming recesses 10 and 20 formed so as to be connected to the cutting blade portion A. Therefore, work efficiency can be remarkably improved.

Example 3
7 and 8 show another embodiment of the self-tapping insert 1 of the present invention.

  In this example, the entire configuration of the self-tapping insert 1 is the same as that of Example 1, and the same thing as Example 1 was also produced in this example. However, it differs from Example 1 in the shape of the front-end | tip part 4 made into the taper (taper) shape of the external thread 2 formed in an outer peripheral surface so that it may demonstrate below.

  That is, according to the present embodiment, the cylindrical guide portion 6 is formed from the end surface 5 of the tapered tip portion 4 over the predetermined distance (N4) in the axis O1-O2 direction. For example, the guide portion 6 can be manufactured by using the self-tapping insert 1 of the first embodiment and cutting the male screw portion into a cylindrical shape by post-processing the tip portion 4.

  As shown in FIG. 9, the cylindrical guide portion 6 has a shape that fits into the pilot hole 104 of the base material (workpiece) 101. Therefore, according to the present embodiment, the self-tapping insert 1 has a tapered shape at the tip portion 4 of the self-tapping insert 1, and the guide portion 6 is further provided on the end face side of the tip portion 4. The center axis of the lower hole 104 is easily aligned and can be fitted straight, and can be stably set by the lower hole 104 of the base material 101 during processing, thereby improving workability.

  In the present embodiment, the length N4 of the guide portion 6 is not limited, but is about one pitch of the male screw 2. Further, the dimension of the outer peripheral portion of the guide portion 6, that is, the outer diameter D <b> 3 is slightly smaller than the inner diameter D <b> 0 of the lower hole 104 so that the outer diameter D <b> 3 can be smoothly fitted into the lower hole 104. For example, the diameter is usually D0−D3 = 0.1 to 0.2 mm. Moreover, the outer peripheral part (outer diameter D3) of the guide part 6 is made into the dimension included inside taper angle (beta) of the front-end | tip part 4 made into a taper shape.

  Naturally, the guide portion 6 described in the present embodiment can also be applied to the self-tapping insert 1 described in the second embodiment.

DESCRIPTION OF SYMBOLS 1 Self-tapping insert 2 Male thread outer peripheral surface 3 Female screw inner peripheral surface 4 Elongated shape front-end | tip part 5 Elongated front-end | tip part end surface 6 Guide part 10 Cutting blade part formation recess 20 2nd cutting blade part formation recess A Cutting edge part formation recess Cutting surface (cutting edge)
B Cutting edge forming recess bottom

Claims (6)

In a self-tapping insert in which a male screw is formed on the outer peripheral surface, a female screw is formed on the inner peripheral surface, and one tip is tapered to the tip in the axial direction.
Located on the tip side, a plurality of cutting blade forming recesses are provided evenly in the outer circumferential direction,
The cutting edge forming recess passes through a position (a) at a predetermined distance (N1) in the axial direction from the end surface of the tapered tip portion, and has an angle α1 toward the end surface of the tapered tip portion with respect to the axis. A self-tapping insert having a cutting surface that is located in a vertical plane that forms a cutting surface that is cut from the outer peripheral surface toward the inner peripheral surface, and that has a tapping function.   2. The self-tapping insert according to claim 1, wherein the angle [alpha] 1 is 15 [deg.] To 30 [deg.].   The bottom of the cutting blade forming recess extending in the circumferential direction from the cutting surface is a curved or flat slope extending from the bottom edge of the cutting surface to the outer peripheral surface of the male screw and the end surface of the tip. The self-tapping insert according to claim 1 or 2, wherein the self-tapping insert is a surface.   The second cutting blade portion forming recess formed in the circumferential direction opposite to the cutting surface is connected to the cutting blade portion forming recess. Self tapping insert.   The self-tapping insert according to any one of claims 1 to 4, further comprising a cylindrical guide portion at a predetermined distance (N4) in an axial direction from an end face of the tapered tip portion.   6. The self-tapping insert according to claim 5, wherein an outer peripheral portion of the guide portion is included inside an inclination angle β of the tapered tip portion.

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