JP2005007513A - Deep hole cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connecting structure of a connecting part of a deep hole cutting tool, for easily and properly connecting both connecting end parts, when connecting a drill head to a shank. <P>SOLUTION: This connecting structure of the connecting part in the deep hole cutting tool, forms cross-sectional V-shaped chip discharge grooves 4 and 5 on the shank 3 and the drill head 2, by detachably connecting the drill head 2 to a tip part of the shank 3. A small diameter shaft part 10 and a large diameter shaft part 11 are continuously arranged in one of both the connecting end parts. A small diameter hole part 14 and a large diameter hole part 15 fitted to the small diameter shaft part 10 and the large diameter shaft part 11 by a socket and spigot joint, are continuously arranged in the other connecting end part fitted around one connecting end part. A key 17 is interposed between the small diameter shaft part 10 and the small diameter hole part 14. The axial directional relative movement is checked by a side lock screw 20 pressed to an outer peripheral surface of one connecting end part, by being screwed in the radial direction in the other connecting end part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a deep hole cutting tool such as a drill or a reamer applied to a gun drill system.
[0002]
[Prior art]
As a deep hole drilling system, a gun drill system, a BTA system, an ejector system, and the like are known, but a gun drill system with a simple configuration is widely used for drilling a relatively small diameter deep hole. This gun drill system has a hollow cylindrical shape, and a gun drill in which a drill head having a chip discharge groove formed on the outer peripheral surface is attached to the tip of a shank formed with a chip discharge groove having a substantially V-shaped cross section along the longitudinal direction on the outer peripheral surface. When drilling deep holes, high-pressure coolant is discharged from the tip of the drill head through the supply passage inside the drill, and chips generated in the cutting hole of the workpiece are discharged to the outside together with the coolant from the chip discharge groove. Therefore, there is an advantage that chips can be discharged relatively easily by taking a large space for the chip discharge grooves even with a small diameter.
[0003]
An example of such a gun drill is shown in FIG. 6 filed earlier by the present applicant (see Patent Document 1). This gun drill 31 is formed by connecting a drill head 32 to the tip of a long shank 33. The shank 33 and the drill head 32 have a substantially V-shaped cross section along the longitudinal direction on the outer peripheral surface thereof. Grooves 34, 35a, and 35b are formed, the shank 33 is divided into a plurality (usually two), and the divided end portions of the divided shank portions 33a and 33b are detachably connected.
[0004]
The drill head 33 and the shank 32 are connected by screwing the male screw portion m at the base end portion of the drill head 32 into the female screw portion f at the distal end portion of the shank 33, and the divided shank portions 33a and 33b are divided. The ends are also connected by screwing a male screw portion m of the other divided end into a female screw portion f of one divided end portion. In FIG. 6, reference numeral 33o denotes a large-diameter driven shaft portion formed at the proximal end portion of the shank 33, which is held by a chuck or the like and receives a rotational driving force. Reference numeral 36 denotes a coolant supply passage formed over the entire inner length of the shank 33.
[0005]
[Patent Document 1]
Japanese Patent Application No. 2002-332124 (7th to 10th pages, FIGS. 1 to 4)
[0006]
[Problems to be solved by the invention]
As described above, in the conventional gun drill, the connecting structure between the drill head 32 and the shank 33 is a screw-type connecting structure including the female screw part f and the male screw part m. In many cases, the screw portions f and m that are the connecting portions are damaged, and when the drill head 2 is removed, the male and female screw portions f and m cannot be loosened. was there. The same applies to the connection structure between the divided shank portions 33a and 33b.
[0007]
In view of the above-described problems, the present invention provides a deep hole cutting tool that can easily and properly connect both connecting end portions when connecting the rear end portion of the drill head to the tip end portion of the shank. The purpose is to do. It is another object of the present invention to provide a deep hole cutting tool that can easily and properly connect the split ends of the shank together with the connection between the drill head and the shank.
[0008]
[Means for Solving the Problems]
In the invention according to claim 1, the drill head 2 is detachably connected to the tip of the shank 3, and the chip discharge groove 4 having a substantially V-shaped cross section along the longitudinal direction on the outer peripheral surface of the shank 3 and the drill head 2. In the deep hole cutting tool in which 5 is formed, the small diameter shaft portion 10 on the end portion side and the large diameter shaft portion 11 on the inner side thereof are coaxially formed on one of the connecting end portions connected to each other. A small-diameter hole portion 14 and a large-diameter hole that are continuously fitted and fitted into the small-diameter shaft portion 10 and the large-diameter shaft portion 11 in the axial direction on the other connection end portion that is externally fitted to the one connection end portion. The portion 15 is connected coaxially, and relative rotation of both connecting end portions is performed between the small diameter shaft portion 10 and the small diameter hole portion 14 or between the large diameter shaft portion 11 and the large diameter hole portion 15. A blocking key 17 is interposed, and the other connecting end is screwed in the radial direction so that the outer periphery of the one connecting end is Characterized in that it adapted to relative axial movement of the connecting end of both is prevented by the side locking screw 20 is pressed against the.
[0009]
In the invention according to claim 2, the drill head 2 is detachably connected to the tip of the shank 3, the shank 3 is divided into a plurality of parts, and the divided shanks 3a and 3b are detachably connected to each other. 3 and a deep hole cutting tool in which chip discharge grooves 4 and 5 having a substantially V-shaped cross section are formed along the longitudinal direction on the outer peripheral surface of the drill head 2, The small-diameter shaft portion 10 on the end side and the large-diameter shaft portion 11 on the inner side thereof are coaxially connected to each other, and the small-diameter portion is connected to the other connection end portion that is externally fitted to the one connection end portion. A small-diameter hole portion 14 and a large-diameter hole portion 15 that are fitted in the axial direction to the shaft portion 10 and the large-diameter shaft portion 11 are coaxially connected to each other, and between the small-diameter shaft portion 10 and the small-diameter hole portion 14. Alternatively, a key that prevents relative rotation of both connecting end portions between the large-diameter shaft portion 11 and the large-diameter hole portion 15. 7 and a side lock screw 20 that is screwed into the other connecting end portion in the radial direction and pressed against the outer peripheral surface of the one connecting end portion prevents the relative movement of both connecting end portions in the axial direction. It is characterized by being designed.
[0010]
According to a third aspect of the present invention, in the deep hole cutting tool according to the first or second aspect, the key 17 is provided so as to protrude from the inner peripheral surface of the small-diameter hole portion 14 of the other connecting end portion. The key groove 12 fitted in the direction is formed on the outer peripheral surface of the small-diameter shaft portion 10 of the one connecting end portion.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a preferred embodiment of a deep hole cutting tool according to the present invention will be specifically described with reference to the drawings. 1A is a front view of the drill head 2 in the gun drill 1 shown in FIG. 3, FIG. 1B is a side view of the drill head 2 viewed from the front end side, and FIG. 1C is a side view of the drill head 2 viewed from the rear end side. is there. FIG. 2 is a front view showing the tip side portion of the shank 3 of the gun drill 1, and FIG. 2B is a side view of the drill head 2 as seen from the tip side. FIG. 3 is a front view of the state in which the rear end portion of the drill head 2 is connected to the front end portion of the shank 3. 4A is a perspective view showing the tip side of the drill head 2 and the shank 3, and FIG. 4B is a perspective view of the rear end of the drill head 2 viewed from the side opposite to the chip discharge groove 4. FIG. . The shank 3 of the gun drill 1 is not divided into a plurality of pieces but is a single continuous unit.
[0012]
As shown in FIGS. 1 and 4, the drill head 2 includes a large-diameter head main body portion 2a and a rear end connecting shaft portion 2b (connecting end portion) extending coaxially from the rear end of the head main body portion 2a. Become. A chip discharge groove 4 having a substantially V-shaped cross section along the longitudinal direction is formed on the outer peripheral surfaces of the head main body 2a and the rear end connecting shaft 2b, and the head main body extends from the rear end of the rear end connecting shaft 2b. A coolant supply pipe 6 is integrally formed along the central axis O across the portion 2a.
[0013]
As can be seen from FIGS. 1A to 1C and FIGS. 4A and 4B, a carbide tip 8 and a guide pad 9 forming a cutting edge are formed on the tip side of the head body 2 a. It is fixed. The rear end connecting shaft portion 2b includes a small-diameter shaft portion 10 on the rear end portion side and a large-diameter shaft portion 11 provided on the inner side of the small-diameter shaft portion 10 so as to be coaxially connected. On the outer peripheral surface of the rear end connecting shaft portion 2b, a key groove 12 into which a key 17 on the shank 3 described later is fitted in the axial direction at a position opposite to the chip discharge groove 4 is provided at the rear of the small diameter shaft portion 10. It is formed over a length slightly shorter than the length of the small diameter shaft portion 10 from the end. Further, on the outer peripheral surface of the small-diameter shaft portion 10, there are provided, for example, two engaging recesses 23 that engage with a pointed portion of a side lock screw 20 described later. 1 and 3, reference numeral 24 denotes a coolant discharge port that communicates with the coolant supply pipe 6 of the drill head 2 and opens at the front end surface of the head body 2 a.
[0014]
FIGS. 2 and 4 (a) show only the tip side portion of the shank 3, but the base end portion of the shank 3 is held by a chuck or the like as in the conventional gun drill 31 shown in FIG. A large-diameter driven shaft portion for receiving a driving force is provided, and a chip discharge groove 5 having a substantially V-shaped cross section along the longitudinal direction is formed on the outer peripheral surface of the shank 3. A hollow portion 13 for inserting a coolant supply pipe is formed along the central axis O, and the coolant supply pipe 7 is inserted into the hollow portion 13 as indicated by an imaginary line in FIG. In this embodiment, the chip discharge groove 5 of the shank 3 and the chip discharge groove 4 of the drill head 2 are formed at an opening angle of 90 ° from the central axis O of each of the shank 3 and the drill head 2. The angle can be set to an appropriate opening angle in the range of about 90 ° to 130 °.
[0015]
Further, as shown in FIGS. 2A and 2B and FIG. 4A, the tip 3s (connecting end) of the shank 3 is connected to the rear end connecting shaft 2b (connecting shaft) of the drill head 2. The cylindrical portion (that is, the shank tip portion 3s) is formed on the outer diameter side small diameter hole portion 14 and the end portion side (outer side). The large-diameter hole portion 15 includes a small-diameter hole portion 14 and a large-diameter hole portion 15 that are fitted in the axial direction to the small-diameter shaft portion 10 and the large-diameter shaft portion 11 of the drill head rear end connecting shaft portion 2b. It has become.
[0016]
A key that is slidably fitted only in the axial direction to the key groove 12 formed on the outer peripheral surface of the small-diameter shaft portion 10 of the drill head 2 on the inner peripheral surface of the small-diameter hole portion 14 of the shank tip 3 s. 17 protrudes. As shown in FIG. 2B, the key 17 is fitted into a key fitting recessed portion 16 provided on the inner peripheral surface of the small-diameter hole portion 14 and is required from the inner peripheral surface of the small-diameter hole portion 14. It protrudes in height and is fixed by screws 18 screwed from the inner surface side of the key 17 (see FIG. 4A).
[0017]
The shank tip portion 3s is provided with screw holes 19 that open from the outer peripheral surface of the tip portion 3s to the inner peripheral surface of the small diameter hole portion 14 at a plurality of circumferential positions, for example, two locations. A side lock screw 20 is screwed into the screw hole 19. The side lock screw 20 is screwed into the screw hole 19 of the shank tip 3 s and pressed against the outer peripheral surface of the small-diameter shaft portion 10 on the drill head 2 side, thereby causing relative movement in the axial direction between the drill head 2 and the shank 3. It is a deterrent. As shown in FIG. 1 (c) and FIG. 4 (a), on the outer peripheral surface of the small-diameter shaft portion 10 on the drill head 2 side, there is provided an engagement recess 23 that engages the tip of the side lock screw. .
[0018]
In order to connect the rear end connecting shaft portion 2b (connecting end portion) of the drill head 2 to the tip portion 3s (connecting end portion) of the shank 3 having the above-described configuration, as can be seen from FIG. The drill head 2 is coaxially arranged on the front end side, and the cylindrical front end portion 3s of the shank 3 is fitted on the rear end connecting shaft portion 2b of the drill head 2 (in other words, the rear end connection of the drill head 2 is connected). The shaft portion 2b is fitted into the cylindrical shank tip portion 3s), and the small diameter shaft portion 10 and the large diameter shaft portion 11 of the drill head rear end connecting shaft portion 2b are connected to the small diameter hole portion 14 and the large diameter hole of the shank tip portion 3s. An inlay fit is made in the axial direction to the portion 15, and the key 17 on the shank tip 3 s side is fitted in the key groove 12 on the drill head rear end connecting shaft 2 b side in the axial direction, and then on the shank tip 3 s side. The side lock screw 20 is screwed into the screw hole 19, and the It tightened strongly against the end the engagement recess 23 on the outer peripheral surface of the drill head 2 side small-diameter shaft portion 10.
[0019]
In this case, the small-diameter shaft portion 10 and the large-diameter shaft portion 11 of the drill head rear end connecting shaft portion 2b are inlay-fitted in the axial direction with the small-diameter hole portion 14 and the large-diameter hole portion 15 of the shank tip 3s. The drill head 2 and the shank 3 are joined concentrically. At this time, the boundary end surface 21 between the small-diameter shaft portion 10 and the large-diameter shaft portion 11 abuts on the boundary end surface 22 between the small-diameter hole portion 14 and the large-diameter hole portion 15. The axial relative movement between the head 2 and the shank 3 is restricted. Therefore, it is the side lock screw 20 that maintains the contact state between the boundary end faces 21 and 22. The screw 20 is screwed into the screw hole 19 of the shank tip 3 s and the small diameter shaft portion 10 on the side of the drill head 2. By pressing against the outer peripheral surface, the axial relative movement of the drill head 2 and the shank 3 is reliably prevented. Further, when the key 17 on the shank tip 3s side is fitted in the key groove 12 on the drill head side, relative rotation between the drill head 2 and the shank 3 is prevented.
[0020]
It should be noted that the key 17 and the key groove 12 that prevent relative rotation between the drill head 2 and the shank 3 are axially connected to each other at a position where the chip discharge groove 4 on the drill head 2 side and the chip discharge groove 5 on the shank 3 side coincide with each other. It is set so that it may fit.
[0021]
As described above, the drill head 2 is coaxially disposed on the front end side of the shank 3, the rear end connecting shaft portion 2b of the drill head 2 is fitted into the shank front end portion 3s, and the small diameter shaft on the drill head 2 side is arranged. The portion 10 and the large-diameter shaft portion 11 are fitted in the axial direction with the small-diameter hole portion 14 and the large-diameter hole portion 15 of the shank tip portion 3s, and the key 17 on the shank tip portion 3s side is inserted into the key groove on the drill head 2 side. After the shaft 12 is fitted in the axial direction, the side lock screw 20 is screwed into the screw hole 19 on the shank tip 3 s side and pressed against the outer peripheral surface of the small diameter shaft portion 10 on the drill head 2 side. The end connecting shaft portion 2b can be easily and easily connected to the shank tip portion 3s so that they can be properly connected, and when removing, the side lock screw 20 can be loosened and the drill head 2 can be pulled in the axial direction. The damaged connecting portion overtighten as threaded connection structure, is not such as to difficult to remove.
[0022]
Moreover, in the connection structure of this embodiment, since the key 17 is provided so as to protrude to the inner peripheral surface of the small diameter hole portion 14 of the shank tip 3 s, the key 17 is protruded to the inner peripheral surface of the large diameter hole portion 15. Compared with the case of providing, since the cylindrical portion is thicker on the small-diameter hole portion 14 side than the large-diameter hole portion 15 side, the key fitting recessed portion 16 for attaching the key 17 can be formed sufficiently deeply, A screw 18 for fixing the key 17 to the recess 16 for fitting can be screwed in sufficiently deeply and can be securely fixed firmly. Further, since the small-diameter shaft portion 10 is on the distal end side of the drill head rear end connecting shaft portion 2b, the processing of the key groove 12 is easier on the outer peripheral surface of the small-diameter shaft portion 10 than on the outer peripheral surface of the large-diameter shaft portion 11. Become.
[0023]
FIG. 5 shows a gun drill 25 in which the shank 3 is divided into a plurality of parts, for example, two parts, and the divided shank parts 3a and 3b are detachably connected to each other, and only the part of the shank 3 is shown. In this case, the distal end portion 26 (connection end portion) of the proximal end side divided shank portion 3a is the same as the structure of the distal end portion 3s of the shank 3 in the gun drill 1 of the previous embodiment shown in FIG. The rear end portion 27 (connection end portion) of the portion 3b is the same as the structure of the rear end connection shaft portion 2b of the drill head 2 shown in FIG. 1, and the rear end portion 27 of the front end side divided shank portion 3b has a small diameter. The shaft portion 10 and the large-diameter shaft portion 11 are coaxially connected to each other, and the distal end portion 26 of the proximal-end-side divided shank portion 3a is fitted with the small-diameter shaft portion 10 and the large-diameter shaft portion 11 in the axial direction. The small-diameter hole portion 14 and the large-diameter hole portion 15 to be joined are connected coaxially, and a key 17 is interposed between the small-diameter shaft portion 10 and the small-diameter hole portion 14 to prevent relative rotation of both. The end-side split shank 3b is screwed in the radial direction from the tip 26 of the end-side split shank 3a. Side lock screw 20 is pressed against the end 27 the outer peripheral surface is provided.
[0024]
The connection structure between the divided shank portions 3a and 3b of the gun drill 21 is the same as the connection structure between the rear end connection shaft portion 2b of the drill head 2 and the front end portion 3s of the shank 3 in the gun drill 1 of the previous embodiment. Therefore, detailed illustration of the connection structure and description of its operation are omitted. In this gun drill 21 as well, the coolant supply pipe 7 is inserted into the hollow portion 13 formed along the central axis of the divided shank portions 3a and 3b.
[0025]
In the embodiment described above, the coolant supply path (coolant supply pipe 7) of the shank 3 is provided at a position along the central axis of the shank 3. However, the connection structure of the present invention has the coolant supply path as described above. The present invention is not limited to the case where it is provided at the center position of the shank 3, but can also be applied to the case where it is provided at a position eccentric from the center axis of the shank as in the coolant supply path 36 shown in the conventional example of FIG.
[0026]
Moreover, in the above embodiment, the small-diameter shaft portion 10 and the large-diameter shaft portion 11 are provided in the rear end connecting shaft portion 2b of the drill head 2, and the shank tip portion 3s is hollowed so that the small-diameter hole portion 14 and the diameter are formed. Although the large hole portion 15 is formed, the rear end connecting shaft portion 2b of the drill head 2 is hollowed to form a small diameter hole portion 14 and a large diameter hole portion 15, and the small diameter shaft portion 10 and the diameter of the shank tip portion 3s are formed. The large shaft portion 11 may be provided. In the embodiment, the small-diameter shaft portion 10, the large-diameter shaft portion 11, the small-diameter hole portion 14, and the large-diameter hole portion 15 are formed straight, but may be formed in a tapered shape.
[0027]
【The invention's effect】
According to the deep hole cutting tool of the first aspect of the invention, instead of the conventional screw-type connection structure, the small diameter shaft portion and the large diameter shaft portion are coaxially connected to one of both connection ends, A small diameter hole portion and a large diameter hole portion that are axially fitted into the small diameter shaft portion and the large diameter shaft portion are coaxially connected to the other connection end portion that is externally fitted to one connection end portion. A key for preventing relative rotation between the small-diameter shaft portion and the small-diameter hole portion or between the large-diameter shaft portion and the large-diameter hole portion is interposed and screwed into the other connecting end portion. The side lock screw pressed against the outer peripheral surface of the connecting end of the two is prevented from relative movement in the axial direction, so one connecting end is fitted into the other connecting end in the axial direction, While fitting the small diameter shaft portion and large diameter shaft portion of the end portion in the axial direction to the small diameter hole portion and large diameter hole portion of the other connecting end portion, After fitting the key in the keyway in the axial direction, simply tightening the side lock screw makes it easy to connect both ends easily and easily, and loosens the side lock screw when releasing the connection. It is only necessary to pull the end portion in the axial direction, and it does not damage the connecting portion and make it difficult to remove it as in the conventional screw type connecting structure. Further, since the structure is very simple and the number of members is small, the manufacturing is easy and the cost can be reduced.
[0028]
The invention according to claim 2 relates to each connection structure when connecting the rear end portion of the drill head and the tip end portion of the shank and connecting the divided shank portions of the shanks divided into a plurality of portions. Similarly to the first aspect of the invention, one connecting end portion is fitted in the other connecting end portion in the axial direction, and the small diameter shaft portion and the large diameter shaft portion of the one connecting end portion are the diameters of the other connecting end portion. Fits the small hole part and large diameter hole part in the axial direction, and after fitting the key in the key groove in the axial direction, tightening the side lock screw makes it easy and easy to connect both ends. They can be connected, and can be easily and easily released simply by loosening the side lock screw and pulling the connecting end in the axial direction.
[0029]
According to the third aspect of the invention, since the key is provided so as to protrude from the inner peripheral surface of the small-diameter hole portion of the connecting end portion, when the key is provided so as to protrude from the inner peripheral surface of the large-diameter hole portion of the connecting end portion. In comparison, since the cylindrical portion is thicker on the small-diameter hole side than on the large-diameter hole side, the key fitting concave portion for attaching the key can be formed sufficiently deep, and the key is fixed to the fitting concave portion. Can be screwed in sufficiently and can be securely fixed. Further, since the small-diameter shaft portion is on the distal end side of the connecting end portion, the key groove is more easily processed on the small-diameter shaft outer peripheral surface than on the large-diameter shaft outer peripheral surface.
[Brief description of the drawings]
1A is a front view of a drill head in the gun drill shown in FIG. 3, FIG. 1B is a side view of the drill head viewed from the distal end side thereof, and FIG. 1C is a view of the drill head viewed from the proximal end side thereof; FIG.
FIG. 2A is a front view showing a front end portion of a shank of the gun drill, and FIG. 2B is a side view of the drill head as viewed from the front end side.
FIG. 3 is a front view of a gun drill in a state in which a rear end portion of a drill head is connected to a front end portion of a shank.
4A is a perspective view of a state in which the drill head is cut off from the tip end portion of the shank, and FIG. 4B is a perspective view of the rear end portion of the drill head as viewed from the side opposite to the chip discharge groove.
5A and 5B show an embodiment of a gun drill in which a shank is divided into a plurality of parts, wherein FIG. 5A is a front view of the shank, and FIG. 5B is a cross-sectional view taken along line YY of FIG.
6A is a front view showing a conventional gun drill, and FIG. 6B is a sectional view taken along line XX of FIG.
[Explanation of symbols]
1,25 Gun drill (deep hole cutting tool)
2 Drill head 3 Shank 3a Divided shank part 4, 5 Chip discharge groove 10 Small diameter shaft part 11 Large diameter shaft part 12 Key groove 14 Small diameter hole part 15 Large diameter hole part 17 Key 20 Side lock screw

Claims (3)

In a deep hole cutting tool in which a drill head is detachably connected to the tip of the shank, and a chip discharge groove having a substantially V-shaped cross section is formed along the longitudinal direction on the outer peripheral surface of the shank and the drill head. One end of each of the connecting ends has a small-diameter shaft portion on the end portion side and a large-diameter shaft portion on the inner side thereof coaxially connected to each other, and the other end that is externally fitted to the one connecting end portion. A small-diameter hole portion and a large-diameter hole portion that are axially fitted into the small-diameter shaft portion and the large-diameter shaft portion are coaxially connected to the connecting end portion, and the small-diameter shaft portion and the small-diameter hole portion are coaxially connected. Or a key that prevents relative rotation of both connecting end portions between the large-diameter shaft portion and the large-diameter hole portion, and is screwed into the other connecting end portion in the radial direction to The side lock screw pressed against the outer peripheral surface of the connecting end of the joint prevents the relative movement of both connecting ends in the axial direction. Deep hole cutting tool has become so that. A drill head is detachably connected to the tip of the shank, and the shank is divided into a plurality of parts, and the divided shank parts are detachably connected to each other. In a deep hole cutting tool in which a V-shaped chip discharge groove is formed, one of the connecting end portions connected to each other includes a small shaft portion on the end portion side and a large shaft portion on the inner side thereof. Are connected in a coaxial manner, and the other connecting end that is externally fitted to the one connecting end has a small diameter hole portion and a diameter that are axially fitted into the small diameter shaft portion and the large diameter shaft portion. A key that is coaxially connected to the large hole portion and prevents relative rotation of both connecting end portions between the small diameter shaft portion and the small diameter hole portion or between the large diameter shaft portion and the large diameter hole portion. And is screwed in the radial direction to the other connecting end portion to the outer peripheral surface of the one connecting end portion. Deep hole cutting tool adapted to relative axial movement of the connecting end of both is prevented by attach is the side locking screw. The key is provided so as to protrude from the inner peripheral surface of the small-diameter hole portion of the other connecting end portion, and the key groove into which the key is fitted in the axial direction is formed on the outer peripheral surface of the small-diameter shaft portion of the one connecting end portion. The deep hole cutting tool of Claim 1 or 2 currently formed.

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