TURNING TOOL

Abstract

A turning tool for metal cutting includes a tool body with an insert seat, a clamping member and a clamping pin. The clamping pin connects the tool body and the clamping member to clamp a cutting insert in the insert seat. A shaft of the clamping pin is axially movably received in the tool body bore and moveable to a first axial position. The clamping pin, in the first axial position, engages the clamping member and forces the clamping member towards a tool body top surface, to clamp the cutting insert in the seat. In the first axial position, a first coolant fluid outlet opening in the head is located above a top surface of the clamping member. A locking mechanism, in the first axial position, releasably locks the shaft in the bore preventing axial sliding toward the tool body top surface.

Claims

1. A turning tool for metal cutting comprising: a tool body having a tool body top surface, and arranged at a front end of the tool body top surface, an insert seat arranged for receiving a cutting insert, and a tool body bore that is spaced apart from the insert seat and extends downward from an opening in the tool body top surface; a clamping member arranged at the tool body top surface, the clamping member including a base body having a base body top surface, and a base body bottom surface facing the tool body top surface, a clamping member through hole extending from an opening in the base body top surface to an opening in the base body bottom surface, the clamping member through hole being aligned with the tool body bore, and a clamping arm protruding from the base body and at least a portion of the clamping arm extending over the insert seat; a clamping pin connecting the tool body and the clamping member, the clamping pin including a longitudinal shaft that has a longitudinal axis and that extends through the clamping member through hole and into the tool body bore, wherein the shaft is axially movably received in the tool body bore and operable to move to a first axial position, a head at an upper end of the shaft, and a coolant fluid channel having a first outlet opening in the head, wherein the clamping pin is configured to, in the first axial position, engage the base body and force the base body, together with the protruding clamping arm, toward the tool body top surface, whereby, when a cutting insert is received in the insert seat, the cutting insert is clamped in the insert seat, wherein in the first axial position, the first outlet opening in the head is located above the base body top surface, the shaft is axially movably received in the tool body bore by being axially slidable; and a locking mechanism configured to, in the first axial position, releasably lock the shaft in the tool body bore against at least axial sliding toward the tool body top surface.

2. The turning tool for metal cutting according to claim 1, wherein the locking mechanism is configured to, in the first axial position, releasably lock the shaft in the tool body bore against relative rotation by positive locking.

3. The turning tool for metal cutting according to claim 1, wherein the tool body includes a first tool body side surface extending downward from the tool body top surface at one side thereof, and wherein the locking mechanism includes a tool body side hole having a first portion connecting the first tool body side surface with the tool body bore, an abutment surface at the shaft, and an actuation bar movably mounted in the first portion of the tool body side hole and relative to the shaft, the actuation bar including, at an inner portion, an engagement section having an engagement surface for interacting with the abutment surface, and wherein the actuation bar is operable, when the shaft is in the first axial position, to move to a locking position, in which the engagement surface presses against the abutment surface to lock the clamping pin in the first axial position.

4. The turning tool for metal cutting according to claim 3, wherein the locking mechanism includes a shaft recess, which, from a shaft entrance opening, extends transverse to the longitudinal axis of the shaft, wherein, in the first axial position, the shaft entrance opening faces the first portion of the tool body side hole, and wherein the abutment surface is an upward facing surface in the recess, and wherein, when the actuation bar is in the locking position, the engagement section is located in the shaft recess.

5. The turning tool for metal cutting according to claim 4, wherein the abutment surface is an upward facing wedge surface that tapers toward the shaft entrance opening, the engagement surface having a downward facing wedge surface that tapers inward, and wherein, when the actuation bar is operated to move to the locking position, the engagement section moves inward in the shaft recess, whereby the engagement surface slides and presses against the abutment surface to force the shaft into the first axial position.

6. The turning tool for metal cutting according to claim 5, wherein, as seen in a cross section including the longitudinal axis of the shaft and a central longitudinal axis of the first portion of tool body side hole, the abutment surface and the engagement surface form an angle with the central longitudinal axis of the first portion of tool body side hole, the angle being at least 3° and at most 45°.

7. The turning tool for metal cutting according to claim 6, wherein the shaft recess is a through hole with a central longitudinal axis, which intersects the central longitudinal axis of the first portion of the tool body side hole at the angle.

8. The turning tool for metal cutting according to claim 5, wherein the engagement surface includes a surface that is shaped as a truncated cone, wherein the actuation bar includes a male thread in engagement with a female thread in the first portion of the tool body side hole, and wherein, when the actuation bar is operated to move to the locking position, the actuation bar is screwed inward.

9. The turning tool for metal cutting according to claim 7, wherein the tool body bore includes a coolant fluid inlet opening, wherein, when the shaft is in the first axial position, the coolant fluid inlet opening is located below a lower end of the shaft, the coolant fluid channel of the clamping pin being an internal channel having a coolant fluid inlet opening located in a downward facing surface in the shaft recess in form of the through hole, and wherein the shaft, between the lower end and a shaft exit opening of the through hole, has an outer surface portion which is located at a distance to the longitudinal axis that is smaller than the radius of the tool body bore to allow coolant fluid to pass by the shaft in the tool body bore from the inlet opening of tool body bore to the inlet opening of the internal channel of the clamping pin.

10. The turning tool for metal cutting according to claim 1, wherein the head has longitudinally extending front side surface, wherein the first outlet opening is located in the front side surface, wherein the coolant fluid channel includes a first internal exit channel, the first internal exit channel having a central longitudinal axis and extending from an inner position in the head to the first outlet opening, and wherein the central longitudinal axis of the first exit channel and the longitudinal axis of the shaft form a sharp angle having a value of 45° or more.

11. The turning tool for metal cutting according to claim 10, wherein an extension of the central longitudinal axis of the first exit channel intersects a point where, when a cutting insert is clamped in the insert seat, an active cutting edge of the cutting insert is located.

12. The turning tool for metal cutting according to claim 3, wherein the tool body includes a second tool body side surface, which extends downward from the tool body top surface on an opposite side of the first tool body side surface, wherein the tool body side hole includes a second portion connecting the second tool body side surface with the tool body bore, the shaft being axially slidable in the tool body bore in two angular positions spaced apart by 180° so that, in the first axial position, the shaft entrance opening selectively faces either the first portion of the tool body side hole, or the second portion of the tool body side hole, the coolant fluid channel a second outlet opening in the head, which second outlet opening is angularly spaced apart from the first outlet opening by 180°, and wherein the actuation bar selectively either is movably mounted in the first portion or in the second portion of the tool body side hole, and in both locations operable to, when the shaft is in the first axial position with a matching angular position, to move to the locking position.

13. The turning tool for metal cutting according to claim 1, wherein the clamping member is a separable component.

14. The turning tool for metal cutting according to claim 1, wherein the clamping member is biased away from the tool body top surface.

15. The turning tool for metal cutting according to claim 1, further comprising a cutting insert received in the insert seat.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In the following, example embodiments will be described in greater detail and with reference to the accompanying drawings, in which:

[0058] FIG. 1 is an exploded perspective view of a first embodiment of the turning tool according to the present invention;

[0059] FIG. 2 is a perspective view from above of the first the first embodiment of the turning tool;

[0060] FIG. 3 is a perspective view from below of the first the first embodiment of the turning tool;

[0061] FIG. 4 is a top view of the first the first embodiment of the turning tool;

[0062] FIG. 5 is a cross sectional view along V-V of the first embodiment of the turning tool according to FIG. 4;

[0063] FIG. 6 is a cross sectional view along VI-VI of the first embodiment of the turning tool according to FIG. 4, when locked in a first position;

[0064] FIG. 7 is a cross sectional view along VI-VI of the first embodiment of the turning tool according to FIG. 4, when released from the first position;

[0065] FIG. 8 is an exploded perspective view of a second embodiment of the turning tool according to the present invention;

[0066] FIG. 9 is a cross sectional view of the second embodiment of the turning tool corresponding to the view of FIG. 5, when released from the first position;

[0067] FIG. 10 is a cross sectional view of the second embodiment of the turning tool corresponding to the view of FIG. 5, when locked in the first position;

[0068] FIG. 11 is an exploded perspective view of a third embodiment of the turning tool according to the present invention;

[0069] FIG. 12 is a cross sectional view of the third embodiment of the turning tool corresponding to the view of FIG. 5, when released from the first position;

[0070] FIG. 13 is a cross sectional view of the third embodiment of the turning tool corresponding to the view of FIG. 5, when locked in the first position;

[0071] FIG. 14 is a cross sectional view of a fourth embodiment of the turning tool according to the present invention corresponding to the view FIG. 5.

[0072] All the figures are schematic, not necessarily to scale, and generally only show parts which are necessary in order to elucidate the respective embodiments, whereas other parts may be omitted or merely suggested. Unless otherwise indicated, like reference numerals refer to like or corresponding parts in different figures.

DETAILED DESCRIPTION

[0073] With reference to FIGS. 1-7, a first embodiment of a turning tool according to the present invention will be described. The turning tool comprises a tool body 1. The tool body 1 comprises a shaft portion 2 and a head portion 3. In other embodiments, the tool body 1 can comprise a head portion 3 only.

[0074] The tool body 1 has a top surface 4, a first side surface 5, a second side surface 6 and a bottom surface 7. At a front end, the tool body has an insert seat 8 for receiving a cutting insert 9. The insert seat 8 is a recess in the top surface 4 and comprises support surfaces that, when a cutting insert 9 is clamped in the insert seat 8, ensure that the cutting insert 9 is accurately positioned for exposing a cutting edge in a desired location.

[0075] A tool body bore 10 extends into the tool body 1 from the top surface 4 in a downward direction toward the bottom surface 7. The tool body bore 10 is a blind hole and has a circular cross section. The tool body bore 10 is spaced apart from the insert seat 8, or in other words, located outside, in this embodiment rearward in a direction toward the shaft portion 2, of the space occupied by the cutting insert 9. The tool body bore 10 comprises an upward facing shoulder surface 27, which extends circumferentially at an upper end so that the tool body bore 10 has portion with larger diameter at an upper end. An inlet opening 45 for coolant fluid is provided at a lower end of the tool body bore 10. The inlet opening 45 is connectable to an external coolant fluid source through tool body coolant fluid channeling 48.

[0076] The top surface 4 is provided with a depression 36, which is located rearward of the tool body bore 10 in the direction toward the shaft portion 2. A clip 38 is attached in the depression 36 by means of a screw 37.

[0077] The turning tool further comprises a locking mechanism including a tool body side hole 24. The tool body side hole 24 comprises a first portion connecting an opening in the first tool body side surface 5 with the tool body bore 10 and a second portion connecting an opening in the second tool body side surface 6 with the tool body bore 10. Both portions of the tool body side hole 24 have an internal female thread. The tool body side hole 24 has a central longitudinal axis 25 which, as seen in a top view according to FIG. 4, extends transversely across the tool body at an angle c to the extension of the shaft portion 2 of the tool body 1. This angle c is chosen to provide accessibility of the locking mechanism at the head portion 3 and is in this embodiment 65°. In other embodiments the angle can be 45-135°, preferably 60-120°.

[0078] The turning tool further comprises a clamping member 11, which comprises a base body 12 and a clamping arm 13. The clamping arm 13 protrudes from the base body 12 in a forward direction and extends at least a portion over the insert seat 8. The base body has a base body top surface 14 and a base body bottom surface 15.

[0079] A clamping member through hole 16 extends through the clamping member 11 from an opening in the base body top surface 14 to an opening in the base body bottom surface 15. The clamping member through hole 16 has an oval cross section, wherein the long axis extends generally in the direction of the protruding clamping arm 13. The clamping member through hole comprises a downward facing shoulder surface 28, which extends circumferentially at a lower end so that the clamping member through hole 16 has a portion with a larger diameter at a lower end.

[0080] The base body 12 has a flange 39 in an end opposite to the protruding clamping arm 13. The flange 39 extends downward from the base body bottom surface 15 and has a rear surface provided with a groove 40.

[0081] The clamping member is arranged above the tool body 1 so that that the base body bottom surface 14 and the tool body top surface 4 face each other, the clamping member through hole 16 is aligned with the base body bore 10, the clamping arm 13 extends over a portion over the insert seat 8, and the flange 39 is located in the depression 36. The clamping member 11 is attached to the tool body by means of the clip 38 loosely engaging the groove 40.

[0082] The turning tool further comprises a clamping pin 17 which comprises a longitudinal shaft 18 extending along a longitudinal axis 19. At an upper end of the shaft 18, the clamping pin 17 has a head 20, which protrudes radially from the shaft 18. The head 20 is concentric with the longitudinal axis 19 of the shaft 18, which is cylindrical. The head 20 comprises a downward facing clamping surface 21 and a front side surface 55 constituting a portion of a circumferential side surface of the head 20.

[0083] A shaft recess in form of a through hole 26 that extends transverse through the shaft 18 is also part of the locking mechanism. The through hole 26 has an abutment surface in form of an upward facing hole wall 30. The through hole 26 has a central longitudinal axis 56 which intersects the longitudinal axis 19 with an obtuse angle, an entrance opening at the axially lower side of the through hole 26 and exit opening at the axially upper side of the through hole 26.

[0084] The clamping pin 17 comprises a coolant fluid channel 23 that has a first outlet opening 22 and a second outlet opening 22 in the circumferential surface of the head 20. The coolant fluid channel 23 comprises a first internal exit channel 41 and a second internal exit channel 41. The first and second exit channels each have a central longitudinal axis 42 and each extend from an inner position in the head 20 to the respective first and second outlet openings 22. The inner position in the head 20 is a central position located axially above the outlet openings 22. The central longitudinal axis 42 of the first exit channel 41 and the longitudinal axis 19 of the shaft 18 form a sharp angle β of more than 45°, in this embodiment 77°. As seen in an axial end view of the clamping pin 17, c.f. FIG. 4, the central longitudinal axis 42 of the first exit channel intersects the central longitudinal axis of the through hole 26 (and the central longitudinal axis 25 of the first portion of tool body side hole 24) with a predetermined angle cp. This angle is chosen to both provide accessibility of the locking mechanism (which will be described below) and a desired direction of an exiting coolant fluid stream. Usually the angle φ is 70-110°, and in this embodiment 90°. As can be seen, the direction of the exiting coolant fluid stream differs from the extension of the clamping arm 13.

[0085] The coolant fluid channel 23 comprises a longitudinally extending internal portion in the shaft 18, which internal portion has a coolant fluid inlet opening 43 in a downward facing hole wall of the through hole 26.

[0086] The clamping pin 17 is arranged with the shaft 18 thereof extending through the clamping member through hole 16 and into the tool body bore 10, wherein the shaft 18 is axially movably received in the tool body bore 10. The entrance opening of the through hole 26 has an overlap with an inner opening of the first portion of the tool body side hole 24. The shaft, between the lower end and the shaft exit opening of the through hole 26, has an outer surface portion 49 which is located at a distance to the longitudinal axis 19 that is smaller than the radius of the tool body bore. As seen in a cross section comprising the longitudinal axis 19 of the shaft 18 and a central longitudinal axis 25 of the first portion of the tool body side hole 24, the abutment surface in form of the upward facing part of the hole wall 30 forms an angle α of 18° with the central longitudinal axis 25 of the first portion of tool body side hole 24. In other words, this part of the hole wall 30 constitutes an upward facing wedge surface that tapers toward the shaft entrance opening.

[0087] The downward facing clamping surface 21 of the head 20 faces the base body top surface 14 of the clamping member 11. The first outlet opening 22 of the first internal exit channel 41 faces toward the insert seat 8, and the second internal exit channel 41 is closed by a plug 47. A helical spring 29 is arranged around the shaft 18 and abuts, in one end, against the upward facing shoulder surface 27 in the tool body bore 10 and, in the other end, against the downward facing shoulder surface 28 in the clamping member through hole 16. A sealing ring 44 surrounds the shaft 18 and provides a fluid tight seal in the tool body bore 10 while allowing axial movement of the shaft 18.

[0088] The locking mechanism further comprises an actuation bar 31, which comprises an engagement section 32 at an inward end. The outer end of the actuation bar is cylindrical and has an external male thread. The engagement section 32 constitutes a truncated cone with the truncated end pointing inward. At a transition to the truncated cone, the outer end of the actuation bar 31 has a diameter that approximately corresponds the diameter of the entrance opening of the through hole 26 in the shaft 18. The engagement section 32 comprises an engagement surface in form of the outer surface 33 of the truncated cone. The outward end surface of the actuation bar is provided with a hexagonal socket 34 facing away from the truncated cone.

[0089] The actuation bar 31 is mounted in the first portion of the tool body side hole 24, wherein the male thread of the outer end is in engagement with the female thread in the first portion of tool body side hole 24. As seen in a cross section comprising the longitudinal axis 19 of the shaft 18 and a central longitudinal axis 25 of the first portion of tool body side hole 24, the engagement surface in form of the outer cone surface forms an angle α of 18° with the central longitudinal axis 25 of the first portion of tool body side hole 24. In other words, the engaging part of the cone surface constitutes a downward facing wedge surface that tapers inward.

[0090] The hexagonal socket 34 can be reached through the opening in the first side surface 5 of the tool body 1 by means of a hex key 35. The second portion of the tool body side hole 24 is closed by a plug 46.

[0091] The steps of mounting a cutting insert 8 in the insert seat of the first embodiment of the turning tool will now be described mainly with reference to FIGS. 6-7.

[0092] Due to the spring 29 and a play allowed for by the clip 38 in the groove 40, the clamping member is held biased upward to a position wherein a cutting insert 9 can be placed in the insert seat 8 below the clamping arm 13. After placing the cutting insert, the hex key 35 is inserted in the first portion of the tool body side hole 24 and brought into engagement with the socket 34. By rotating the hex key 35 clockwise, the actuation bar 31 is screwed inward in the first portion of the tool body side hole 24. Therein the external male thread of the actuation bar 31 engage with the internal female thread in the first portion of the tool body side hole 24. The outer surface 33 of the truncated cone thereby moves inward and into the through hole 26 in shaft 18 and engages with the abutment surface in form of the upward facing hole wall 30. As the actuation bar 31 is operated and screwed further inward, the outer surface 33 of the truncated cone slides and presses against the abutment surface 30, whereby the shaft 18 is forced to slide axially downward in the tool body bore 10 against the biasing force from the spring 29. Eventually, the downward facing clamping surface 21 of the head 20 engages the base body top surface 14 and forces the base body 12, together with the protruding clamping arm 13, toward the tool body top surface 4. This causes the flange 39 of the base body to slide against a surface in the depression 36 thereby pulling the clamping member 11 rearward in the direction toward the shaft portion 2 of the tool body 1. This relative movement of the clamping member 11 and the shaft 18 is enabled by the oval cross section of the clamping member through hole 16.

[0093] Due to the actuation bar 31 causing the shaft 18 of the clamping pin 17 to slide axially downward in the tool body bore 10, the clamping arm 13 engages the cutting insert 9 in the insert seat 8 and forces the cutting insert 9 downward and rearward against the support surfaces in the insert seat 8. When the clamping pin 17 has reached a first axial position, the cutting insert 9 is clamped in the insert seat 8 and the cutting edge is exposed in the desired location. Furthermore, due to that the portion of the actuation bar 31 with a diameter of approximately the same diameter as the entrance opening of the through hole 26 in the shaft 18 is located in the entrance opening in the first portion, the shaft 18 is releasably locked against axial sliding in both directions. In addition, the clamping pin is advantageously locked against relative rotation to the tool body 1 by positive locking through the actuation bar 31 abutting against the side surface 30 of the through hole 26. Clamping of the cutting insert 9 in the insert seat 8 is advantageous achieved by operating the actuation bar 31 from the side of the turning tool while the clamping pin 11 provides clamping force from above.

[0094] Coolant fluid is provided by connecting the inlet opening 45 at the lower end of the tool body bore 10 to the external coolant fluid source, via the tool body coolant channeling 48. When the shaft 18 is in the first axial position, the inlet opening 45 is located below the lower end of the shaft 18. Coolant fluid flows from the inlet opening 45 upward in the tool body bore 10 and over the outer surface portion 49 with reduced diameter at the shaft 18 and into the through hole 26 through the exit opening thereof. Therein, the coolant fluid is prevented from leaking out of the tool body bore 10 by the plug 46 in the second portion of the tool body side hole 24, by the actuation bar in first portion of the tool body side hole 10, and by the sealing ring 27 on the shaft 18. Instead, the coolant fluid is forced to enter the longitudinally extending internal portion of the coolant fluid channel 23 through the inlet opening 43 in the downward facing hole wall of the through hole 26. From an inner position in the head 20, the coolant fluid flows through the first internal exit channel 41 and exits through the first outlet opening 22 in the head 20.

[0095] In the first axial position, the first outlet opening 22 in the head 20 is located above the base body top surface 4. Due to pressure provided at the coolant fluid source, and the position and angle of the exit channel 41, the exiting coolant fluid is directed to the edge of the cutting insert 9 clamped in the insert seat 8. The extension of the clamping arm 13 can advantageously be chosen according to preferences and independently from the desired direction of the coolant fluid stream.

[0096] The first embodiment of the turning tool described above can advantageously be operated from both the first and the second tool body side surface 5, 6. The tool body side hole 24 including the first and second portions is mirror symmetrical over a central plane, which central plane is located between the first and the second tool body side surfaces and which comprises the longitudinal axis of the shaft 18. The symmetry plane corresponds to the plane shown in FIG. 5. The shaft 18 of the clamping pin 17 is axially slidable in the tool body bore 10 in two angular positions spaced apart by 180° so that, in the first axial position, the shaft entrance opening selectively faces either the first portion of the tool body side hole 24, or the second portion of the tool body side hole 24.

[0097] The first outlet openings 22 is angularly spaced apart from the second outlet opening by 180°. Depending on the angular position, one of the first or the second outlet openings 22 in the head face the cutting insert 9 and the other one faces rearward and is plugged by the plug 47.

[0098] In other embodiments, the first and the second portions of tool body side hole 24 can be angled relative each other so that they are not linearly aligned. The coolant outlet openings 20 in the head 22 of the clamping pin 17 are then spaced apart by the same angle.

[0099] The actuation bar 31 is selectively either movably mounted in the first portion or in the second portion of the tool body side hole 24, wherein, the other of the portions is plugged by the plug 46. Clamping from the second tool body side surface 6 is performed correspondingly to clamping from the first tool body side surface 5 as described above.

[0100] In FIGS. 8-10, and FIGS. 11-13, a second and a third embodiment of the present invention are shown, which differ from the first embodiment mainly by the design of the locking mechanism. Therefore, the first and second embodiments are described with respect to their locking mechanisms and related features only.

[0101] In the second embodiment of FIGS. 8-10, the locking mechanism comprises a tool body side hole 24 of similar design as in the first embodiment. Thus, the tool body side hole 24 comprises a first portion connecting an opening in the first tool body side surface 5 with the tool body bore 10 and a second portion connecting an opening in the second tool body side surface 6 with the tool body bore 10.

[0102] A shaft recess in form of a through hole 26 that extends transverse through the shaft 18 is also part of the locking mechanism. The through hole 26 has a central longitudinal axis which intersects the longitudinal axis 19 with an angle of about 90° and an entrance opening and an exit opening at the same axial distance from the head 20. The through hole 26 has an abutment surface in form of an upward facing hole wall 30.

[0103] The locking mechanism of the second embodiment further comprises an actuation bar 31, which comprises an engagement section 32 at an inner portion. The engagement section comprises an eccentric 50 having a cam surface 51 as engagement surface. The outward end of the actuation bar is cylindrical. The outward end surface of the actuation bar 31 is provided with a hexagonal socket 34 facing away from the eccentric 50.

[0104] Both portions of the tool body side hole 10 have a threaded portion for threadedly receiving a plug 46, and a smooth portion for supporting the outer end of the actuation bar 31. The actuation bar 31 is rotatably supported, wherein the outer end thereof is located in the first portion of the tool body side hole 24 and the engagement section inside the through hole 26. The actuation bar 31 is prevented from moving axially by the eccentric 50 abutting against the side wall of the tool body bore 10.

[0105] In order to clamp the cutting insert 8 in the insert seat 9, the hex key is inserted in the first portion of the tool body side hole and brought into engagement with the socket 34. By rotating the hex key 35 clockwise, the eccentric 51 rotates in the through hole 26 and engages with the abutment surface in form of the upward facing hole wall 30. As the actuation bar 31 is further rotated, the cam surface 51 slides and presses against the abutment surface 30, whereby the shaft 18 is forced to slide axially downward in the tool body bore 10 against the biasing force from the spring 29. Eventually, the clamping pin 17 reaches the first axial position and is realisably locked therein at least due to friction between the cam surface 51 and the upward facing hole wall 30.

[0106] The locking mechanism of the third embodiment as shown in FIGS. 11-13, comprises a tool body bore in form of a through hole 52. The tool body through hole 52 extends from an opening in the tool body top surface 4 to an opening in the tool body bottom surface 7. The locking mechanism further comprises a threaded portion at the lower end of the shaft 18, and a nut 53.

[0107] In order to clamp the cutting insert 8 in the insert seat 9, the clamping pin 17 is pushed downward by pressing against the head 20 until the threaded portion at the lower end of the shaft protrudes past the tool body bottom surface 7. The nut is threaded onto the threads of the threaded portion of the shaft 18. As the nut 53 is further rotated, the nut slides against the bottom surface 7 and the shaft 18 is forced to slide axially downward in the tool body bore 10 against the biasing force from the spring 29. Eventually, the clamping pin 17 reaches the first axial position and is realisably locked therein at least due to friction in the threads, and between the nut 53 and the bottom surface 7.

[0108] In FIG. 14, a fourth embodiment of the turning tool according to the present invention is shown. The fourth embodiment differs from the embodiment shown in FIGS. 1-7, in that the clamping member 11 is an integral part of the tool body 1. The tool body comprises a weakened portion 54 that functions as a living hinge and to bias the clamping member away from the tool body top surface 4. The fourth embodiment is shown with a locking mechanism of the same type as described in connection with the first embodiment. However, the fourth embodiment functions with locking mechanism of the second and third embodiments, too.