Replaceable cutting head, tool holder and morse taper rotary cutting tool with fastening member

Abstract

A cutting tool includes a replaceable cutting head including a front cutting portion and a rear mounting portion and a head through-bore extending therethrough. The mounting portion includes a male coupling member. The male coupling member includes a conical head abutment surface. The cutting tool includes a female coupling member including a conical front retainer abutment surface and an internal thread. The cutting tool includes a fastening member having an external thread. When the cutting tool is in the locked position, the male coupling member is removably retained in the female coupling member by a fastening member located in the through-bore of the head, the fastening member external thread and the retainer internal thread being in threaded engagement with each other. The head abutment surface abuts the front retainer abutment surface, thereby forming a Morse taper coupling between the male coupling component and the female coupling component.

Description

Technical Field

[0001] The subject matter of the present application relates to a type of rotary cutting tool in which a replaceable cutting head having a male coupling member is removably held in a female coupling member of a tool holder by means of a friction fit coupling mechanism. More particularly, it relates to such tools in which the coupling mechanism has a mechanical taper, and still further particularly, in which the mechanical taper is of the Morse taper type, and still further particularly, in which the coupling mechanism has additional fastening means. Background Art

[0002] Rotary cutting tools may be provided with a coupling mechanism for releasably holding a replaceable cutting head within a tool holder by means of fastening means. For example, an instance of such a rotary cutting tool is disclosed in US7,431,543, which shows a machine reamer comprising a base and an interchangeable reamer head assembled on the base. The reamer head is clamped by means of a tension rod into a complementary face side blade seat of the base in a conical shoulder to provide the necessary coaxiality. The tension rod has complementary polygonal sections which extend through an axial polygonal opening of the indexable head to ensure good rotational capture.

[0003] Another instance is US7,004,692, which shows a cutting head, a screw member and a tool shank. The screw member is threadedly engaged with the tool shank. The cutting head is centered relative to the tool shank, wherein a conical portion of the cutting head is located in a conical front portion of the tool shank. The cutting head has a head opening with a plurality of locking wings, and the screw member has a plurality of clamping wings. The rotational coupling between the cutting head and the screw member is obtained by the engagement of the clamping wings on the screw member and a stop projecting axially forward from a locking surface of the locking wings. That is, torque is transmitted from the tool shank to the head via the clamping wings on the screw member.

[0004] Other rotary cutting tools may be provided with a friction fit coupling mechanism of the Morse taper type. For example, an instance of such a rotary cutting tool is disclosed in US2,407,471A, which shows an adapter having a tool receiving socket and a rotary tool having a tapered shank for it. The tapered shank ends in a tang for engagement with a drill, while facets eliminate rotation of the tool within the socket. Typically, a hammer is used to knock the tapered shank into the tool receiving socket until they are held by friction.

[0005] The object of the subject matter of the present application is to provide a coupling mechanism for a replaceable cutting head in a tool holder which is particularly suitable for rotary cutting tools with a small outer cutting diameter. Summary of the Invention

[0006] According to a first aspect of the subject matter of the present application, there is provided a replaceable cutting head for rotary cutting operations, having a head longitudinal axis that defines opposite forward and rearward directions, and opposite rotary forward and rotary rearward directions, wherein the rotary forward direction is the cutting direction, and the replaceable cutting head comprises:

[0007] a front portion forming a cutting part and a rear portion forming a mounting part; and

[0008] opposite head front and rear surfaces and a head peripheral surface extending therebetween, the head front surface being at the cutting part and the head rear surface being at the mounting part;

[0009] a head through-hole that includes a through-hole peripheral surface extending around a through-hole central axis and intersecting the head front and rear surfaces; wherein:

[0010] the mounting part includes a male coupling member projecting rearward from a head base surface that extends transversely relative to the head longitudinal axis and defines a boundary between the cutting part and the mounting part; and

[0011] the male coupling member includes a conical head abutment surface configured for a Morse taper coupling mechanism.

[0012] According to yet another aspect of the subject matter of the present application, there is also provided a tool holder having a holder longitudinal axis, which includes a female coupling member extending rearward from a holder front surface that extends transversely relative to the holder longitudinal axis, and the female coupling member includes:

[0013] a conical front holder abutment surface configured for a Morse taper coupling mechanism; and

[0014] a holder internal thread located rearward of the front holder abutment surface.

[0015] According to yet another aspect of the subject matter of the present application, there is also provided a rotary cutting tool, which includes:

[0016] a replaceable cutting head of the type described above;

[0017] a tool holder of the type described above; and

[0018] a fastening member that is elongated along a fastening member longitudinal axis, the fastening member including a fastening member clamping portion and a fastening member shank portion axially offset from the fastening member clamping portion along the fastening member longitudinal axis, the fastening member clamping portion including a clamping surface that tapers inwardly in a direction from the fastening member clamping portion toward the fastening member shank portion, and the fastening member shank portion including a fastening member external thread; wherein:

[0019] The rotary cutting tool is adjustable between a release position and a locked position, wherein, in the locked position:

[0020] The male coupling member is removably held in the female coupling member by a fastening member located in the through-hole of the head, and the external thread of the fastening member and the internal thread of the retainer are thread-engaged with each other; and

[0021] The head abutment surface abuts against the front retainer abutment surface, thereby forming a Morse taper coupling between the male coupling member and the female coupling member.

[0022] It is understood that the above is a generalization, and the features described below can be applied to the subject matter of the present application in any combination. For example, any one of the following features can be applied to a replaceable cutting head, a tool holder, or a rotary cutting tool:

[0023] The head abutment surface can taper inwardly in a backward direction at a head cone angle. The head cone angle can be in the range of 2.8° ≤ 2α ≤ 3.16°.

[0024] In particular, the head cone angle can be in the range of 2.9° ≤ 2α ≤ 3.06°.

[0025] The through-hole of the head can include a clamping portion receiving portion and a shank portion receiving portion axially offset from the clamping portion receiving portion, and the shank portion receiving portion extends between the clamping portion receiving portion and the rear surface of the head. The clamping portion receiving portion can include at least one support surface that tapers inwardly in a backward direction.

[0026] The clamping portion receiving portion can extend to the front surface of the head.

[0027] The through-hole of the head can include at least two radially extending through-hole widening portions that extend from the rear surface of the head to the clamping portion receiving portion.

[0028] The clamping portion receiving portion can include at least two clamping wing recesses, each clamping wing recess merging with a corresponding through-hole radial widening portion and being in front of the rotation of the corresponding through-hole radial widening portion around the longitudinal axis of the head. The clamping portion receiving portion can include at least two support surfaces, each support surface being formed by a portion of a corresponding clamping wing recess.

[0029] The through-hole of the head can include exactly two through-hole widening portions diametrically opposite each other around the central axis of the through-hole. The clamping portion receiving portion can include exactly two clamping wing recesses diametrically opposite each other around the central axis of the through-hole.

[0030] The head abutment surface has a head cone height measured in the direction along the longitudinal axis of the head. The head abutment surface has a maximum head cone diameter. The head cone height can be greater than the maximum head cone diameter.

[0031] In particular, the head cone height can be greater than 1.5 times the maximum head cone diameter.

[0032] The mounting portion has a mounting portion height measured in a direction along the longitudinal axis of the head between the rear surface of the head and the base surface of the head. The head cone height can be greater than 80% of the mounting portion height.

[0033] The cutting portion has a cutting portion height measured in a direction along the longitudinal axis of the head between the front surface of the head and the base surface of the head. The mounting portion height can be greater than the cutting portion height.

[0034] The mounting portion height can be greater than twice the cutting portion height.

[0035] The male coupling member can be without external threads and tangs and a square driver.

[0036] At least one support surface can be located entirely in front of the base surface of the head.

[0037] The front retainer abutment surface can taper inwards towards the retainer internal thread at a retainer cone angle. The retainer cone angle can be in the range of 2.8° ≤ 2γ ≤ 3.16°.

[0038] In particular, the retainer cone angle can be in the range of 2.9° ≤ 2γ ≤ 3.06°.

[0039] The tool holder can include a retainer peripheral surface that extends around the longitudinal axis of the retainer and defines the boundary of the front surface of the retainer. The tool holder can include a coolant channel that opens into the retainer peripheral surface.

[0040] The retainer peripheral surface can include a front retainer peripheral surface and a rear retainer peripheral surface and an intermediate retainer peripheral surface extending therebetween. The front retainer peripheral surface is closer to the front surface of the retainer than both the intermediate retainer peripheral surface and the rear retainer peripheral surface. The front retainer peripheral surface has a diameter that can be less than the diameter of the rear retainer peripheral surface. The coolant channel can open at least partially into the intermediate retainer peripheral surface.

[0041] The tool holder can further include a rear support portion having a rear retainer abutment surface that extends around the longitudinal axis of the retainer.

[0042] The front retainer abutment surface has a retainer cone height measured in a direction along the longitudinal axis of the retainer. The front retainer abutment surface has a maximum retainer cone diameter. The retainer cone height can be greater than the maximum retainer cone diameter.

[0043] In particular, the retainer cone height can be greater than 1.5 times the maximum retainer cone diameter.

[0044] The retainer internal thread has an internal thread length measured in a direction along the longitudinal axis of the retainer. The internal thread length may be less than the retainer cone height.

[0045] In the locked position, at least one clamping surface may abut at least one support surface.

[0046] The fastening member may be integrally formed and have an integral one-piece structure.

[0047] In the locked position, the head base surface may be spaced from the retainer front surface.

[0048] The rotary cutting tool may be a reamer.

[0049] The head through-hole may include at least two through-hole widening portions extending from the head rear surface to the clamping portion receiving portion. The clamping portion receiving portion may include at least two clamping wing recesses, each clamping wing recess merging with a corresponding through-hole radial widening portion and being in front of the corresponding through-hole radial widening portion in rotation about the head longitudinal axis. The clamping portion receiving portion may include at least two support surfaces, each support surface being formed by a portion of a corresponding clamping wing recess. The fastening member clamping portion may include at least two fastening member clamping wings extending radially outward relative to the longitudinal axis of the fastening member. The fastening member clamping portion may include at least two clamping surfaces, each clamping surface being formed by a portion of a corresponding fastening member clamping wing. Each of the at least two fastening member clamping wings may be located in a corresponding clamping wing recess. In the locked position, each of the at least two clamping surfaces may abut a corresponding support surface.

[0050] Each of the at least two clamping wing recesses may include a recess side surface extending radially relative to the longitudinal axis of the retainer and facing in a rotationally backward direction. Each of the at least two fastening member clamping wings may include two opposing wing side surfaces extending radially relative to the longitudinal axis of the fastening member. In the locked position, for any and all fastening member clamping wings, one of the two opposing wing side surfaces may face in a rotationally forward direction. Further, in the locked position, the rotationally backward-facing recess side surface of each of the at least two clamping wing recesses may abut the corresponding rotationally forward-facing wing side surface.

[0051] The fastening member shank portion may include an elongated fastening member neck portion extending between the fastening member clamping portion and the fastening member external thread. The fastening member neck portion has a fastening member neck height measured in a direction along the longitudinal axis of the fastening member. The fastening member external thread has an external thread length measured in a direction along the longitudinal axis of the fastening member. The fastening member neck height may be greater than the external thread length.

[0052] The head through-hole may include exactly two through-hole widening portions that are diametrically opposed to each other about the through-hole central axis. The clamping portion receiving portion may include exactly two clamping wing recesses that are diametrically opposed to each other about the through-hole central axis. The fastening member clamping portion may include exactly two fastening member clamping wings that are diametrically opposed to each other about the longitudinal axis of the fastening member.

[0053] The tool holder may further include a rear support portion having a rear holder abutment surface extending about the longitudinal axis of the holder. The fastening member shank portion may include at least two fastening member resilient pins that are angularly spaced about the longitudinal axis of the fastening member, the at least two fastening member resilient pins being flexible in the radial direction and positioned further from the fastening member clamping portion than the external thread of the fastening member. In the locked position, the at least two fastening member resilient pins may be elastically deformed against the rear holder abutment surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] For a better understanding of the present application and to show how it may be put into practice, reference will now be made to the accompanying drawings, in which:

[0055] Figure 1 is a perspective view of a rotary cutting tool;

[0056] Figure 2 is Figure 1 an exploded perspective view of the rotary cutting tool shown in ;

[0057] Figure 3 is Figure 1 and Figure 2 a perspective view of the replaceable cutting head shown in ;

[0058] Figure 4 is Figure 3 a side view of the replaceable cutting head shown in, showing the hidden head through-hole;

[0059] Figure 5 is a cross-sectional view of the replaceable cutting head taken along line V-V in ; Figure 4 ;

[0060] Figure 6 is Figure 3 a rear view of the replaceable cutting head shown in ;

[0061] Figure 7 is Figure 3 a front view of the replaceable cutting head shown in ;

[0062] Figure 8 is a cross-sectional view of the replaceable cutting head taken along line VIII-VIII in ; Figure 7 ;

[0063] Figure 9is a cross-sectional view taken along line IX-IX in Figure 7 ;

[0064] Figure 10 is Figure 1 and Figure 2 a top view of the tool holder shown in

[0065] Figure 11 is a cross-sectional view taken along line XI-XI in Figure 10 of the tool holder shown;

[0066] Figure 12 is Figure 11 a detail of

[0067] Figure 13 is Figure 1 and Figure 2 a perspective view of the fastening member shown in

[0068] Figure 14 is Figure 13 a side view of the fastening member shown in

[0069] Figure 15 is Figure 13 a top view of the fastening member shown in

[0070] Figure 16 is Figure 13 a bottom view of the fastening member shown in

[0071] Figure 17 is Figure 1 and Figure 2 a detailed longitudinal cross-sectional view of the rotary cutting tool shown in the rotary cutting tool in the locked position;

[0072] Figure 18 is Figure 1 and Figure 2 a radial cross-sectional view taken along line XVIII-XVIII in Figure 17 of the rotary cutting tool shown; and

[0073] Figure 19 is Figure 1 and Figure 2 a radial cross-sectional view taken along line XIX-XIX in Figure 17 of the rotary cutting tool shown.

[0074] It will be appreciated that, for simplicity and clarity of illustration, the components shown in the figures are not necessarily drawn to scale. For example, for clarity, the dimensions of some of the components may be exaggerated relative to other components, or several physical components may be included in one functional block or component. Where considered appropriate, reference numerals may be repeated between the figures to indicate corresponding or similar components. DETAILED DESCRIPTION

[0075] In the following description, various aspects of the subject matter of the present application will be described. For purposes of explanation, specific configurations and details are set forth in full to provide a thorough understanding of the subject matter of the present application. However, it will also be apparent to those skilled in the art that the subject matter of the present application may be practiced without the specific configurations and details provided herein.

[0076] First, note Figure 1 and Figure 2 , which show a rotary cutting tool 20 of the type used for reaming operations in accordance with an embodiment of the subject matter of the present application. The rotary cutting tool 20 includes a replaceable cutting head 22 having a head longitudinal axis A, and the replaceable cutting head 22 rotates about the head longitudinal axis A, defining opposite rotational forward directions R F and a rotational backward direction R R . The rotational forward direction R F is the cutting direction. The head longitudinal axis A also defines opposite forward directions D F and a backward direction D R . In other words, the head longitudinal axis A extends in the forward D F to backward D R direction. The replaceable cutting head 22 may typically be made of carbide. The rotary cutting tool 20 also includes a tool holder 24. The tool holder 24 may typically be made of steel. The replaceable cutting head 22 may be removably held in the tool holder 24 by means of a friction fit coupling mechanism and a fastening member. Such a coupling may possibly be advantageous for other types of rotary cutting operations (such as, for example, milling or drilling) in addition to those recited above.

[0077] It should be recognized that the use of the terms "forward" and "backward" throughout the specification and claims refers to the relative positions in the Figure 4 , 8 and 9 in which the head longitudinal axis A is respectively toward the left and right directions. It should also be recognized that the use of the terms "rotationally forward" and "rotationally backward" throughout the specification and claims refers to the relative positions in the Figure 5 and Figure 7 in which the rotations about the head longitudinal axis A are respectively counterclockwise and clockwise directions.

[0078] Now refer to Figures 3 to 9。The replaceable cutting head 22 has a front portion that forms a cutting portion 26 and a rear portion that forms a mounting portion 28. That is, the cutting portion 26 is disposed forward, while the mounting portion 28 is disposed rearward. According to some embodiments of the subject matter of the present application, the cutting portion 26 may be adjacent to the mounting portion 28.

[0079] The replaceable cutting head 22 includes an opposite head front surface 56 and a head rear surface 58 and a head peripheral surface 60 extending therebetween. The head front surface 56 is located at the cutting portion 26 and generally faces in the forward direction D F upward. The head rear surface 58 is located at the mounting portion 28 and generally faces in the rearward direction D R upward. The head peripheral surface 60 extends about a head longitudinal axis A. According to some embodiments of the subject matter of the present application, the head rear surface 58 may be perpendicular to the head longitudinal axis A.

[0080] According to some embodiments of the subject matter of the present application, the replaceable cutting head 22 may be integrally formed to have a monolithic structure. This provides the advantage that the replaceable cutting head 22 does not have a removable cutting blade (not shown). Such removable cutting blades need to be replaced regularly, and this can be a time-consuming process. There is also a possibility that, for example, a threaded screw (not shown) that can be used to releasably hold the removable cutting blade in the replaceable cutting head 22 can be misplaced and / or lost during the replacement operation.

[0081] Referring to Figure 3 , the cutting portion 26 includes at least one peripheral cutting edge 30. In this non-limiting example shown in the figure, there may be exactly six peripheral cutting edges. The peripheral cutting edges 30 define an outer cutting diameter O. The outer cutting diameter O may be equal to or less than 7.6 mm. Each peripheral cutting edge 30 is formed at the intersection of a peripheral relief surface 32 and a peripheral rake surface 34. The peripheral relief surface 32 is located behind (i.e., rearward) of the rotation of the peripheral cutting edge 30, while the peripheral rake surface 34 is located in front (i.e., forward) of the rotation of the peripheral cutting edge 30. Generally, the peripheral rake surface 34 faces in the rotation forward direction R F upward. The orientation of the peripheral cutting edges 30 (and the peripheral rake surface 34 and the peripheral relief surface 32) allows for the performance of metal cutting operations. According to some embodiments of the subject matter of the present application, the cutting portion 26 may include at least one groove 36 for discharging chips (not shown) generated during the cutting operation. One groove 36 is associated with each peripheral cutting edge 30. As seen in the figure, the cutting portion 26 includes a plurality of circumferentially arranged cutting segments 31, each cutting segment 31 including, in the rotation forward direction R F in succession, a rear relief surface 32, a cutting edge 30, a rake surface 34, and a groove 36.

[0082] Specifically referring to Figure 4 , the mounting portion 28 includes a male coupling member 38 that projects rearwardly from the head base surface 40. The head base surface 40 extends transversely with respect to the head longitudinal axis A and defines a boundary between the cutting portion 26 and the mounting portion 28. That is, the cutting portion 26 is formed in front of the head base surface 40, while the mounting portion 28 is formed behind the head base surface 40. According to some embodiments of the subject matter of the present application, the male coupling member 38 may be rigid. The head base surface 40 may be perpendicular to the head longitudinal axis A. Note that the male coupling member 38 may be bounded in the rearward direction D R by the head rear surface 58. The male coupling member 38 may not have external threads and shanks and square drivers. Additionally, the male coupling member 38 may not have pull studs.

[0083] Referring again to Figure 4 , the cutting portion 26 has a cutting portion height H2 measured in the direction along the head longitudinal axis A between the head front surface 56 and the head base surface 40. The mounting portion 28 has a mounting portion height H4 measured in the direction along the head longitudinal axis A between the head rear surface 58 and the head base surface 40. According to some embodiments of the subject matter of the present application, the mounting portion height H4 may be greater than the cutting portion height H2. Preferably, the mounting portion height H4 may be greater than twice the cutting portion height H2.

[0084] The male coupling member 38 includes a head adjacent surface 54 that extends circumferentially and that extends around the head longitudinal axis A. The head adjacent surface 54 faces radially outward. The head adjacent surface 54 tapers inwardly in the rearward direction D R at a head cone angle 2α. That is, the head adjacent surface 54 has a radially outward-facing conical shape, where the head cone angle 2α is an interior angle. The head adjacent surface 54 is configured for a Morse taper coupling mechanism. According to some embodiments of the subject matter of the present application, the head adjacent surface 54 may be frustoconical. The head cone angle 2α may be in the range of 2.8° ≤ 2α ≤ 3.16° (i.e., a typical Morse taper cone angle). Preferably, the head cone angle 2α may be in the range of 2.9° ≤ 2α ≤ 3.06°. In other words, the head adjacent surface 54 may define a taper angle α in the range of 1.45° ≤ α ≤ 1.53° with respect to the head longitudinal axis A (the taper angle α being half of the cone angle 2α). In some embodiments, the head cone angle 2α may be equal to 2.98°. Note that the head adjacent surface 54 is intended to abut a corresponding surface on the tool holder 24 when the rotary cutting tool 20 is in the locked position, as will be described hereinafter.

[0085] It should be appreciated that the use of the terms "radially inward / inward" and "radially outward / outward" throughout the specification and claims refers to Figures 4 to 9and the relative positions in the vertical directions toward and away from the respective axes with respect to the head longitudinal axis A and / or the retainer longitudinal axis C in FIGS. 10 to 12. It should also be recognized that the term "cone angle" as used throughout the specification refers to the angle formed by the tapered surface of the cone in a longitudinal cross-section. Note that the term "longitudinal cross-section" refers to a cross-section taken along a plane containing the longitudinal axis.

[0086] The conical head abutment surface 54 has a maximum head cone diameter D max which is the maximum diameter of the conical head abutment surface 54. The conical head abutment surface 54 has a minimum head cone diameter D min which is the minimum diameter of the conical head abutment surface 54.

[0087] Referring to Figure 4 、 8 and 9, in some embodiments of the subject matter of the present application, the head abutment surface 54 may intersect the head rear surface 58 via a head chamfer surface 62 to form a chamfer. That is, the head chamfer surface 62 may extend between the head abutment surface 54 and the head rear surface 58 and be adjacent to the head abutment surface 54 and the head rear surface 58.

[0088] In some embodiments of the subject matter of the present application, the head abutment surface 54 may intersect the head base surface 40 via a head fillet surface 63 to form a concave fillet. That is, the head fillet surface 63 may extend between the head abutment surface 54 and the head base surface 40 and be adjacent to the head abutment surface 54 and the head base surface 40.

[0089] The head abutment surface 54 has a head cone height H1 measured in the direction along the head longitudinal axis A. In some embodiments of the subject matter of the present application, the head cone height H1 may be greater than the maximum head cone diameter D max . In particular, the head cone height H1 may be greater than the maximum head cone diameter D max by 1.5 times. Thus, compared with other known tapered connectors (such as the tapered connector disclosed in US7,004,692), the tapered contact area between the male and female connector components is larger. The head cone height H1 may be less than 5 times the maximum head cone diameter D max . In particular, the head cone height H1 may be less than 2.5 times the maximum head cone diameter D max . The head cone height H1 may be greater than 80% of the mounting portion height H4. The head cone height H1 may be greater than the outer cutting diameter O.

[0090] Generally referring to Figures 2 to 9 , the replaceable cutting head 22 includes a head through-hole 42 which extends through the cutting portion 26 and the mounting portion 28. In Figure 4In [description], the head through-hole 42 is hidden and is thus indicated by a dashed line. The head through-hole 42 is configured for a fastening member to be inserted therethrough, as described subsequently in the specification. The head through-hole 42 includes a through-hole peripheral surface 44 that extends around a through-hole central axis E. Generally speaking, the through-hole peripheral surface 44 faces towards the through-hole central axis E. The through-hole peripheral surface 44 intersects with the head front surface 56 and the head rear surface 58. That is to say, the head through-hole 42 opens to the head front surface 56 and the head rear surface 58 (at the head front hole opening 57 and the head rear hole opening 59 respectively). According to some embodiments of the subject matter of the present application, the head front hole opening 57 and the head rear hole opening 59 may be intersected by the head longitudinal axis A. The through-hole central axis E may coincide with the head longitudinal axis A. Note that the head through-hole 42 may not have internal threads.

[0091] According to some embodiments of the subject matter of the present application, the head through-hole 42 may include a clamping portion receiving portion 64 and a shank portion receiving portion 66. The shank portion receiving portion 66 is axially offset from the clamping portion receiving portion 64 (along the head longitudinal axis A). The shank portion receiving portion 66 may extend between the clamping portion receiving portion 64 and the head rear surface 58. The clamping portion receiving portion 64 may extend to the head front surface 56. The clamping portion receiving portion 64 may include at least one support surface 52 that tapers (inclines) inwardly in the backward direction D R thereby. Thus, the at least one support surface 52 faces radially inwardly. The shank portion receiving portion 66 may transition into the clamping portion receiving portion 64 at the at least one support surface 52 in the forward direction D F therein. The at least one support surface 52 may be entirely located in front of the head base surface 40. That is to say, the at least one support surface 52 may be entirely located in the cutting portion 26.

[0092] Referring to Figures 5 to 7, in some embodiments of the subject matter of the present application, the head through - hole 42 may include a through - hole central portion 46 that extends between the head front surface 56 and the head rear surface 58 along the head longitudinal axis A. The head through - hole 42 is non - cylindrical. That is, the head through - hole 42 has a non - constant radial cross - section along the through - hole central axis E. In particular, the head through - hole 42 may include at least two radially extending through - hole widening portions 48 that extend from the head rear surface 58 to the clamping - part receiving portion 64. The at least two through - hole widening portions 48 may extend to the head front surface 56. The at least two through - hole widening portions 48 may merge with the through - hole central portion 46 and be radially outwardly disposed from the through - hole central portion 46. The at least two through - hole widening portions 48 may be identical and have rotational symmetry about the through - hole central axis E. In this non - limiting example shown in the figure, the head through - hole 42 includes exactly two through - hole widening portions 48 that are diametrically opposite each other about the through - hole central axis E. The head through - hole 42 may further include at least two through - hole narrowing portions 49 that extend from the head rear surface 58 to the clamping - part receiving portion 64. Each pair of adjacent through - hole narrowing portions 49 is angularly spaced apart by a corresponding through - hole widening portion 48. The number of through - hole narrowing portions 49 may match the number of through - hole widening portions 48. Thus, two through - hole narrowing portions 49 may be diametrically opposite each other and have 180° rotational symmetry about the through - hole central axis E.

[0093] Referring to Figure 5 and Figure 7 , in some embodiments of the subject matter of the present application, the clamping - part receiving portion 42 may include at least two clamping - wing recesses 50. The at least two clamping - wing recesses 50 are designed to receive the respective clamping wings of the fastening member 92, as described subsequently in the specification. The number of clamping - wing recesses 50 may match the number of through - hole widening portions 48. The at least two clamping - wing recesses 50 may merge with the through - hole central portion 46 and be radially outwardly disposed from the through - hole central portion 46. Each clamping - wing recess 50 may merge with a corresponding through - hole radially widening portion 48 and extend rotationally forward (about the head longitudinal axis A) from the corresponding through - hole radially widening portion 48. Each clamping - wing recess 50 may be angularly aligned with a corresponding through - hole narrowing portion 49 and be axially located in front of the corresponding through - hole narrowing portion 49. In this non - limiting example shown in the figure, the head through - hole 42 includes exactly two clamping - wing recesses 50 that are diametrically opposite each other about the through - hole central axis E and have 180° rotational symmetry about the through - hole central axis E.

[0094] In some embodiments of the subject matter of the present application, each clamping - wing recess 50 may include a recess side surface 53 that extends radially with respect to the retainer longitudinal axis C. The recess side surface 53 faces in the rotationally - backward direction R R above. The clamping - part receiving portion 64 may include at least two support surfaces 52, each support surface 52 being formed by a portion of a corresponding clamping - wing recess 50. Referring again to Figure 5 andFigure 7 Each support surface 52 may extend from a respective recess side surface 53 to an adjacent through-hole widening 48. At least two clamping wing recesses 50 may be identical and have rotational symmetry about the through-hole central axis E.

[0095] Another aspect of the subject matter of the present application relates to the tool holder 24. Now refer to Figures 10 to 12 The tool holder 24 has a holder longitudinal axis C. According to some embodiments of the subject matter of the present application, the tool holder 24 may include a holder peripheral surface 74 that extends around the holder longitudinal axis C and defines the boundary of the holder front surface 70.

[0096] According to some embodiments of the subject matter of the present application, the holder peripheral surface 74 may include a front holder peripheral surface 76 and a rear holder peripheral surface 78, and an intermediate holder peripheral surface 77 extending therebetween. The front holder peripheral surface 76 may be closer to the holder front surface 70 than both the intermediate holder peripheral surface 77 and the rear holder peripheral surface 78. The front holder peripheral surface 76 and the rear holder peripheral surface 78 are located on different imaginary coaxial cylinders. The front holder peripheral surface 76 may have a diameter smaller than the diameter of the rear holder peripheral surface 78. The intermediate holder peripheral surface 77 may be radially outwardly inclined from the front holder peripheral surface 76 to the rear holder peripheral surface 78.

[0097] Refer to Figure 12 The tool holder 24 includes a female coupling member 68 that extends rearward from the holder front surface 70. The holder front surface 70 extends transversely with respect to the holder longitudinal axis C. According to some embodiments of the subject matter of the present application, the holder front surface 70 may be perpendicular to the holder longitudinal axis C. The female coupling member 68 includes a holder internal thread 72 that extends along the holder longitudinal axis C. The holder internal thread 72 has an internal thread length LI measured in the direction of the holder longitudinal axis C.

[0098] The female coupling member 68 includes two support portions, a front support portion 80 and a rear support portion 82, with the front support portion 80 located in front of the rear support portion 82. The front support portion 80 and the rear support portion 82 are located on both sides of the holder internal thread 72. In other words, the holder internal thread 72 is located between the front support portion 80 and the rear support portion 82.

[0099] The front support portion 80 includes a front retainer abutment surface 84 that extends around the retainer longitudinal axis C. The front retainer abutment surface 84 is located in front of the retainer internal thread 72 (in other words, the retainer internal thread 72 is located behind the front retainer abutment surface 84). The retainer internal thread 72 is spaced apart from the retainer front surface 70 by at least the front retainer abutment surface 84. The front retainer abutment surface 84 faces inwardly relative to the retainer longitudinal axis C. The front retainer abutment surface 84 tapers inwardly in the (backward) direction toward the retainer internal thread 72 at a retainer cone angle 2γ. That is, the front retainer abutment surface 84 has a radially inward-facing conical shape, where the retainer cone angle 2γ is an exterior angle. The front retainer abutment surface 84 is configured for a Morse taper coupling mechanism. In some embodiments of the subject matter of the present application, the front retainer abutment surface 84 may be frustoconical. The retainer cone angle 2γ may be in the range of 2.8° ≤ 2γ ≤ 3.16°. Preferably, the retainer cone angle 2γ may be in the range of 2.9° ≤ 2γ ≤ 3.06°. In other words, the front retainer abutment surface 84 may define a taper angle γ relative to the retainer longitudinal axis C in the range of 1.45° ≤ γ ≤ 1.53°. In some embodiments, the retainer cone angle 2γ may be equal to 2.98°.

[0100] Referring Figure 12 , the conical front retainer abutment surface 84 has a maximum retainer cone diameter d max , which is the maximum diameter of the conical front retainer abutment surface 84. The conical front retainer abutment surface 84 has a minimum retainer cone diameter d min , which is the minimum diameter of the conical front retainer abutment surface 84.

[0101] The front retainer abutment surface 84 has a retainer cone height H3 as measured in the direction along the retainer longitudinal axis C. The internal thread length LI may be less than the retainer cone height H3. The retainer cone height H3 may be greater than the maximum retainer cone diameter d max . In particular, the retainer cone height H3 may be greater than 1.5 times the maximum retainer cone diameter d max . The retainer cone height H3 may be less than 5 times the maximum retainer cone diameter d max . In particular, the retainer cone height H3 may be less than 2.5 times the maximum retainer cone diameter d max .

[0102] In some embodiments of the subject matter of the present application, the rear support portion 82 may include a rear retainer abutment surface 88 that extends around the retainer longitudinal axis C. The rear retainer abutment surface 88 may be cylindrical.

[0103] In some embodiments of the subject matter of the present application, the tool holder 24 may include at least one coolant passage 79. The at least one coolant passage 79 may open to the holder peripheral surface 74 at a coolant passage outlet 79a. The coolant passage outlet 79a is configured to direct coolant towards the peripheral cutting edge 30. Preferably, the at least one coolant passage 79 may open at least partially to the intermediate holder peripheral surface 77. In this non-limiting example shown in the figures, the tool holder 24 includes exactly four coolant passages 79 and exactly four coolant passage outlets 79a that are evenly distributed around the holder longitudinal axis C. The at least one coolant passage 79 may be spaced apart from the female member 68. At least a portion of the at least one coolant passage 79 may be radially outside the female member 68.

[0104] Another aspect of the subject matter of the present application relates to a rotary cutting tool 20 that includes a replaceable cutting head 22 and a tool holder 24 as defined hereinabove. Referring Figures 13 to 16 , the rotary cutting tool 20 further includes a fastening member 92. The fastening member 92 is elongate along a fastening member longitudinal axis F. The fastening member 92 includes a fastening member clamping portion 94 and a fastening member shank portion 98. The fastening member clamping portion 94 and the fastening member shank portion 98 are axially offset from each other (relative to the fastening member longitudinal axis F). In some embodiments of the subject matter of the present application, the fastening member 92 may be integrally formed and have a monolithic single-piece structure. The fastening member 92 may typically be made of steel.

[0105] In some embodiments of the subject matter of the present application, the fastening member clamping portion 94 may include a clamping surface 102 that tapers (inclines) inwardly in a direction from the fastening member clamping portion 94 towards the fastening member shank portion 98. Thus, the clamping surface 102 faces radially outward relative to the fastening member longitudinal axis F.

[0106] In some embodiments of the subject matter of the present application, the fastening member clamping portion 94 may include at least two fastening member clamping wings 100 that extend radially outward relative to the fastening member longitudinal axis F. That is, the fastening member 92 may have a "bayonet" configuration. In this non-limiting example shown in the figures, the fastening member clamping portion 94 may include exactly two fastening member clamping wings 100 that are diametrically opposed to each other around the fastening member longitudinal axis F.

[0107] According to some embodiments of the subject matter of the present application, each fastening member clamping wing 100 may include two opposing wing side surfaces 104a, 104b that extend radially relative to the fastening member longitudinal axis F. The two wing side surfaces 104a, 104b face away from each other. The fastening member clamping portion 94 may include at least two clamping surfaces 102, each clamping surface 102 being formed by a portion of a corresponding fastening member clamping wing 100. The clamping surfaces 102 may extend between the two wing side surfaces 104a, 104b.

[0108] The fastening member shank portion 98 includes a fastening member external thread 96. The fastening member external thread 96 has an external thread length LE measured in the direction of the fastening member longitudinal axis F. According to some embodiments of the subject matter of the present application, the fastening member external thread 96 may be interrupted (i.e., discontinuous, not shown).

[0109] According to some embodiments of the subject matter of the present application, the fastening member shank portion 98 may include an elongated fastening member neck portion 99 that extends between the fastening member clamping portion 94 and the fastening member external thread 96. The fastening member neck portion 99 has a fastening member neck height N measured in the direction along the fastening member longitudinal axis F. Different from, for example, US 7,004,692 where a screw member has a hollow portion (formed by a through hole for providing coolant to a coolant outlet), in the sense that there is no through hole, the fastening member 92 of the present invention is solid. Therefore, the length of the fastening member 92 can be increased without the risk of weakening. In this regard, note that the fastening member neck height N may be greater than the external thread length LE. In particular, the fastening member neck height N may be greater than twice the external thread length LE.

[0110] According to some embodiments of the subject matter of the present application, the fastening member shank portion 98 may include at least two fastening member resilient pins 106 that are angularly spaced about the fastening member longitudinal axis F. The at least two fastening member resilient pins 106 are flexible in the radial direction. The at least two fastening member resilient pins 106 may be located at the rear end portion of the fastening member 92 and are thus farther from the fastening member clamping portion 94 than the fastening member external thread 96. The at least two fastening member resilient pins 106 may be spaced apart by a fastening member pin clearance 108. In this non-limiting example shown in the figure, the fastening member 92 includes exactly two fastening member resilient pins 106 that are diametrically opposed to each other about the fastening member longitudinal axis F.

[0111] The rotary cutting tool 20 is capable of being adjusted between a release position and a locking position. In the release position of the rotary cutting tool 20, as Figure 2 shown, the rotary cutting tool 20 is unassembled and the male coupling member 38 is located outside the female coupling member 68.

[0112] The assembly of the rotary cutting tool 20 can be accomplished by performing the following steps. According to the first assembly method, the fastening member shank portion 98 is inserted into the female coupling member 68. The fastening member external thread 96 is rotated within the retainer internal thread 72 in the backward rotation direction R R to cause the fastening member external thread 96 and the retainer internal thread 72 to initially thread-engage with each other. In this position, for any and all of the fastening member clamping wings 100, one of the two opposing wing side surfaces 104a, 104b faces upward in the forward rotation direction R F Next, the replaceable cutting head 22 is placed above the fastening member clamping portion 94 and oriented such that at least two through-hole widening portions 48 are aligned with at least two fastening member clamping wings 100. Then, the replaceable cutting head 22 is moved toward the tool retainer 24, where at least two fastening member clamping wings 100 pass through at least two through-hole widening portions 48, allowing the male coupling member 38 to be inserted into the female coupling member 68 until the head abutment surface 54 is in initial contact with the retainer abutment surface 84. The replaceable cutting head 22 is rotated in the backward rotation direction R R (optionally, by a key, not shown) until each fastening member clamping wing 100 is located within a clamping wing recess 50 and each rotation-rearward facing recess side surface 53 abuts the corresponding rotation-forward facing wing side surface 104a. The replaceable cutting head 22 is further rotated, and by means of each rotation-rearward facing recess side surface 53 that abuts the corresponding rotation-forward facing wing side surface 104a, the fastening member 92 is also rotated, which in turn further thread-engages the fastening member external thread 96 with the retainer internal thread 72, pulling the fastening member 92 into the female coupling member 68 until each clamping surface 102 abuts the corresponding support surface 52. Further rotation of the replaceable cutting head 22 (and thus the fastening member 92) causes the fastening member 92 to advance the male coupling member 38 of the replaceable cutting head 22 into the female coupling member 68 of the tool retainer 24 until the conical head abutment surface 54 abuts the conical front retainer abutment surface 84, and ultimately forms a Morse taper coupling between the male coupling member 38 and the female coupling member 68, defining the locked position of the rotary cutting tool 22. As the male coupling member is advanced into the female coupling member, the surface pressure between the two parts increases. The resulting friction prevents slipping, causing the taper to self-retain. In this regard, note (unlike, for example, US7,004,692) that there is no axial stop preventing the male coupling member 36 from being inserted into the female coupling member 68. Also note that the fastening member 92 pushes the male coupling member into the female member in a controlled and precise manner, unlike, for example, a hammer.

[0113] In the locked position of the rotary cutting tool 20, the male coupling member 38 is removably held in the female coupling member 68 by a fastening member 92 located in the head through-hole 42. The external thread 96 of the fastening member and the internal thread 72 of the retainer are threadedly engaged with each other. The head longitudinal axis A, the retainer longitudinal axis C, and the fastening member longitudinal axis F all coincide (i.e., are aligned) with each other. In some embodiments of the subject matter of the present application, at least one clamping surface 102 may abut at least one support surface 52. The head base surface 40 may be spaced apart from the retainer front surface 70. That is, the head base surface 40 does not contact the retainer front surface 70. At least two fastening member resilient pins 106 may be elastically deformed against the rear retainer abutment surface 88. In the "bayonet" configuration of the fastening member 92, each of at least two clamping surfaces 102 may abut a corresponding support surface 52. Each of the rotationally rearward-facing cavity side surfaces 53 of at least two clamping wing cavities 50 may abut a corresponding rotationally forward-facing wing side surface 104a.

[0114] Unlike US 7,004,692 in which the conical abutment surface is mainly used for centering purposes, the conical abutment surface of the present invention provides most of the torque transmission from the tool holder 24 to the cutting head 22 by means of a Morse taper connection. Accordingly, less force and stress are applied to the fastening member (in particular, the fastening member clamping wing 100). This is particularly advantageous for rotary cutting tools having a small outer cutting diameter (i.e., equal to or less than 7.6 mm), where the fastening member is correspondingly small, which a) makes it more likely to break, b) is less effective for securing the head in the cavity, and c) is less effective in transmitting torque to the head.

[0115] While the subject matter of the present invention has been described in a certain degree of particularity, it should be understood that various variations and modifications can be made without departing from the spirit or scope of the present invention as claimed hereinafter.

Claims

1. A replaceable cutting head (22) for rotary cutting operations, having a head longitudinal axis (A), the head longitudinal axis (A) defining opposite forward directions (D F ) and backward directions (D R ), and opposite rotary forward directions (R F ) and rotary backward directions (R R ), wherein the rotary forward direction (R F ) is the cutting direction, the replaceable cutting head (22) Comprising: A front portion forming a cutting portion (26) and a rear portion forming a mounting portion (28); And Opposite head front surface (56) and head rear surface (58) and a head peripheral surface (60) extending therebetween, the head front surface (56) being located at the cutting portion (26) and the head rear surface (58) being located at the mounting portion (28); A head through-hole (42) including a through-hole peripheral surface (44) extending around a through-hole central axis (E) and intersecting the head front surface (56) and the head rear surface (58); wherein: The mounting portion (28) includes a male coupling member (38) protruding rearward from a head base surface (40), the head base surface (40) extending transversely with respect to the head longitudinal axis (A) and defining a boundary between the cutting portion (26) and the mounting portion (28); and The male coupling member (38) includes a conical head abutment surface (54) configured for a Morse taper coupling mechanism.

2. The replaceable cutting head (22) according to claim 1, wherein The head adjacent surface (54) tapers inwards at a head cone angle (2α) in the said backward direction (D R ). The head cone angle (2α) is in the range of 2.8° ≤ 2α ≤ 3.16°.

3. The replaceable cutting head (22) according to claim 2, Wherein, The head cone angle (2α) is in the range of 2.9° ≤ 2α ≤ 3.06°.

4. The replaceable cutting head (22) according to any one of claims 1 to 3, Wherein: The head through-hole (42) includes: A clamping portion receiving portion (64) and a shank portion receiving portion (66) axially offset from the clamping portion receiving portion (64), the shank portion receiving portion (66) extending between the clamping portion receiving portion (64) and the head rear surface (58); and The clamping portion receiving part (64) includes at least one support surface (52) that tapers inwardly in the rearward direction (D R ).

5. The replaceable cutting head (22) according to claim 4, Wherein: The clamping portion receiving portion (64) extends to the head front surface (56).

6. The replaceable cutting head (22) according to claim 4 or 5, Wherein: The head through-hole (42) includes at least two radially extending through-hole widening portions (48) extending from the head rear surface (58) to the clamping portion receiving portion (64).

7. The replaceable cutting head (22) according to claim 6, Wherein: The clamping portion receiving portion (64) includes: At least two clamping wing cavities (50), each clamping wing cavity (50) merging with a corresponding through-hole radial widening portion (48) and being rotationally in front of the corresponding through-hole radial widening portion (48) around the head longitudinal axis (A); and At least two support surfaces (52), each support surface (52) being formed by a portion of a corresponding clamping wing cavity (50).

8. The replaceable cutting head (22) according to claim 7, Wherein: The head through-hole (42) includes exactly two through-hole widening portions (48) diametrically opposite each other around the through-hole central axis (E); and The clamping part receiving portion (64) includes exactly two clamping wing recesses (50) diametrically opposed to each other about the central axis (E) of the through hole.

9. The replaceable cutting head (22) according to any one of claims 1 to 7, wherein: The head abutment surface (54) has a head cone height (H1) measured in the direction along the longitudinal axis (A) of the head; The head adjacent surface (54) has a maximum head cone diameter (D max ); and The height (H1) of the head cone is greater than the maximum head cone diameter (D max ).

10. The replaceable cutting head (22) according to claim 9, wherein: The height (H1) of the head cone is greater than 1.5 times the maximum head cone diameter (D max ).

11. The replaceable cutting head (22) according to claim 9 or 10, wherein: The mounting portion (28) has a mounting portion height (H4) measured in the direction along the longitudinal axis (A) of the head between the rear surface (58) of the head and the base surface (40) of the head; and The head cone height (H1) is greater than 80% of the mounting portion height (H4).

12. The replaceable cutting head (22) according to claim 11, wherein: The cutting portion (26) has a cutting portion height (H2) measured in the direction along the longitudinal axis (A) of the head between the front surface (56) of the head and the base surface (40) of the head; and The mounting portion height (H4) is greater than the cutting portion height (H2).

13. The replaceable cutting head (22) according to claim 12, wherein, The mounting portion height (H4) is greater than twice the cutting portion height (H2).

14. The replaceable cutting head (22) according to any one of claims 1 to 13, wherein, The male coupling member (38) has no external thread, shank and square driver.

15. The replaceable cutting head (22) according to any one of claims 1 to 14, wherein, The at least one support surface (52) is entirely located in front of the base surface (40) of the head.

16. A tool holder (24) having a holder longitudinal axis (C), comprising a female coupling member (68) extending rearward from a holder front surface (70) that extends transversely with respect to the holder longitudinal axis (C), the holder front surface (70) comprising: A conical front holder abutment surface (84) configured for a Morse taper coupling mechanism; and A holder internal thread (72) located behind the front holder abutment surface (84).

17. The tool holder (24) according to claim 16, wherein: The front holder abutment surface (84) tapers inwardly towards the holder internal thread (72) at a holder cone angle (2γ); The holder cone angle (2γ) is in the range of 2.8° ≤ 2γ ≤ 3.16°.

18. The tool holder (24) according to claim 17, wherein, The holder cone angle (2γ) is in the range of 2.9° ≤ 2γ ≤ 3.06°.

19. The tool holder (24) according to any one of claims 16 to 18, wherein: The tool holder (24) includes: A retainer peripheral surface (74) that extends around the longitudinal axis (C) of the retainer and defines the boundary of the front surface (70) of the retainer; and A coolant passage (79) that opens into the retainer peripheral surface (74).

20. The tool holder (24) according to claim 19, wherein: The retainer peripheral surface (74) includes a front retainer peripheral surface (76) and a rear retainer peripheral surface (78) and an intermediate retainer peripheral surface (77) extending therebetween, the front retainer peripheral surface (76) being closer to the front surface (70) of the retainer than both the intermediate retainer peripheral surface (77) and the rear retainer peripheral surface (78); The front retainer peripheral surface (76) has a diameter smaller than the diameter of the rear retainer peripheral surface (78); and The coolant passage (79) opens at least partially into the intermediate retainer peripheral surface (77).

21. The tool holder (24) according to claim 19 or 20, the tool holder (24) further including a rear support portion (82) having a rear retainer abutment surface (88) that extends around the longitudinal axis (C) of the retainer.

22. The tool holder (24) according to any one of claims 16 to 21, wherein The front retainer abutment surface (84) has a retainer cone height (H3) as measured in the direction along the longitudinal axis (C) of the retainer; The front retainer abutment surface (84) has a maximum retainer cone diameter (d max ); and The height (H3) of the retainer cone is greater than the maximum retainer cone diameter (d max ).

23. The tool holder (24) according to claim 22, wherein: The height (H3) of the retainer cone is greater than 1.5 times the maximum retainer cone diameter (d max ).

24. The tool holder (24) according to claim 22 or 23, wherein: The internal thread (72) of the retainer has an internal thread length (LI) as measured in the direction along the longitudinal axis (C) of the retainer; The internal thread length (LI) is less than the retainer cone height (H3).

25. A rotary cutting tool (20) that includes: A replaceable cutting head (22) according to any one of claims 1 to 15; A tool holder (24) according to any one of claims 16 to 24; and A fastening member (92) that is elongated along a fastening member longitudinal axis (F), the fastening member (92) including a fastening member clamping portion (94) and a fastening member shank portion (98) axially offset from the fastening member clamping portion (94) along the fastening member longitudinal axis (F), the fastening member clamping portion (94) including a clamping surface (102) that tapers inwardly in a direction from the fastening member clamping portion (94) toward the fastening member shank portion (98), the fastening member shank portion (98) including an external thread (96) of the fastening member; wherein: The rotary cutting tool (20) is adjustable between a release position and a locking position, wherein, in the locking position: The male coupling member (38) is removably held in the female coupling member (68) by the fastening member (92) located in the head through-hole (42), and the external thread (96) of the fastening member and the internal thread (72) of the retainer are threadedly engaged with each other; and The head abutment surface (54) abuts the front retainer abutment surface (84), thereby forming a Morse taper connection between the male coupling member (38) and the female coupling member (68).

26. The rotary cutting tool (20) according to claim 25, In the locked position: The at least one clamping surface (102) abuts the at least one support surface (52).

27. The rotary cutting tool (20) according to claim 25 or 26, Wherein, The fastening member (92) is integrally formed and has an integral one-piece structure.

28. The rotary cutting tool (20) according to any one of claims 25 to 27, Wherein, In the locked position, the head base surface (40) is spaced apart from the retainer front surface (70).

29. The rotary cutting tool (20) according to any one of claims 25 to 28, Wherein, The rotary cutting tool (20) is a reamer.

30. The rotary cutting tool (20) according to any one of claims 25 to 29, Wherein: The head through-hole (42) includes at least two through-hole widening portions (48) extending from the head rear surface (58) to the clamping portion receiving portion (64); The clamping portion receiving portion (64) includes: At least two clamping wing cavities (50), each clamping wing cavity (50) merging with a corresponding through-hole radial widening portion (48) and being in front of the corresponding through-hole radial widening portion (48) in rotation around the head longitudinal axis (A); and At least two support surfaces (52), each support surface (52) being formed by a part of the corresponding clamping wing cavity (50); The fastening member clamping portion (94) includes at least two fastening member clamping wings (100) extending radially outward relative to the fastening member longitudinal axis (F); The fastening member clamping portion (94) includes at least two clamping surfaces (102), each clamping surface (102) being formed by a part of the corresponding fastening member clamping wing (100); Each of the at least two fastening member clamping wings (100) is located in a corresponding clamping wing cavity (50); and In the locked position: Each of the at least two clamping surfaces (102) abuts a corresponding support surface (52).

31. The rotary cutting tool (20) according to claim 30, Wherein: Each of the at least two clamping wing cavities (50) includes a cavity side surface (53) which extends radially with respect to the holder longitudinal axis (C) and faces upwardly in the rotation backward direction (R R ). Each of the at least two fastening member clamping wings (100) includes two opposite wing side surfaces (104a, 104b) extending radially relative to the fastening member longitudinal axis (F); In the locked position: For any and all fastening member clamping wings (100), one of the two opposing wing side surfaces (104a) faces in the rotation forward direction (R F ) above; and The rotation-facing cavity side surface (53) of each of the at least two clamping wing cavities (50) abuts the corresponding rotation-facing wing side surface (104a).

32. The rotary cutting tool (20) according to claim 30 or 31, wherein: the shank portion (98) of the fastening member includes an elongated fastening member neck portion (99) extending between the fastening member clamping portion (94) and the fastening member external thread (96); the fastening member neck portion (99) has a fastening member neck height (N) measured in the direction along the longitudinal axis (F) of the fastening member; the fastening member external thread (96) has an external thread length (LE) measured in the direction along the longitudinal axis (F) of the fastening member; and the fastening member neck height (N) is greater than the external thread length (LE).

33. The rotary cutting tool (20) according to any one of claims 30 to 32, wherein: the head through-hole (42) includes exactly two through-hole widening portions (48) diametrically opposed to each other around the through-hole central axis (E); and the clamping portion receiving portion (64) includes exactly two clamping wing recesses (50) diametrically opposed to each other around the through-hole central axis (E); and the fastening member clamping portion (94) includes exactly two fastening member clamping wings (100) diametrically opposed to each other around the longitudinal axis (F) of the fastening member.

34. The rotary cutting tool (20) according to any one of claims 30 to 33, wherein: the tool holder (24) further includes a rear support portion (82) having a rear holder abutment surface (88) extending around the longitudinal axis (C) of the holder; the shank portion (98) of the fastening member includes: at least two fastening member resilient pins (106) angularly spaced apart around the longitudinal axis (F) of the fastening member, the at least two fastening member resilient pins (106) being flexible in the radial direction and positioned further away from the fastening member clamping portion (94) than the fastening member external thread (96); and in the locked position: the at least two fastening member resilient pins (106) are elastically deformed against the rear holder abutment surface (88).

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