INSERT ADAPTOR FOR PARTING OFF

Abstract

An insert adaptor for parting off including an adaptor index axis and parallel adaptor first and second sides connected by an adaptor peripheral surface which extends peripherally around the adaptor. The adaptor peripheral surface is formed with at least three pockets and bearing surfaces extending between the pockets. Each of the pockets comprises resilient upper and lower clamp surfaces.

Claims

1. An insert adaptor for parting off having an adaptor index axis and comprising: parallel adaptor first and second sides which are free of projecting bearing surfaces and are connected by an adaptor peripheral surface which extends peripherally around the adaptor; the adaptor index axis extending through the center of the first and second sides; wherein the adaptor peripheral surface is formed with a plurality of pockets configured for resilient clamping and bearing surfaces extending between the pockets; and wherein the insert adaptor has a material volume of greater than 50% of an imaginary cylinder encompassing the insert adapter.

2. The insert adaptor according to claim 1, wherein said plurality of pockets are at least three pockets.

3. The insert adaptor according to claim 1, wherein, in a side view of the insert adaptor, the bearing surfaces are straight bearing surfaces extending between the pockets.

4. The insert adaptor according to claim 3, wherein, in a side view of the insert adaptor, each straight bearing surface comprises a recessed portion located adjacent to one of the pockets, a non-recessed portion, and a transition portion connecting the recessed and non-recessed portion.

5. The insert adaptor according to claim 1, wherein each of the bearing surfaces are planar.

6. The insert adaptor according to claim 1, wherein the pockets are equally circumferentially spaced about the adaptor peripheral surface.

7. The insert adaptor according to claim 1, wherein one or both of the upper and lower clamp surfaces has a ridge shape.

8. The insert adaptor according to claim 1, wherein exactly one of the upper and lower clamp surfaces comprises two contact areas separated by a relief recess.

9. The insert adaptor according to claim 1, wherein each pocket is formed with an insert stopper surface.

10. The insert adaptor according to claim 1, further being formed with a solid construction devoid of elasticity grooves.

11. The insert adaptor according to claim 1, wherein the first and second sides are planar.

12. The insert adaptor according to claim 1, wherein said volume is greater than 55% and less than 75% of the volume of the imaginary cylinder.

13. The insert adaptor according to claim 1, further being formed with a single central screw hole opening out to the adaptor first and second sides.

14. The insert adaptor according to claim 1, further being formed with a plurality of equally circumferentially spaced screw holes opening out to the adaptor first and second sides.

15. The insert adaptor according to claim 14, wherein the number of screw holes is equal to the number of the pockets of the insert adaptor.

16. The insert adaptor according to claim 1, further being formed with a non-central fastening configuration comprising a plurality of screw holes for clamping the insert adaptor to a tool.

17. The insert adaptor according to claim 16, wherein the screw holes are equally circumferentially spaced from each other.

18. The insert adaptor according to claim 1, further comprising a release aperture associated with each of the pockets.

19. A tool assembly for parting off comprising: a tool holder, an insert adaptor according to claim 1 mounted to an adaptor recess of the tool holder's tool head; and an insert mounted to the insert adaptor; wherein the insert comprises a cutting edge which is the only cutting edge of the tool assembly positioned for operational use.

20. The tool assembly according to claim 19, wherein, in an operational position, a forward most bearing surface of said bearing surfaces, which extends below the insert, extends essentially perpendicular to an operational direction DO.

21. The tool assembly according to claim 19, wherein said cutting edge has a cutting edge thickness measured parallel with the adaptor index axis IA and the insert adaptor comprising an adaptor thickness measured parallel with the adaptor index axis IA; and wherein the adaptor thickness is smaller than the cutting edge thickness.

22. The tool assembly according to claim 19, wherein the tool holder further comprising a coolant channel which extends underneath the adaptor recess and opens out at a forward most portion of an adaptor recess, the coolant channel being aligned with an adaptor plane bisecting the insert adaptor first and second sides.

23. The tool assembly according to claim 19, wherein the insert adaptor is further being formed with a non-central fastening configuration comprising a plurality of screw holes for clamping the insert adaptor to a tool, and each screw hole has a dual function as a release aperture.

24. The tool assembly according to claim 19, wherein the insert adaptor is formed with a screw hole offset from a corresponding tool hole in the adaptor recess, to bias the insert adaptor in a desired direction.

25. The tool assembly according to claim 19, wherein said cutting edge is the only cutting edge of said insert.

26. The tool assembly according to claim 19, wherein said cutting edge has a thickness is greater than the remainder of the insert's thickness measured along the same axis.

27. The tool assembly according to claim 19, wherein said insert has an elongate shape.

28. The tool assembly according to claim 19, wherein said tool holder has an elongated tool shank.

29. The tool assembly according to claim 28, wherein an operational direction that the tool holder is parallel with an elongation direction of the elongated tool shank.

30. The tool assembly according to claim 28, wherein the tool shank has a quadrilateral cross-section.

31. The tool assembly according to claim 19, wherein said adaptor recess comprises at least one adaptor seating surface protuberance.

32. The tool assembly according to claim 19, wherein said tool head comprises first and second tool bearing surfaces protruding from the tool holder along a periphery of the adaptor recess.

33. The tool assembly according to claim 32, wherein the first and second tool bearing surfaces are the only tool bearing surfaces of the tool holder, such that the insert adaptor contacts the tool holder only via three regions thereof, namely one of the sides of the insert adaptor, and exactly two straight bearing surfaces.

34. The tool assembly according to claim 32, wherein at least one of the first and second tool bearing surfaces is formed with two contact areas separated by a relief recess.

35. The tool assembly according to claim 19, wherein said tool head comprises a concave recessed tool head front surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0070] For a better understanding of the subject matter of the present application, and to show how the same may be carried out in practice, reference will now be made to the accompanying drawings, in which:

[0071] FIG. 1A is a side view of a portion of a cutting tool assembly;

[0072] FIG. 1B is an upper view of the portion of the cutting tool assembly in FIG. 1A;

[0073] FIG. 1C is a front view of the portion of the cutting tool assembly in FIGS. 1A and 1B;

[0074] FIG. 2A is an upper view an insert adaptor of the cutting tool assembly in FIGS. 1A to 1C, and a single insert held in a pocket of the insert adaptor;

[0075] FIG. 2B is a side view of the insert adaptor in FIG. 2A;

[0076] FIG. 2C is an enlarged front view of a portion of the insert adaptor in FIG. 2A, including a pocket thereof;

[0077] FIG. 2D is an enlarged side view of the portion of the insert adaptor in FIG. 2C, including a pocket thereof;

[0078] FIG. 2E is an enlarged side view of an alternative pocket of an insert adaptor;

[0079] FIG. 2F is an enlarged side view of a yet another alternative pocket of an insert adaptor;

[0080] FIG. 3A is a side view of a tool holder of the cutting tool assembly in FIGS. 1A to 1C; [0081] FIG. 3B is an upper view of the tool holder in FIG. 3A; [0082] FIG. 3C is a front view of the tool holder in FIGS. 3A and 3B; [0083] FIG. 4 is a cross section view taken along line IV-IV in FIG. 3B; [0084] FIG. 5 is a partially sectioned schematic side view of a screw of the cutting tool assembly in FIGS. 1A to 1C; [0085] FIG. 6A is a side view of a portion of an alternative cutting tool assembly; [0086] FIG. 6B is an upper view of the portion of the cutting tool assembly in FIG. 6A; [0087] FIG. 6C is a front view of the portion of the cutting tool assembly in FIGS. 6A and 6B; [0088] FIG. 7A is an upper view of an insert adaptor of the cutting tool assembly in FIGS. 6A to 6C, and a single insert held in a pocket of the insert adaptor; [0089] FIG. 7B is a side view of the insert adaptor and insert in FIG. 7A; [0090] FIG. 8A is a side view of a tool holder of the cutting tool assembly in FIGS. 6A to 6C; [0091] FIG. 8B is an upper view of the tool holder in FIG. 8A; and [0092] FIG. 8C is a front view of the tool holder in FIGS. 8A and 8B.

DETAILED DESCRIPTION

[0093] Reference is made to FIGS. 1A and 1B, illustrating a tool assembly 10 configured for parting off operations.

[0094] The tool assembly 10 can comprise an insert adaptor 12, an insert 14 (FIG. 2B; such insert designation may additionally or alternatively be designated with a suffix e.g., first, second, third and fourth pockets 14A, 14B, 14C, 14D, 14E; further designations below are also made in such manner) mounted to the insert adaptor 12, a tool holder 16, and a screw 18 used to secure the insert adaptor 12 to the tool holder 16.

[0095] Referring now also to FIGS. 2A and 2B, the insert adaptor 12 can comprise parallel adaptor first and second sides 20A, 20B connected by an adaptor peripheral surface 22, and can have an adaptor index axis I.sub.A extending through the center of the adaptor first and second sides 20A, 20B.

[0096] The adaptor peripheral surface 22 is formed with pockets 24 (also suffixed, e.g., first, second, third, fourth and fifth pockets 24A, 24B, 24C, 24D, 24E). The pockets 24 can preferably be equally circumferentially spaced about the adaptor index axis I.sub.A.

[0097] Preferably, each of the pockets 24, as shown in the present example, are identical, and, for the sake of succinctness only, a generic pocket designated 24 shown in FIGS. 2C and 2D will be described in detail.

[0098] The pocket 24 can open out to a front end 26, and can further comprise a rear end 28, and opposing upper and lower clamp surfaces 30, 32 extending between the front and rear ends 26, 28.

[0099] A clamping gap 34 can be defined between the upper and lower clamp surfaces 30, 32.

[0100] An ejection gap 36 can be defined between the clamping gap 34 and the rear end 28, and in the present example the pocket 24 comprises a single concave end portion 38 at the rearmost end thereof

[0101] In FIG. 2C, it is shown that both the upper and lower clamp surfaces 30, 32 have a ridge shape, i.e. a convex shape each of which preferably have an apex 40A, 40B aligned with an adaptor plane P.sub.A (FIG. 2C) bisecting the first and second sides 20A, 20B. It will be understood that the opposite shape, i.e. a crest shape, is also one of other possibilities.

[0102] In the side view of FIG. 2D, it is shown that one of the clamp surfaces, in this example the upper clamp surface 30 is straight (stated differently, follows a linear path in a side view such as that shown). Whereas the other clamp surface, in this example the lower clamp surface 32 comprises two contact areas 42A, 42B separated by a relief recess 42C, for more secure mounting of the insert 14 (not shown in FIG. 2D).

[0103] The ejection gap 36 can also constitute a relief portion, by being further enlarged than the clamping gap 34. More precisely, the enlargement referred to is that shown in a side view (FIG. 2D) in that a minimum first distance L.sub.1 between, and perpendicular to, the upper and lower clamp surfaces 30, 32 is smaller than a parallel minimum second distance L.sub.2 of the ejection gap 36 to the first distance L.sub.1.

[0104] The pocket 24 can further be formed with an insert stopper surface 44. In FIG. 2D the insert stopper surface 44 is located along the periphery of the insert adaptor 12 between the front end 26 and the upper clamp surface 30. The insert stopper surface 44 is transverse, although not necessarily perpendicular to the upper clamp surface 30. An intermediary surface 45 may or may not be present between the insert stopper surface 44 and a bearing surface 52 adjacent thereto (see for comparison, e.g. FIG. 2F).

[0105] In FIG. 2E an alternative insert stopper surface 44 is exemplified as located at a rear end 28 of a pocket 24. The insert stopper surface 44 being essentially perpendicular to an elongation direction D.sub.E of the pocket 24. However, as shown in FIG. 2F, even an insert stopper surface 44 is located at a rear end 28 of a pocket 24 need not be perpendicular to an elongation direction D.sub.E of the pocket 24 (in this case directed slightly downward along direction D.sub.D). To accommodate different insert shapes, a pocket 24 may include an additional insert stopper surface 44. In some embodiments, there may be two ejection or relief gaps 36, 36.

[0106] Reverting to FIGS. 2A and 2B, to facilitate fastening of the insert adaptor 12 to the tool holder 16, the insert adaptor 12 can be formed with a fastening configuration 46 in the center thereof. Preferably, the fastening configuration 46 is a single screw hole 48 opening out to the first and second sides 20A, 20B. The screw hole 48 can comprise a taper portion 50 tapering inwardly from the first and second sides 20A, 20B.

[0107] The adaptor peripheral surface 22 can be formed with a straight bearing surfaces 52 (also suffixed, e.g., first, second, third, fourth and fifth pockets bearing surfaces 52A, 52B, 52C, 52D, 52E), i.e. in a side view (e.g. FIG. 2B) extending between the pockets 24. Preferably, the bearing surfaces 52 can also be planar. The bearing surfaces 52 are in the present example preferably arranged to form a basic pentagonal shape.

[0108] As noted above, the insert adaptor 12 can have a particularly solid construction excluding the insert pockets 24 and the screw hole 48. To quantify an imaginary circle I.sub.C (FIG. 2B) can be extended to an imaginary cylinder with an insert adaptor thickness T.sub.A (FIG. 2A) which encompasses the insert adaptor 12. The insert adaptor 12 can preferably have a material volume of greater than 50% of a volume of said imaginary cylinder.

[0109] The imaginary circle I.sub.C can further define an adaptor circumscribing diameter D.sub.AC.

[0110] As also shown in FIG. 2A, the insert 14 comprises a single cutting edge 53 having a cutting edge thickness T.sub.1, measured parallel with the adaptor index axis I.sub.A, which is greater than the remainder of the insert 14, when measured parallel with the adaptor index axis I.sub.A. The cutting edge thickness T.sub.1 is greater than an adaptor thickness T.sub.A, measured parallel with the adaptor index axis I.sub.A, as required for parting off operations. The insert 14 can have an elongate shape as shown in FIG. 2B.

[0111] Referring to FIGS. 3A to 3C, the tool holder 16 can comprise an elongated tool shank 54 and a tool head 56 extending therefrom.

[0112] The tool shank 54 can preferably be formed with a coolant inlet 57 that can be optionally closed with a plug 58 (FIG. 1A) when not in use.

[0113] The tool head 56 can comprise an adaptor recess 60 configured for receiving the insert adaptor 12 therein. The adaptor recess 60 can comprise at least one adaptor seating surface protuberance 62 which protrudes further than a remainder 63 of the adaptor recess 60 for stable contact with one of the insert adaptor's first and second sides 20A, 20B.

[0114] The tool head 56 can further comprise first and second tool bearing surfaces 64A, 64B protruding from the tool holder 16 along a periphery of an adaptor recess 60.

[0115] In the side view of FIG. 3A, it is shown that the first tool bearing surface 64A can be straight (stated differently, follows a linear path). Whereas the other clamp surface, in this example the second tool bearing surface 64B comprises two contact areas 65A, 65B separated by a relief recess 65C, for more secure mounting of the insert adaptor 12.

[0116] Imaginary tool bearing surface lines I.sub.T1, I.sub.T2 extending from the first and second tool bearing surfaces 64A, 64B can form an acute tool bearing surface angle A.sub.1.

[0117] The tool head 56 can further comprise a back-up bearing surface 66.

[0118] At each end of the of the first and second tool bearing surfaces 64A, 64B and the back-up bearing surface 66, relief portions 67 (also suffixed, e.g., first, second, third, fourth relief portions 67A, 67B, 67C, 67D) are formed to provide a gap between the second, third, fourth and fifth inserts 14B, 14C, 14D, 14E (or more precisely the cutting edges thereof) and the tool head 56.

[0119] The tool head 56 can further comprise a tool hole 68. The tool hole 68 can be internally threaded and also a through-hole (i.e. extending completely through the tool head 56). Preferably, the tool hole 68 can be configured to bias the insert adaptor 12 in a biasing direction D.sub.B towards the back-up bearing surface 66 for particularly strong clamping.

[0120] Referring to FIG. 1B, a recessed tool head front surface 69, which is preferably concave, can facilitate cutting depth. It will be understood that the cutting depth in this particular example extends to the first cutting depth D.sub.C1 limited by the screw 18 projecting from the insert adaptor 12, but could potentially, in other embodiments, extend to a second cutting depth D.sub.C2 corresponding to a length to a rearmost portion of the tool head front surface 69.

[0121] Referring to FIG. 5, the screw 18 which has optionally preferred features is shown.

[0122] The screw 18 comprises a head portion 70 and a threaded shank portion 72, and can have an overall screw length L.sub.S.

[0123] The head portion 70 can have a frustoconical shape as shown to reduce projection shown in FIG. 1B, and can comprise a tool-receiving configuration 74.

[0124] A frustoconical surface 73 of the head portion 70 can form an angle A.sub.2 of 45??5?.

[0125] The shank portion 72 can comprise a threaded sub-portion 75 and a threadless sub-portion 76.

[0126] The shank portion 72 can have a shank length L.sub.S1 at least three times greater than an adaptor thickness A.sub.T of the insert adaptor. Preferred values being recited above. It will be clarified that the shank length L.sub.S1 referred to only the part of the shank portion 72 comprising threading (for gripping the tool holder 16), and does not include non-threaded portions as exemplified by a second shank length L.sub.S2, or a third shank length L.sub.S3 which is measured along the threadless sub-portion 76.

[0127] The shank portion 72 can further comprise a tool-receiving configuration 78.

[0128] Referring to FIG. 4, a coolant channel 80 originating from the coolant inlet 57 (FIG. 3A) can extend under the adaptor recess 60. In order to achieve flow to a narrow slit region during a parting off operation, the coolant channel 80 can open out at a coolant outlet 82 (see also FIGS. 1B and 3B) aligned with and directly underneath a forwardmost portion of the adaptor recess 60, and directed to an active cutting edge (FIG. 1B). The coolant channel 80, in other words, requires a curved path to achieve the desired coolant outlet 82 position. Preferably there is only a single coolant outlet 82. As shown, the coolant channel 80 can, using traditional channel forming methods such as drilling, comprise a number of straight coolant channel sections 84A, 84B, 84C, 84D. Although, under more recent additive manufacturing methods, the coolant channel 80 could be formed with one or more curved sections (not shown).

[0129] To further detail operation: one, or preferably each of the pockets 24 can have an insert 14 mounted thereto before the insert adaptor 12 is in the clamped position shown in FIGS. 1A to 1C (preferably the inserts 14 are mounted while the insert adaptor 12 is not mounted at all to the tool holder 16).

[0130] The insert 14 can be mounted to the pocket 24 by sliding it from the front end 26 of the pocket 24 towards the rear end 28 thereof which forces the opposing upper and lower clamp surfaces 30, 32 to slightly separate, with the elasticity of the insert adaptor 12 causing them to resiliently clamp the insert 14 therebetween (notably the insert 14 is configured to preferably contact only the upper clamp surface 30 and the two contact areas 42A, 42B of the lower clamp surface 32).

[0131] A tool, such as a soft face hammer (not shown) would typically be used for mounting. The pockets 24 may have a relative rigidity for resilient type pockets in view of the insert adaptor 12 preferably being free of elasticity grooves, which are omitted in preferred embodiments order to maintain sufficient insert adaptor constructional strength for ultra-thin parting off operations.

[0132] Thereafter, the insert adaptor 12 can be clamped to the tool holder 16 via fastening of the screw 18. In an operational position the insert adaptor 12 contacts the tool holder 16 only via the first side 20A and exactly two of the straight bearing surfaces (e.g. the second and fourth bearing surface 52B, 52D. Notably, a gap 86 is typically designed between the insert adaptor 12 and the back-up bearing surface 66.

[0133] In FIGS. 1A to 1C, only the first insert 14A is in an operational position to part-off a workpiece (not shown) typically by the tool assembly 10 being moved in the operational direction D.sub.O shown.

[0134] After the first insert 14A is worn, either it can be replaced by being ejected (e.g. a portion of an ejection tool (not shown) can be inserted through the ejection gap 34 to eject the first insert 14A by a step of levering the ejection tool against the rear end 28, and a different insert which is not shown can be inserted as described above) or by indexing of the insert adaptor 12, until each of the inserts 14 are successively worn and then all replaced.

[0135] The insert adaptor 12 can be either removed completely for indexing or preferably a step of loosening the screw 18 (via either of the receiving configurations 74, 78) while maintaining partial attachment of the screw 18 to the tool head 56 is carried out. Subsequent to such loosening, the insert adaptor 12 is moved away from the tool head 56 such that it can be rotated without contacting the first and second tool bearing surfaces 64A, 64B and rotated to bring an adjacent insert 14 into an operative position. Subsequently, the insert adaptor 12 is moved back into contact with the tool head 56 and clamped via fastening of the screw 18. Such indexing being user friendly due to the extremely low likelihood of falling parts.

[0136] Reference is made to FIGS. 6A to 8C, an alternative tool assembly 110 is shown to comprising of an insert adaptor 112, an insert 114 and a tool holder 116. Reference numerals for corresponding elements have been shifted by a value of 100.

[0137] The alternative tool assembly 110 is essentially similar to the previously described tool assembly 10, except for three notable differences. The first notable difference is the use of non-centrally located screw(s) 118 (and screw hole(s) 137) to hold the insert adaptor 112 to the tool holder 116. The second notable difference is that the screw holes 137 are not tapered but are simple cylindrical bores. The third is the location of the operational insert 114 relative to the orientation of the bearing surfaces 152.

[0138] Clearly there is also a different insert type and pocket, however, aside from described differences or clearly visible differences such as the insert type, it should be assumed that all the other functional features described above, as well the present notable differences, are applicable to any embodiment of the present invention. The focus on the description below will focus on the notable or visible differences, and undescribed portions can be assumed to correspond to those exemplified above.

[0139] Referring now also to FIGS. 7A and 7B, the insert adaptor 112 can comprise parallel adaptor first and second sides 120A, 120B connected by an adaptor peripheral surface 122, and can have an adaptor index axis I.sub.A extending through the center of the adaptor first and second sides 120A, 120B.

[0140] The adaptor peripheral surface 122 is formed with pockets 124 (also suffixed, e.g., first, second, third, fourth and fifth pockets 124A, 124B, 124C, 124D, 124E). It will be understood that each insert 114 (only one insert being shown, however clearly there can be several simultaneously mounted) and pocket 124 in the present example are identical and hence explanation will be limited to a single example thereof.

[0141] Using the fifth pocket 124E for explanation, it opens out to a front end 126, and can comprise a rear end 128, and opposing upper and lower clamp surfaces 130, 132 extending between the front and rear ends 126, 128.

[0142] A clamping gap 134 can be defined between the upper and lower clamp surfaces 30, 32.

[0143] An ejection gap 136E (also suffixed, e.g., first, second, third, fourth and fifth ejection gaps 136A, 136B, 136C, 136D, 136E) can be defined between the clamping gap 134 and the rear end 128.

[0144] Each ejection gap 136 can be accompanied by a release aperture 137 (also suffixed, e.g., first, second, third, fourth and fifth release apertures 137A, 137B, 137C, 137D, 137E). The fifth release aperture 137E being functionally connected to the fifth pocket 124E and fifth ejection gap 136E thereof.

[0145] As is known in the art, a tool with two projections (not shown) can be inserted into both the fifth ejection gap 136E and the fifth release aperture 137E to eject an insert 114 (not shown in the fifth pocket 124E but rather in the first pocket 124A).

[0146] Notably, as the release aperture 137 does not open out to the adapter peripheral surface 122 it does not weaken the insert adaptor 112 to the extent that an elasticity groove (not shown) would.

[0147] Now referring to the first pocket 124A, it can further be formed with an insert stopper surface 144. The insert stopper surface 144 is located along the periphery of the insert adaptor 112 adjacent the front end 126 and the upper clamp surface 130.

[0148] The insert adaptor 112 can be formed with a fastening configuration 146 which, differing to the previous example, is not in the center thereof. To elaborate, the fastening configuration 146 comprises one or more screw holes which in the present non-limiting example also have the dual function of being the release apertures 137.

[0149] In the present example, in the operational position shown in FIG. 6A, there are three release apertures 137C, 137D, 137E (FIG. 7B) that function as screw holes when the insert 114 shown is. Stated generally, the screw holes furthest from the insert 114 are used to maximize cutting depth obtainable.

[0150] The benefits of using a central fastening configuration 46 are mentioned above, for example, ease of indexability of the insert adaptor 12, less components, less manufacturing related to components, greater ease to produce a smaller adaptor 12. By contrast, the benefits of one or more non-centrally located screw holes (stated differently, circumferentially located screw holes) as exemplified here is that greater cutting depth is possible (the previous example being limited to the center of the adaptor due to the presence of the protruding screw).

[0151] Initially it was believed that the benefits of a single central fastening configuration 46 were superior. However, surprising benefits have also been found for the alternate arrangement. Since the inserts 114 (noting the particular insert shape is not important to this advantage) are easily ejected and replaced multiple times before the pocket 124 wears out, the detriment of completely removing all three screws 118 (e.g. FIG. 6A, also suffixed 118C, 118D, 118E) in order to index the insert adaptor 112, is far less detrimental than for other designs (e.g. a single pentagonal insert with integral multiple edges spaced along the periphery thereof).

[0152] Thus the previously considered modest advantage of a slightly greater cut depth is not as significantly disadvantaged by multiple screws as was initially believed, further increasing the cost effectiveness of such insert adaptors.

[0153] In the present example the screw holes 137 are not tapered, nor are the screw holes 137 offset with the tool holder's tool holes 168 (also suffixed 168C, 168D, 168E). Stated differently, in the present example the screw holes 137 are simple cylindrical bores. Surprisingly, it has been found that even without the tapering and/or offset exemplified in the previous embodiment, which assists in biasing an insert adaptor onto a tool holder, appropriate clamping of the insert adaptor to a tool holder has been achieved. This is by far the simplest design, however certainly the option remains to taper and/or offset the screw holes (as in the previous example) to provide a biasing effect. All three options being feasible for any embodiment of the present invention.

[0154] It is also theoretically possible for an insert adaptor to comprise both screw holes and release apertures, or merely screw holes (depending on the method of insert removal) however, in embodiments where both release apertures and screw holes are used, it is clearly advantageous in terms of structural strength and production to have a combined function.

[0155] The adaptor peripheral surface 122 can be formed with a straight bearing surfaces 152 (also suffixed, e.g. first, second, third, fourth and fifth bearing surfaces 152A, 152B, 152C, 152D, 152E), i.e. in a side view (e.g. FIG. 2B) extending between the pockets 24.

[0156] One of the notable differences mentioned above is the location of the operational insert 114 relative to the orientation of the bearing surfaces 152 (specifically the first bearing surface 152A directly below the insert 114). As will be best understood from FIG. 6A, the first bearing surface 152A extends directly underneath the insert 114. Stated differently the first bearing surface 152A in an operational position is essentially perpendicular to the operational direction D.sub.O. To elaborate, by comparison, in the previous example the bearing surface 52B was essentially parallel with the operational direction D.sub.O, whereas it can be seen that in the present example the corresponding lower bearing surface forms an acute lower surface bearing angle a the operational direction D.sub.O. The angle a is preferably fulfills the condition: 5?<?<25?, more preferably 10?<?<20? and most preferably 13?<?<19?.

[0157] It will be understood that such orientation provides better support underneath an insert. This is achieved by rotating the bearing surfaces 152 relative to the pocket 124 positions (relative to the previous example). This advantageous rotation can also optionally be incorporated for other insert types such as that shown in the previous example. However, for the angled insert type shown in the present figures such orientation is believed necessary.

[0158] A further improvement in the bearing surface 152 is that it can comprise an optional but preferred recessed portion 153 directly adjacent the insert 114. The bearing surface 152 can thus comprise a recessed portion 153, a transition portion 155 and a non-recessed portion 157.

[0159] By not having an entirely straight bearing surface 152, but including a recessed portion 153, any deformation caused by the insert 114 (caused by impacts during machining) more significantly affects the recessed portion 153 rather than the non-recessed portion 157. Thus any deformation or at least less deformation occurs in the non-recessed portion 157 used for abutment with the tool holder 116. Clearly, this feature can be beneficially incorporated into any embodiment.

[0160] Referring to FIGS. 8A to 8C, the tool holder 116 is generally similar, the notable difference being the three tool holes tool holes 168 and the rotated tool bearing surfaces 164A, 164B which are configured to contact the non-recessed portions 157 of each bearing surface 152. The remaining features are generally similar to the previous example.

[0161] The description above includes exemplary embodiments and details for enablement, if needed, of claimed subject matter, and does not exclude non-exemplified embodiments and details from the claim scope of the present application.