MXPA96005334A - Girato drill - Google Patents

Abstract

According to a first aspect of this invention, there is provided a rotating bore including a body which is generally round, has a rotation axis, a front and a rear part, the body comprises an auger, mount mechanisms for mounting that can be released, the bore to an auger to be rotated in a predetermined direction of rotation about the axis of rotation in use, and mechanisms for mounting peaks including an anvil formation defining an anvil surface extending forward and an opposing retention formation defining a retaining surface extending forward, the anvil surface and the retaining surface diverging forwardly to form therebetween a correspondingly forwardly extending slot, the slot of which tapers backward at an angle less than about 5ø, and a peak of abrasion resistant hard material that has front and rear tails tapering back in an angle that is complementary to the slot angle, where the spout is operatively received in the slot such that the peak pressure during drilling, in a longitudinal direction opposite to that of the direction in which the drill advances, wedges the peak in the slot to cause a frictional retention of the peak in the slot, where the anvil surface, relative to the predetermined direction of rotation in use, is arranged to drag the pick, the anvil surface having a non-planar seat for seating the spout having a complementary seat formation, the anvil surface extending forward to a position of a very small distance from the front end of the spout to support the spike along of a large length portion, finishing the retention formation longitudinally near the front end of the yun surface that and very close to the front end of the beak to leave a relatively long portion of the bill to its exposed forehead. The taper angle can be between 1 ° and 3 ° approximately, preferably 2 ° approximately. In a preferred embodiment, said beak mount mechanism may first be a beak mount mechanism generally disposed radially to one side of the axis of rotation and in which said beak may be a first peak, the drill including a second mechanism of peak mount spaced circumferentially from the first peak mount mechanism and a second peak received in a similar manner in the second peak mount mechanism. The drill can be symmetrical around the axis of rotation. The first and second peak mount mechanism may be identical and the first and second peaks may be identical. The first and second peaks can be aligned radially. In one embodiment, the peaks may have cusps or front limbs towards their radially internal ends. If desired, the first and second peaks may be integrated to form a composite peak. This incorporation can be particularly useful in the application known as "dry drilling", that is, when drilling is performed without water as a lubricant or washed medium. In another embodiment, the first peak may have a cusp or a forward limb toward a radially internal end and the second peak may have a front cusp or limb toward the radially outer end. In one embodiment, an opening can be provided through the body, the opening of which is transverse to the slot and is open to the rear or the bottom of the slot in such a way as to allow a thin end of a tapered mandrel to be inserted below the slot. a rear end of the spout and that pulls the peak of the slot by progressive penetration of the tapered mandrel in the opening. In this way, the spout can be released from the body by light strokes or by tapering a mandrel into the opening. According to a second aspect of this invention, a rotating drill is provided including a body that is generally round having a rotational axis, a front part and a rear part, where the body comprises a bit mount mechanism for mounting, so that it can be released, the drill in an auger to be rotated in a predetermined rotation direction about the axis of rotation in use, and a mechanism for mounting peaks including an anvil formation defining an anvil surface extending forward and an opposing retention formulation defining a a forwardly extending retaining surface, wherein the anvil surface and the retaining surface diverge forward to form therebetween a correspondingly forwardly extending slot, the slot of which tapers rearward at an angle less than about 5øand a peak of abrasion resistant hard material having front and rear sides tapering back from an angle that is complementary to the slot angle, where the peak is operatively received in the slot such that the pressure in the peak during drilling, in a longitudinal direction opposite to that in the direction in which the drill advances, wedges the beak into the slot to cause a retention by friction of the groove beak, where the anvil surface, relative to the predetermined rotation direction in use, it is arranged to drag the spout, the anvil surface and the retaining surface having a non-planar seat to seat the spout having a complementary seat formation, in which the anvil formation has a section relatively thick cross section and is correspondingly relatively stiff and the retention formation has a relatively thin cross section and it is correspondingly relatively elastic. According to a third aspect of this invention, a rotating bore is provided including a body that is generally round having an axis of rotation, a front part and a rear part, where the body comprises a mounting mechanism of auger for mounting, so that it can be released, the bore in an auger to be rotated in a predetermined rotation direction about the axis of rotation in use, and a mechanism for mounting peaks including an anvil formation defining an anvil surface extending forward and an opposed retaining formation defining a forwardly extending retaining surface, wherein the anvil surface and the retaining surface diverge forward to form a correspondingly forwardly extending slot therebetween, the slot of which tapers. backward at an angle less than about 5ø, and a peak of abrasion resistant hard material that has ne front and rear sides tapering backward in an angle that is complementary to the slot angle, where the peak is operatively received in the slot such that the pressure at the peak during drilling, in a longitudinal direction opposite to the of the direction in which the drill advances, wedges the pick in the groove to cause a frictional retention of the pick in the groove, where the anvil surface, relative to the predetermined direction of rotation in use, is arranged to drag the pick the anvil surface having a non-planar seat for seating the peak having a complementary seating formation, the anvil surface extends forward substantially towards the front end of the peak substantially completely to support the peak, where the formation of retention ends longitudinally near the front end of the beak to leave a portion of the beak exposed towards its e front, the retention formation, in relation to anvil formation, is of a thinner and more elastic cross section, a method is provided to release the body peak, including the method of applying heat to the retention formation to cause the retention formation to deform to open the slot. Consequently, and with advantages, the peak can be released to allow replacement in itself.

Description

"ROTARY DRILL" BACKGROUND OF THE INVENTION This invention relates to a rotating drill of the type comprising a body having mounting mechanisms for mounting on an auger, and carrying one or more cutting peaks of a hard and abrasion resistant material, whose peaks are Ordered to cut rock or rock-like substrate in its use. It also relates to a method for releasing such a peak from said body. The Applicant believes that this invention will find application particularly in the field of drills for use in coal mining operations. For purposes of this specification, that application will remain predominantly in mind, but the invention is not limited to that application. In coal mining, a coal seam is extracted by a row of holes continuing to leave an empty space between a hanging stone and a standing stone. To prevent the collapsing plinth from collapsing, deep holes are drilled in the hanging plinth and roof bolts are anchored in the holes to allow the support structure to be suspended from the roof bolts. The Applicant believes that a drill according to this invention can be used with advantages in the drilling of such deep holes. BRIEF DESCRIPTION OF THE DRAWINGS The invention has been described by way of examples with reference to drawings of accompanying diagrams. In the drawings of Figure 1, a first embodiment of a rotary hole and a peak according to this invention is shown in a three-dimensional side view - Figures 2 and 3 show the peak of Figure 1 respectively in a view of the end according to arrow II, and a plan view according to the arrow III; Figure 4 shows a view corresponding to Figure 1, but with the peak seated inside the body of the drill; Figure 5 shows, in a view corresponding to Figure 1, a second embodiment of a rotating drill according to this invention; Figures 6, 7 and 8 show, respectively, in three-dimensional side view, in a flat view and in a flat view, three additional additions of peaks forming part of rotating bores according to the invention; and Figure 9 shows, in a side view, a further embodiment of a rotating drill according to this invention. DETAILED DESCRIPTION With reference to Figures 1 to 4 of the drawings, a rotary drill of the type described is generally indicated with the reference number 10. It has a handle 12 having an auger mount mechanism which may be conventional in a free rear part and there mount the body 10 in an auger. The body 10 generally has a round shape about an axis of rotation or longitudinal 14. The body 10 is symmetrical about the axis 14 having a pair of diametrically opposed peak mounting mechanisms in its front part. The beak mount mechanisms are identical and only one is described in detail. The bead mount mechanism includes an anvil formation 16 having an anvil surface 18 that extends forward and looks in a direction in which rotation will take place in use to perform the drilling. The anvil surface 18 is composed in that it generally has a concave shape, more specifically in the form of an obtuse dihedron such that a longitudinal line 18.3 divides the two surfaces 18.1 and 18.2. Advantageously, the formation of yun-16 is pointed at a free end as shown at 19. Circumferentially spaced from the anvil formation, an opposite retention formation 20 having a retaining surface is provided (part dark in the drawing) facing the anvil surface 18 such that a longitudinally extending slot 22 is provided and is intermediate between the anvil surface 18 and the retaining surface. The retaining surface lies advantageously in a radius (N. of the T. radius is equivalent to the length of the segment joining the center with the circumference of a circle). The slot 22 is tapered as will be described of the body 10 from this moment. The anvil formation 16 is sturdy or rigid and has a relatively thick cross section and the retention formation is relatively elastic and has a relatively thin cross section. A tip or spout 30 is in the process of being received into the slot 22. The spout 30 has a back piece 32 and an operative face layer 34., of a hard and abrasion resistant material. In a preferred sophisticated embodiment, the face layer 34 is made of a polycrystalline diamond material. The face layer 34 is flat and lies against a flat face of the rear part 32. An opposite surface of the rear part 32 has a dihedral shape, is complementary to the shape of the anvil surface 18. Along an upper edge from the rear part 32, the pointed shape 19 of the anvil formation 16 extends, as shown in 36. The slot 22 is formed to converge or taper at a narrow angle in one direction from an open front end in the direction of back or towards the bottom. The spout 30 is tapered in a corresponding manner to fit without slack in the groove 22. In the embodiment shown, the angles are equal in about 21. In use, as the drilling operations begin, the spout 30 will be driven deeper into its seat so that it is frictionally located and secured in a spindle or wedge within its seat. The dihedral shape of the anvil surface 18 and the complementary shape of the rear part 32 locate the spout 30 within the slot 20. In use, the rotation occurs in a direction such that the spout 30, and more specifically its face operative 24 advances. Accordingly, the spout 30 receives support by forming anvil 16. It is important that the anvil formation 16 extends relatively far forward to remain only a small distance from the front of the spout 30 in order to thereby support the peak toward a position near your limb in use. For rotating drills that are suitable for drilling holes between 20 mm in diameter and 40 mm in diameter, the end of the anvil formation may be slightly separated from the tip of the beak by between 2 mm and 10 mm, preferably between 3 mm and 6 mm, and more preferably between 4mm and 5 mm. It is also important that the retention formation extends only toward a fairly short forward position of the front of the spout 30, thus leaving a large portion of, in fact, most of the working layer 34 exposed. This ensures that a large work area to be cut into the substrate is available which leads to a high degree of penetration or drilling in use. Additionally, it extends the useful life of the peak. This feature becomes apparent in Figure 4. When the peak 30 is to be released from the body 10, the anvil formation 16 and the retaining formation 20 are heated, more specifically in the vicinity of the anvil surface 18 and on the surface retention. The thermal expansion concentrated along the surface of the anvil 18 and the retaining surface causes the slot 22 to open slightly and therefore expand the angle of convergence to release the peak 30.

Instead, if desired, a transverse opening 37 is provided through the body in an exposed, predetermined relationship with the bottom of the slot 22 to allow a thin end of a tapered mandrel 38 to be inserted below the spout. By lightly tapping the tapered mandrel 38 towards the opening, frictional belaying of the beak is broken by a wedging action to release the beak. A first advantage of the invention, especially with respect to the peaks that have the tendency to wear while the body 10 is still useful, is that those peaks can easily be replaced with new peaks in situ. More specifically, in the preferred embodiment, the only infrastructure required to replace this peak is a heat source which can be applied in a relatively concentrated manner. The Applicant considers an important advantage of the invention to be that related to highly sophisticated modern peaks, especially peaks of polycrystalline diamantle material. Those peaks can last a long time, and can last longer than the bodies that carry them. Consequently, in those cases, it is desirable to have the ability to release a peak from the body when the body has worn out and be able to mount it in a new body. With respect to this, it should be appreciated that although the peak is so efficient to cut that it is effective in economic terms, it is in fact very expensive and therefore it is very important to allow it to function optimally. Accordingly, the invention allows these pipelines for such sophisticated and expensive drills according to this invention to be replaced in new bodies in situ. With respect to this, it should be appreciated that the conventional practice of removing the drills from the mine to be rearmed and then transported back to the mine, requires a substantial transportation capacity. This practice can now be improved by using rotary drills according to this invention. The Applicant also considers an important advantage that the peaks can be assembled and released in and from the bore bodies in a user-friendly manner, which is also an advantage in terms of time and cost. A further advantage is that the mounting mechanism in the body can be produced by precision casting, obviating expensive disassembly operations of narrow tolerance material. In this regard, it is extremely important to appreciate that the mechanism of locking or securing of spindle or wedging allows the beak to find its own longitudinal position in the groove, thus obviating narrow manufacturing tolerances - for example, with respect to the width of the slot. The applicant considers an advantage that the pick receives support along a large portion of its length towards an advantageous position at a very short distance near its front end, in a rigid form by the shape of a rigid anvil, although some elasticity or "elasticity" is provided by the relatively elastic retaining member. Rigid support is expected to improve peak force requirements, which is a costly component. The elasticity is expected to improve manufacturing tolerances and increase the frictional retention of the groove peak. With reference to Figure 5 of the drawings, a further embodiment of a rotating drill according to the invention is shown, having components and characteristics that are very similar to those of the embodiment of Figure 1. Similar numbers are used to denote similar characteristics and the incorporation is not described again in detail. The differences between the additions of Figures 1 and 5 will simply be indicated. The peaks 130 of the embodiment of Figure 5 have tips or cusps towards their radially internal ends as indicated in 136 which projects farthest. Correspondingly, the anvil formations 116 are also projected to the greatest distance at their radially internal ends as indicated by the reference number 119. The longitudinal inner edges of the peaks are closely adjacent to one another, but do not touch each other. The purpose of not transmitting forces due to tension and deformation between them in use. Conversely, each retention formation 120 is chamfered at a surface angle at its radially internal end as indicated by the reference number 121. This further enlarges the portion of the work surface 134 of each peak 130 that is exposed in use. Advantageously, a rear end of the peak is chamfered as shown at 135 at an angle 135, for example, approximately 5o. This facilitates the entry of the peak into the slot 122 and prevents it from "penetrating" when it is pushed into the slot. The peaks 130 are in the form of carbide insert pieces, ie, they do not have the polycrystalline diamond layer of the peaks 30 of Figure 1. With reference to Figure 6, yet another embodiment of a peak indicated generally by the reference number 230. This is similar to the peak 130 of Figure 5 except that a rear face 232 is formed in three planes as opposed to the two planes of the incorporation of Figure 1 and Figure 5. Therefore , between the external planes 232.1 and 232.2, there is also a central plane 232.3 The applicant believes that this configuration will improve the settlement and therefore the placement of the peak in the seat provided by the anvil surface. One skilled in the art can easily see that the face of the anvil piece can be formed in a complementary manner to shape the rear part 232 of the spout 230. Instead, if desired, the face of the anvil part. it may be similar to the faces 18 and 118 of the anvil pieces 16 and 116 respectively of Figures 1 and 5. In such embodiment, the flattened portion 232.3 will simply be held slightly proud of the viewing line 18.3, 118.3 of the faces 18, 118. This will improve manufacturing tolerances and even accommodate foreign matter that may have accumulated in the vicinity of the dividing line 18.3, 118.3. With reference to Figure 7, even another embodiment of a peak is indicated by the reference number 330. Its rear part 232 has a flat central portion 332.3 similar to that of the flat portion 232.3 of the embodiment of Figure 6. However , the flat central portion 323.3 is flanked by the concave surfaces 332.1 and 332.2. A face of a complementary anvil formation will be formed in complementarity, which can be easily visualized by an expert in this field. It is expected that the spout 330 will settle particularly without slack and therefore will be placed particularly well in its anvil formation in use. Yet another embodiment of a peak is generally indicated by reference number 430 in Figure 8. This also has a flat central portion 432.3 generally parallel to the work surface 434. However, it is flanked on either of its sides by generally convex boundaries which, in this embodiment, are angular in two steps each, that is, they have chamfered portions 432.1 and 432.2 close to the flat central portion 432.3 and then are chamfered along sharper angles to run towards outside on the work surface 434. With reference to Figure 9 there is indicated a further incorporation of a rotating drill according to the invention generally by a reference number 500. The drill 500 comprises a body generally indicated by a reference number. 510 and two peaks of hard and abrasion resistant material indicated respectively by reference numerals 530.1 and 530.2. The components and features of the embodiment of Figure 9 are generally similar to the feature components of the embodiments already described. Similar reference numbers are used to indicate similar features and components that are not described again in detail. Emphasis is simply placed on a unique feature, which differentiates the incorporation of Figure 9 of the incorporations already described. Peak 530.1 has a front peak or limb as indicated by reference numeral 536.1 to a radially outer end. Accordingly, the peak or limb 536.1 in use directs the cutting action in the radially outer regions of a hole being drilled. Against distinction, peak 530.2 has a front peak or tip 536.2 towards a radially internal end. Accordingly, the peak or limb 536.2 will direct the cutting action in the radially internal regions of the hole being drilled in use. The tips of the extremities 536.1 and 536.2 are generally in the same longitudinal position. The applicant considers as an advantage of the incorporation of Figure 9 the fact that he will act as a "heart cutter". Consequently, the cut does not take place at the same depth throughout the entire ex tension of the hole being drilled, but instead is concentrated along, respectively, a radially external cutting circle and, respectively, a radially internal cutting circle thus improving the required torsional moment of drilling and consequently also the tension in the peak and the body formations that support the peaks. It should be appreciated, with respect to all the embodiments of Figures 5 onwards, that the grooves in the bodies taper backwards at a small angle, that the peaks taper backwards in complementarity and that the reception of the peaks in the grooves in each case is in a friction assurance manner with wedging as described in detail with reference to the embodiment of Figure 1. The embodiments of Figures 5 onwards generally have the same advantages described in greater detail with reference to the incorporation of the Figure 1.

Claims (11)

1. NOVELTY OF THE INVENTION Having described the invention, it is considered as a novelty and therefore the one included in the following CLAUSES is claimed; 1. A rotating drill including: a body which is generally round, has a rotation axis, a front and a rear part, - the body comprises an auger, mount mechanisms to be mounted in a releasable manner, the drill an auger to be rotated in a predetermined rotation direction about the axis of rotation in use, and mechanisms for mounting peaks including an anvil formation defining an anvil surface extending forward and an opposing retention formation defining an a retaining surface extending forward, the anvil surface and the retaining surface being positioned diverging forwardly to form a correspondingly forwardly extending slot therebetween, the slot of which tapers rearward at a smaller angle at about 5o; and a peak of abrasion resistant hard material having front and rear sides tapering backward at an angle that is complementary to that of the slot angle, where the peak is operatively received in the slot such that the pressure at the peak during drilling, in a longitudinal direction opposite to that in the direction in which the drill advances, wedges the beak into the groove to cause a frictional retention of the beak in the groove, where the anvil surface, relative to the predetermined direction of rotation in use, it is arranged to drag the spout, the anvil surface having a non-planar seat to seat the spout having a complementary seat formation, the anvil surface extending forward to a position of a distance Very small of the front end of the beak to support the beak along a large portion of its length, ending the long retention formation it is close to the front end of the anvil surface and very close to the front end of the beak to leave a relatively long portion of the beak to its exposed forehead.
2. 2. A rotary drill as set forth in clause 1 in which said beak mount mechanism is first beak mount mechanism generally disposed radially to one side of the axis of rotation and in which said peak is a first peak, the drill including a second mount mechanism of the peak spaced circumferentially from the first peak mount mechanism, and a second peak received simul- taneously in the second mount mechanism of the peak.
3. 3. A rotary drill as set out in clause 2 in which the first and second peaks are aligned radially.
4. 4. A rotary drill as set out in clause 2 which is symmetrically about the axis of rotation.
5. 5. A rotary drill as set forth in clause 4 in which the first and second peak mount mechanisms are identical and in which the first and second peaks are identical.
6. 6. A rotary drill as set out in clause 2 in which the peaks have points or cusps or front limbs towards their radially internal ends.
7. 7. A rotary drill as set forth in clause 2 in which the first peak has a cusp or tip or front end towards a radially internal end and the second peak has a cusp or tip or forward end towards a radially outer end .
8. 8. A rotary drill as set forth in clause 3 in which the first and second peaks are integrated and form a compound peak.
9. 9. A rotary drill as set out in clause 1 which has an opening through the body whose opening is transverse to the groove and opens backwards or towards the bottom of the groove in such a way as to allow the thin end of a tapered mandrel is inserted below a rear end of the spike and pulls the spike out of the slot by a progressive penetration of the tapered mandrel into the aperture.
10. 10. A rotary drill that includes: a body that is generally round that has a rotation axis, a front part and a rear part, wherein the body comprises a barrel mount mechanism for mounting, so that it can be released, the drill in an auger that will be rotated in a predetermined direction of rotation about the axis of rotation in use , and a mechanism for mounting peaks including an anvil formation defining an anvil surface extending forward and an opposing retention formation defining a retention surface extending forward, where the anvil surface and the surface of the anvil The detent diverges forward to form a correspondingly forwardly extending slot therebetween, the slot of which tapers rearward at an angle less than about 5o, and a peak of abrasion resistant hard material having front sides. and rear that taper backward at an angle that is complementary to that of the slot angle, where the peak is operatively received e in the groove such that the pressure at the peak during drilling, in a longitudinal direction opposite to that in the direction in which the drill advances, wedges the beak into the groove to cause a frictional retention of the beak in the slot, wherein the anvil surface, relative to the predetermined direction of rotation in use, is arranged to entrain the peak, the anvil surface and the retaining surface having a non-planar seat to seat the peak having a full seat formation. -nement, in which the anvil formation has a relatively thick cross section and is correspondingly relatively stiff and the retention formation has a relatively thin cross section and is correspondingly relatively elastic.
11. 11. A rotating drill including: a body that is generally round having a rotation axis, a front part and a rear part, where the body comprises a bit mechanism mounting mechanism, so that it can be released, the drill in an auger that will be rotated in a predetermined rotation direction about the axis of rotation in use, and a mechanism for mounting peaks including an anvil formation defining an anvil surface that extends forward and an opposing retention formation that de-fine a retaining surface that extends forward, where the anvil surface and the retaining surface diverge forward to form between them a slot that extends correspondingly forward, whose slot tapers backwards in an angle less than about 5o; and a peak of abrasion resistant hard material having front and rear sides tapering backward at an angle that is complementary to that of the slot angle, where the peak is operatively received in the slot such that the pressure in the peak during drilling, in a longitudinal direction opposite to that in the direction in which the drill advances, wedges the beak into the groove to cause a frictional retention of the beak in the groove, where the anvil surface, relative to the predetermined rotation direction in use, it is arranged to drag the spout, and the retention surface is positioned to direct the spout, and where one of the anvil surfaces and retaining surface has a non-planar seat to seat the spike that has a complementary seating formation, including the method of applying heat to the retention formation to cause the retention formation to deform to open to slot. SUMMARY OF THE INVENTION According to a first aspect of this invention, there is provided a rotary bore including a body which is generally round, has a rotation axis, a front and a rear part, - the body comprises an auger, mechanisms of mount for releasably mounting the drill to an auger to be rotated in a predetermined direction of rotation about the axis of rotation in use, and mechanisms for mounting peaks including an anvil formation defining an anvil surface which extends forward and an opposing retention formation defining a retaining surface extending forward, the anvil surface and the retaining surface being positioned diverging forwardly to form a slot extending therebetween. correspondingly forward, the slot of which tapers rearward at an angle less than about 5o; and a peak of abrasion resistant hard material having front and rear sides tapering backward at an angle that is complementary to that of the slot angle, where the peak is operatively received in the slot such that the pressure in the peak during drilling, in a longitudinal direction opposite to that in the direction in which the drill advances, wedges the beak into the groove to cause a frictional retention of the beak in the groove, where the anvil surface, relative to the predetermined rotation direction in use, it is arranged to drag the spout, the anvil surface having a non-planar seat to seat the spout having a complementary seat formation, the anvil surface extending forward towards a position of a very small distance of the front end of the beak to support the beak along a large portion of its length, ending the formation of retaining longi tudinally near the front end of the anvil surface and very close to the front end of the beak to leave a relatively long portion of the beak to its exposed forehead. The taper angle may be between Io and approximately 3 °, preferably approximately 2 °. In a preferred embodiment, said beak mount mechanism may first be a beak mount mechanism generally disposed radially to one side of the axis of rotation and in which said beak may be a first peak, the drill including a second mechanism of peak mount circumferentially spaced from the first peak mount mechanism and a second peak similarly received in the second peak mount mechanism. The drill can be symmetrical around the axis of rotation. The first and second beak mount mechanisms may be identical and the first and second beaks may be identical. The first and second peaks can be aligned radially. In one embodiment, the peaks may have front cusps or extremities towards their radially internal ends. If desired, the first and second peaks may be integrated to form a composite peak. This incorporation can be particularly useful in the application known as "dry drilling", that is, when drilling is performed without water as a lubricant or washing medium. In another embodiment, the first peak may have a cusp or a forward limb toward a radially internal end and the second peak may have a front cusp or limb toward the radially outer end. In one embodiment, an opening can be provided through the body, the opening of which is transverse to the groove and is open to the rear or bottom of the groove in such a way as to allow a thin end of a tapered mandrel to be inserted. below a rear end of the spout and that pulls out the spout from the slot by progressive penetration of the tapered mandrel into the opening. In this way, the spout can be released from the body by light blows or by tapering a mandrel into the opening. According to a second aspect of this invention, a rotary bore is provided including a body that is generally round having a bearing axis, a front part and a rear part, where the body comprises a bit frame mechanism for mounting, so that it can be released, the bore in an auger that will be rotated in a predetermined direction of rotation about the axis of rotation in use, and a mechanism for mounting peaks including an anvil formation defining an anvil surface extending forward and an opposing retention formation defining a forwardly extending retaining surface, wherein the anvil surface and the retaining surface diverge forward to form a correspondingly forwardly extending slot therebetween. whose groove tapers back at an angle less than about 5o; and a peak of abrasion-resistant hard material having front and rear sides tapering backward at an angle that is complementary to that of the slot angle, where the peak is operatively received in the slot such that pressure in the peak during drilling, in a longitudinal direction opposite to that in the direction in which the drill advances, wedges the beak into the groove to cause a frictional retention of the beak in the groove, where the anvil surface, relative to the predetermined rotation direction in use, it is arranged to drag the spout, the anvil surface and the retaining surface having a non-planar seat for seating the spout having a complementary seating formation, in which the anvil formation has a relatively thick cross section and is correspondingly relatively stiff and the retaining formation has a relatively thin cross section and it is correspondingly relatively elastic. According to a third aspect of this invention, a rotating bore is provided including a body that is generally round having a rotation axis, a front part and a rear part, where the body comprises an auger mount mechanism for mounting, so that it can be released, the bore in an auger that will be rotated in a predetermined rotation direction about the axis of rotation in use, and a mechanism for mounting peaks including an anvil formation defining an anvil surface that is extends forward and an opposing retention formation defining a forwardly extending retaining surface, wherein the anvil surface and the retaining surface diverge forward to form a correspondingly forwardly extending slot therebetween. ra-nura tapers back at an angle less than about 5o; and a peak of abrasion resistant hard material having front and rear sides tapering backward at an angle that is complementary to that of the slot angle, where the peak is operatively received in the slot such that the pressure in the peak during drilling, in a longitudinal direction opposite to that in the direction in which the drill advances, wedges the beak into the groove to cause a frictional retention of the beak in the groove, where the anvil surface, relative to the predetermined direction of rotation in use, it is arranged to drag the spout, the anvil surface having a non-planar seat to seat the spout having a complementary seat formation, the yun-surface extending forward substantially towards the front end of the peak substantially completely to support the peak, where the retention formation ends longitudinally near the front end of the peak to leave a portion of the peak exposed towards its front part, the retention formation, in relation to the anvil formation, is of a thinner and more elastic cross section; A method for releasing the body peak is provided, the method including applying heat to the retention formation to cause the retention formation to deform to open the groove. Consequently, and with advantages, the peak can be released to allow replacement in situ.