WO2004035264A1

WO2004035264A1 - A discrete angle adjustment mechanism for a tang

Info

Publication number: WO2004035264A1
Application number: PCT/IL2002/000834
Authority: WO
Inventors: Eliyahu Benita
Original assignee: Efd Diamond Manufacturers And Exporters Ltd.
Priority date: 2002-10-17
Filing date: 2002-10-17
Publication date: 2004-04-29
Also published as: AU2002334373A1

Abstract

A tang (7) enabling simple, consistent and accurate adjustment and readjustment of the angle of a diamond during the polishing and faceting process thereof. The tang (7) comprises an elongated body (14) to which is attached a discrete angle adjustable device (30) (70) adapted for holding a diamond dop. The discrete angle adjustable device (30) (70) comprises two orthogonally arranged rotatable mechanisms, each of which is formed with a pattern of radially extending grooves (42) on an outer face, for insertion therein of an engagement device (58). Upon rotation of each rotatable mechanism, insertion of the appropriate engagement device within the grooves (42) is accompanied by an audible click. The precise angular adjustment of the device may therefore be calculated by counting the number of clicks, where the precise angular difference between adjacent grooves is known. The discrete angular adjustment device (30) (70) may be used in conjunction with a continuous angle adjustment device (96) to enable continuous angular adjustment of the dop.

Description

A DISCRETE ANGLE ADJUSTMENT MECHANISM FOR A TANG

Field of the Invention

The present invention relates to devices for holding diamonds during the polishing and faceting process, and more particularly to a tang enabling adjustment of the angle and position of a dop holding a diamond to achieve highly accurate polishing of the diamond.

Background of the Invention

Diamonds are generally polished by hand, substantially in the manner in which they have been polished for centuries. Polishing is achieved by means of gently applying the diamonds against a rotating polishing wheel at various angles. The angles at which the diamond comes into contact with the polishing wheel are dependent upon the type of diamond being polished.

Due to the delicacy and the accuracy involved in the polishing of diamonds, the polishing process requires the use of a steady and firm structure to hold the diamond in a desired position while applying it to the polishing wheel. Two structures that operate in conjunction are currently in use for the purpose of holding the diamond during the polishing process. These structures are commonly referred to as a tang and a dop.

A dop is essentially a structure designed to hold a diamond in place during application against a rotating polishing wheel. The dop must be capable of angular adjustment to enable the diamond which it holds to be applied to the polishing wheel at various angles.

A tang is a structure designed to hold the dop and provide it with a stable, stationary platform. The dop is connected to the tang by a device which enables slanting of the dop in relation to the tang.

Different types of tangs and dops, used for different purposes, are widely known in the art. The combination of the dop and the tang provide a high degree of control over the diamond during the polishing process.

Different tangs and dops are used for the polishing of diamonds of different sizes. Moreover, even while working on the same diamond, different tangs and dops are used for the purpose of polishing different portions of the same diamond. There are two main phases in the polishing of a diamond. The first is polishing the general shape of the diamond and the forming of large facets. The second stage is the decoration of each side of the polished diamond with smaller facets each in a different angle. In order to achieve these facets, the ability to perform changes of the angle in which the diamond comes into contact with the polishing wheel is required. These changes are currently performed manually, by either changing the angle of the dop itself, or, in more advanced tangs, by use of an adjustment tool situated on the tang, mediating between the tang's arm and the dop. In both cases, the changes made are performed manually by the shaper, according to his estimate of the correct angles to be used.

Accordingly, currently known tangs can be divided into two groups. The first group consists of tangs that have a very simple mechanism for performing angle adjustments e.g. simple horizontal and vertical hinges to which the dop is attached which enable vertical and horizontal slanting of the dop by applying human force to the hinges in the desired direction. Such a tang is shown in Fig. 1. The second group consists of tangs that use very complex angle adjustment mechanisms that allow for very slight angle adjustments of the dop e.g. by means of rotations of a screw that activates some sort of an angle adjustment mechanism that enables very slight angle adjustments.

Whichever the type of tang or the angle adjustment means used, still, in either case, the degree of slanting required for each facet is determined by the polisher shaping the diamond, according to his estimate.

Therefore, polishing a diamond with known tangs using currently known angle adjustment mechanisms requires a very skilled and experienced user in order to achieve the highly accurate angles desired, and in order to be able to replicate the desired angles from facet to facet (to achieve symmetry of a diamond) and from diamond to diamond (to polish similarly shaped diamonds). This is the case both when the aforementioned complex angle adjustment mechanisms are used and when the simple angle adjustment mechanisms are used, since in both cases, as aforementioned, the angle at which the diamond is brought into contact with the polishing wheel is set according to an estimate made by the polisher, without using an accurate measurement means. This is particularly true for the faceting phase, because the whole adjusting method is dependent on the sensitivity of the polisher's hands, upon the ability of the polisher to estimate the correct angle for the formation of each facet, and upon the polisher's ability to readjust previously determined angles accurately when forming symmetric facets on other parts of a diamond.

Furthermore, even a skilled and experienced polisher has no protection against error, since his work quality may be adversely affected by various factors, such as the stone size (i.e. when the diamond is less then 30 pt.) and fatigue induced after polishing numerous diamonds. It should be mentioned that tangs are known which include an angle measurement device, but these devices are very crude and complicated, and involve combining angle rulers into the structure of the tang or the dop, etc.

Therefore, it would be desirable to provide a tang which may be easily adjusted and readjusted during the polishing process to enable achievement of consistent, highly accurate facet angles.

Sirmmary of the Invention

Accordingly, it is an object of the present invention to overcome the disadvantages of the prior art and provide a tang enabling simple, consistent and accurate adjustment and readjustment of the angle of a diamond during the polishing and faceting process. According to a preferred embodiment, the arm of the tang has connected therewith an adjustable apparatus, which comprises two adjusting tools, one for vertical adjustment and the other for horizontal adjustments. The adjusting tools are interconnected and each of them comprises a disc and pivot. Each disc has inherent grooves along the radial direction from the center of the disc, each groove corresponding to a different angle. As a knob is inserted into these grooves, a click can be heard. Hence the diamond can be adjusted to the desired angle by counting the number of clicks heard during the adjustment process. Moreover, because of the presence of the knob, the disc is retained in position, thus the diamond position is held steady for the purpose of polishing. In accordance with a preferred embodiment of the present invention, there is provided a tang for holding a dop during polishing and faceting of small diamonds, the tang arm comprising a unitary elongated body and a discrete angle adjustable device fixedly attached to said elongated body, for enabling discrete angular adjustment of the dop, wherein the dop is connected to the discrete angle adjustment device.

A feature of the present invention is that the tang arm can be simply and accurately adjusted to a desired angular orientation by counting of audible clicks emitted during the adjustment process.

An advantage of the present invention is that minimal skill is required to achieve accurate alignment and realignment of a dop connected with a tang arm.

Brief Description of the Drawings

For a better understanding of the invention with regard to the embodiments thereof, reference is made to the accompanying drawings, in which like numerals designate corresponding sections or elements throughout, and in which:

Fig. 1 shows a tang and a dop in accordance with the prior art; Fig. 2 shows a preferred embodiment of the tang of the present invention in conjunction with a base and dop;

Fig. 3 shows an exploded view of the tang arm and of the angle adjustment mechanism of the present invention;

Fig. 4 shows an alternative embodiment of the tang arm of the present invention; Fig. 5 shows an alternative embodiment of the tang arm of the present invention further comprising a continuous angle adjustment device;

Fig. 6 shows an exploded view of the additional angle adjustment device of Fig. 5; and

Fig. 7 shows the tang arm of Fig. 5 in conjunction with a base and a dop.

Detailed Description Fig. 1 shows a prior art tang 10 and standard dop 12 having a simple hinge mechanism 13 for manual adjustment of the angle of dop 12 in relation to tang 10. Fig. 2 shows a preferred embodiment of the tang 7 of the present invention, for holding a standard dop 12 which retains a diamond (not shown) during the polishing and faceting process, and enables simple and accurate adjustment and readjustment of the angle and position of the diamond. The tang 7 comprises base 9 and tang arm 14. Towards the end of tang arm 14 there is implemented the angle adjustment mechanism 11 of the present invention. The structure and operation of tang arm 14 and of angle adjustment mechanism 11 can be better explained with reference to Fig. 3.

Fig. 3 shows an exploded view of the tang arm 14 and of the angle adjustment mechanism 11 of the present invention.

Tang arm 14 comprises an elongated member 15 in which rear end 16 is shaped for retention within base 9 (shown in Fig. 2) and front end 18 is shaped for retaining angle adjustment mechanism 11, which in turn retains the dop 12 (shown in Fig. 2). Rear end 16 comprises a substantially flat horizontal surface 20 and narrow vertical sides 22 extending downwards from surface 20. Surface 20 is provided with a sequence of holes 24 into which are inserted screws 25 (shown in Fig. 2) to fasten surface 20 to base 9.

Rear section 16 extends into forked front section 18, comprising two vertical sides 26 and 26a. Each side 26 and 26a is provided with a first through-hole 27 towards its front edge. A second through-hole 28, inwardly displaced from first through-hole 27, is provided on side 26a.

An elongated U-shaped recess 29 is formed in the forward-most portion of horizontal section 20, for positioning therein of a first adjustment device 30. Discrete adjustment device 30 provides adjustment in a vertical plane. Discrete adjustment device 30 comprises a semi-circular disc arrangement 32 combined with two perpendicular flat faces 34 and 36, and provided with a central through-hole 38.

On one face 40 of semi-circular disc arrangement 32, which is positioned facing side section 26a, a pattern of discrete grooves 42 is formed, extending radially inwards from the circumference of face 40.

Vertical face 34 of adjustment device 30 is provided with an inwardly- extending channel 45 at its upper section. A spring 43 is situated within channel 45 and a ball-bearing 44 is situated at the opening to channel 45. An elongated protrusion 46 having a threaded end 48 is centrally positioned on vertical face 34. Adjustment device 30 is positioned within recess 29 such that grooves 42 are facing towards side 26a, and vertical face 34 is forward facing, and with central through-hole 38 aligned with through-holes 27 of vertical sides 26 and 26a of tang arm 14. A screw 50 is inserted into through-holes 27 and 38, such that threaded end with a nut 52 positioned on threaded edge 54 of screw 50. Nut 52 is fastened tightly such that adjustment device 30 is unable to rotate freely about its axis. A pair of O- rings 56 are positioned at opposite ends of screw 50.

A spring-loaded, ball-bearing engagement device 58, is screwed into through- hole 28. Device 58 comprises a nut 60, a hollow threaded member 62 having an open end 63 and a second end fixedly retained within nut 60 , a spring 64 positioned within member 62, and a ball-bearing 65 situated at end 63. Through holes 27 and 28 are positioned relative to one another such that when adjustment device 30 and engagement device 58 are fixed in position, ball bearing 65 is engaged within grooves 42 of adjustment device 30, preventing free rotation of adjustment device 30.

In order to adjust the angle of adjustment device 30, elongated member 15, when connected with base 9, is grasped in one hand and adjustment device 30 in the other. A sufficient amount of force is exerted on device 30 to cause ball-bearing 65 to press downwards into open end 63, against spring 64, thereby disengaging ball- bearing 65 from groove 42 and enabling rotation of first adjustment device 30. Ball bearing 65 becomes engaged within each adjacent groove 42 as device 30 is rotated, and a click is heard upon each engagement. The precise angular adjustment of device 30 may therefore be calculated by counting the number of clicks, where the precise angular difference between adjacent grooves 42 is known. Since grooves 42 are discrete formations, not every angle can be implemented. However, the accuracy of the available angles is very high.

A second discrete adjustment device 70 for providing adjustment in a horizontal plane, is attached to adjustment device 30. Adjustment device 70 comprises a disc 72 provided with a central through-hole 74, and a downwardly directed cylindrical protrusion 76 formed on an outer radial edge of disc 72. The outwardly facing surface 78 of disc 72 is smooth, while the inwardly facing surface is provided with a series of discrete grooves 80, similar to grooves 42.

Protrusion 46 of first adjustment device 30 is insertable within through-hole 74 of second adjustment device 70 and is fixed in position by a disc 82 and a nut 84 screwed onto threaded end 48 of protrusion 46, such that disc 72 is flush with perpendicular surface 34 of first adjustment device 30, with grooves 80 facing surface 34. Protrusion 46 therefore provides a pivot on which adjustment device 70 rotates to provide angular adjustment in a horizontal plane. When second adjustment device 70 is fixed in position on protrusion 46, ballbearing 44 becomes inserted within one of the grooves 80 formed on disc 72, thereby preventing free rotation of disc 72. In order to adjust device 70, elongated member 15, when connected with base 9, is grasped in one hand and adjustment device 70 in the other. A sufficient amount of force is exerted on ball-bearing 44 to push it inwards against the action of spring 43, disengaging ball-bearing 44 from the groove 80 into which it was inserted and enabling rotation of disc 72. As disc 72 is rotated, ballbearing 44 becomes inserted within a subsequent groove 80, causing a clicking sound.

As described above with reference to first adjustment device 30, the angular adjustment can be accurately measured by counting the number of clicking sounds heard.

A dop 12 (shown in Fig. 2) for holding the diamond (not shown) to be polished and faceted is screwed onto threaded end 86 of protrusion 76. The angle of dop 12 may therefore be adjusted in both a vertical and a horizontal plane by adjustment of devices 30 and 70, enabling a diamond held by dop 12 to be presented to a polishing surface at a precisely selected angle. The adjustment can therefore be simply and accurately achieved by even an inexperienced user.

The tang arm 7 of the present invention may be used for every phase of the diamond polishing process, although, due to the sensitiveness and the high abrasion of the grooves, the most common use of this tang is during adding of small facets to the stone.

The lifetime of grooves 42 and 80 is limited due to abrasion by ball-bearings 44 and 65. In order to save costs by prolonging the lifetime of grooves 42 and 80, ball-bearings 65 and 44 may be formed of a softer material than that of discs 32 and 72, thus ball-bearings 65 and 44 will wear out instead of grooves 42 and 80. Replacing a worn out ball-bearing is more cost effective then replacing a worn out disc.

Fig. 4 shows an alternative embodiment 88 of the tang arm of the present invention, in which cost-effectiveness may be increased by replacing hole 28 of embodiment 14 by an elongated opening 90. The length of opening 90 is at least equivalent to the entire length of grooves 42. Hence, when the edges of grooves 42 become worn away at a particular point, engagement device 58 may be repositioned within opening 90 such that ball-bearing 65 is in contact with the edges of grooves 42 at an undamaged point. Disc 32 would therefore only need replacing once grooves 42 become worn out along their entire length.

Fig. 5 shows a further alternative embodiment 94 of the tang of the present invention. Embodiment 94 provides a solution for the problem of being able to apply only distinct angles as determined by the angles of the discrete grooves of discs 32 and 72.

In order to enable a continuous angular adjustment, an additional adjusting tool is combined with the tang 7 of the present invention.

In the embodiment 94 shown on Fig. 5, a continuous angle adjustment device 96 is attached to disc 72. This combination enables continuous fine adjustment of the angle of a dop with respect to the tang arm. Alternatively, any angle adjustment device known to the art which enables fine continuous taring of the angle of a dop may be used. More then one additional type of adjusting tool can be combined with the tang 7 of the present invention. .Angle adjustment device 96 is further illustrated in Fig. 6. With reference to

Fig. 6, angle adjustment device 96 further comprises mediator 110, housing 112, spring housing screw 114, spring 116, axis pin 118, axis fixating pin 120, adapter screw 122, angle adjustment screw 124 and angle limiting disc 126.

Mediator 110 has a vertical T shaped base 128 having a horizontal section 132 and a perpendicular section 133, with an elongated screw 130 extending perpendicularly upwards from the center of horizontal section 132 of base 128.

Elongated screw 130 is inserted into one end of a connector device 131 (shown in Fig.

5). Protrusion 76 of disc 72 is inserted into a second end of connector device 131, thereby connecting angle adjustment device 96 to adjustment device 70. Other methods for connecting angle adjustment device 96 and protrusion 76 should be apparent to someone of ordinary skill in the art.

Horizontal front section 134 of base 128 is provided with a central through hole 136. The diameter of through hole 136 should be large enough to allow insertion therein of axis pin 118. Vertical side section 138 is also formed with a central hole 140 extending at least to the position of through hole 136. The diameter of hole 140 is sufficiently smaller than that of axis pin 118 so as not to weaken axis pin 118 and prevent it from serving as an axis for the angular shifting of dop 12 connected with angle adjustment device 96. Housing 112 comprises a substantially cylindrical vertical portion 148 and a tapering upper section 150. A u-slot 142 is formed in the middle of cylindrical portion 148. The bottom part of u-slot 142 is a rounded thread 144. Housing 112 is further provided with a horizontal channel 146, positioned on the lower edge of tapered upper portion 150 and extending partially into cylindrical portion 148. The diameter of channel 146 is equal to the diameter of through hole 136 of mediator 110.

A mediating screw 152 extends downwards from the center of the bottom face of cylindrical portion 148 of housing 112, enabling attachment of angle adjustment device 96 to dop 12. Axis pin 118 is provided with a through hole 154, positioned at longitudinal midpoint of pin 118 and extending perpendicular to the axis of pin 118. The diameter of hole 154 is equal to the diameter of hole 140 formed in vertical side 138 of mediator 110 and complementary to that of axis fixating screw 120. The length of axis pin 118 is shorter than the diameter of housing 112, such that the ends of axis pin 118 do not extend beyond the edges of housing 112.

Mediator 110 is placed within u-slot 142 with through hole 136 and channel

146 aligned so as to form a single continuous channel. The length of perpendicular section 133 of mediator 110 should be such that when in place, the lower edge 156 of perpendicular section 133 is not in contact with the rounded thread 144 at the bottom of u-slot 142.

Once mediator 110 is in place, axis pin 118 is inserted into the continuous channel formed by through hole 136 and channel 146. Hole 154 of pin 118 is aligned with hole 140 formed in horizontal side of base 128 of mediator 110, to form a continuous channel. Axis fixating pin 120 is then inserted into the continuous channel formed by holes 140 and 154, thereby preventing axis pin 118 from slipping.

Adapter screw 122 is screwed into one side of rounded thread 144 (at this stage it is irrelevant to which of the sides adapter screw 122 is screwed, since the formation is in complete symmetry). Adapter screw 122 is a stationary part that serves as an adapter for angle adjustment screw 124. Adapter screw 122 should not be screwed too deeply into thread 144 since by doing so the angle by which angle adjustment device 96 can slant will be dramatically minimized, as will be explained below.

Spring housing screw 114 is also complementary to thread 144. Spring housing screw 114 is hollow for the purpose of containing spring 116. Spring 116 is inserted into spring housing screw 114 so that part of spring 116 is inside spring housing screw 114, and the rest of it extends therefrom. Spring 114 should be formed of a material that is difficult to contract, such that spring 114 exerts sufficient pressure on housing 112 to cause housing 112 to slant to the maximum possible degree while having a dop 12 holding a small diamond attached thereto.

Once spring 116 is inside spring housing screw 114, spring housing screw 114 is screwed into threaded hole 144 of housing 112 on the opposite side to that of adapter screw 122, so that spring 116 is pressed against the lower edge 156 of perpendicular section 128 of mediator 110. The amount of pressure exerted by spring 116 on edge 156 can be reduced and increased as necessary by screwing and unscrewing spring housing screw 114. The pressure exerted on mediator 110 is transferred to housing 112 to which mediator 110 is connected, thereby causing housing 112 to slant in the direction from which the pressure is provided, up to the maximum degree allowed by angle limiting disc 126. Angle limiting disc 126 is provided with a central threaded hole 160. The threading of hole 160 is complementary to the thread 162 of elongated screw 130 of mediator 110. Angle limiting disc 126 is screwed over elongated screw 130. The thread 162 of elongated screw 130 does not reach the base 128 of elongated screw 130. The distance between the end of the thread of elongated screw 130 and the base 128 thereof is determined in accordance with the maximum slanting angle desired. The closer the end of the threading to the base of elongated screw 130, the narrower the slanting angle of angle adjustment device 96.

In accordance with the preferred embodiment, the threading 162 of elongated screw 130 ceases 1.5 mm above base 132. Instead of using different elongated screws 130 having different thread lengths, angle-limiting disc 126 can be screwed up to a desired position on the thread 162 of elongated screw 130.

Adapter screw 122 is provided with a central threaded channel 162, complementary to the thread of angle adjustment screw 124. Angle adjustment screw 124 may therefore be screwed into channel 162 of adapter screw 122. When angle adjustment screw 124 is completely unscrewed, housing 112 is slanted in the direction from which pressure is applied by spring 116, as described above. When angle adjustment screw 124 is fully screwed into adapter screw 122, adjustment screw 124 presses against the opposite side of perpendicular section 128 of mediator 110 to that on which pressure is exerted by spring 116, thereby pulling housing 112 towards angle adjustment screw 124

Once angle adjustment device 96 is fully assembled, as described above, there are two opposite sources of pressure exerted one on each side of perpendicular section 128 by spring 116 and angle adjustment screw 124. The pressure exerted by angle adjustment screw 124 is stronger than that exerted by spring 116, since spring 116 will contract in response to counter pressure exerted by angle adjustment screw 124, causing housing 112 to slant in the direction of pressure exerted by angle adjustment screw 124. As angle adjustment screw 124 is unscrewed, spring 116 will be allowed to expand, pulling housing 112 in its direction. Therefore, once angle adjustment device 96 is assembled, the slanting of housing 112 is controlled by angle adjustment screw 124.

Fig. 7 shows the tang arm 94 of Fig. 5 comprising a discrete angle adjustment device 70 and a continuous angle adjustment device 96, in conjunction with a dop 12 and a base 9, having legs 174.

The combination of discrete angle adjustment device with a continuous angle adjustment device enables an operator to simply and accurately achieve any desired angle of inclination of a diamond dop in relation to the horizontal portion of a tang. A high quality level of diamond polishing can therefore be achieved by even an inexperienced operator.

Claims

We claim:

1. A tang for holding a dop during polishing of diamonds, the tang comprising: a support member; and a discrete angle adjustment device connected with said support member, enabling discrete angular adjustment of the dop.

2. The tang of claim 1 further comprising: a continuous angle adjustment device connected with said discrete angle adjustment device, mediating between said angle adjustment device and the dop.

3. The tang of claim 1 wherein said discrete angle adjustment device comprises: a first rotatable device fixedly connected with said support member, said rotatable device being formed with a pattern of discrete, radially extending grooves on an outer surface; and a first engagement element extending from said support member for patterned engagement of said discrete grooves of said first rotatable device, such that upon rotation of said first rotatable device, a portion of said first engagement element becomes inserted within a subsequent one of said grooves thereby producing an audible click, such that an indication of angular adjustment in a first plane may be obtained by counting of said clicks.

4. The tang of claim 3 wherein said first rotatable device is arranged coaxially with said support member and is formed with a second engagement element on a forward-facing surface, said tang further comprising: a second rotatable device arranged perpendicular to said first rotatable device, said second rotatable device formed with a pattern of radially extending, discrete grooves engagable by said second engagement element of said first rotatable device, wherein upon rotation of said second rotatable device, said second engagement element of first rotatable member engages a subsequent one of said grooves of said second rotatable device, thereby producing an audible click, such that an indication of said angular displacement in a second plane may be obtained by counting of said clicks.

5. The tang of claim 3 wherein said first rotatable device comprises a shaped protrusion for attachment thereto of the dop.

6. The tang of claim 1 wherein said support member comprises a substantially planar horizontal upper surface, a pair of downwardly- directed vertical side sections extending from said horizontal upper surface, and a forked front end for retention therein of said first rotatable device.

7. The tang of claim 6 wherein one side of said forked end is provided with a through-hole for retention therein of a first end of said first engagement element such that a second end of said first engagement element is engaged within one of said grooves of said first rotatable device.

8. The tang of claim 7 wherein said through-hole has an elongated formation such that said engagement device may be positioned at any point therein.

9. The tang of claim 3 wherein said first rotatable device comprises a backwardly-directed semicircle combined with an orthogonally-arranged straight vertical and horizontal edge, said second engagement element being positioned on an upper section of said vertical edge.

10. The tang of claim 4 wherein said second rotatable device comprises a disc and wherein said grooves are formed extending radially inward from the circumference of a backward-directed face of said disc.

11. The tang of claim 10 wherein said vertical edge of said first rotatable device is provided with an elongated threaded protrusion and wherein said disc of second rotatable device is formed with a central threaded opening, such that said protrusion is insertable within said threaded opening of said disc.

12. The tang of claim 11 wherein said disc of second rotatable device is fixedly attached against said vertical edge of said first rotatable device by a nut screwed onto the end of said protrusion of first rotatable device inserted through central opening of said disc.

13. The tang of claim 6 wherein a pair of oppositely positioned through holes are formed one in each side of said forked end, wherein said first rotatable device is provided with a central through-hole for alignment with said forked end through-holes, such that said first rotatable device may be fixedly mounted within said forked end by insertion of a bolt through said aligned through- holes of said forked end and said first rotatable device.

14. The tang of claim 4 wherein said second rotatable device is provided with a shaped protrusion for attachment thereto of the dop.

15. The tang of claim 3 wherein a spring-loaded ball bearing is positioned at said second end of said first engagement element.

16. The tang of claim 4 wherein said second engagement element comprises a spring-loaded ball-bearing positioned within a channel formed on said vertical surface of said first rotatable device.

17. The tang of claim 2 wherein said continuous adjustment device comprises: a housing; a mediator contained within said housing in contact with inner surface of said housing; and a spring loaded screw-operated adjustment mechanism for adjustment of angle of mediator, such that said angle of said housing is altered by adjustment of said adjustment mechanism.

18. A discrete angle adjustment mechanism for use during polishing of diamonds.

19. The mechanism of claim 18 comprising: a first rotatable device fixedly connected with said support member, said rotatable device being formed with a pattern of discrete, radially extending grooves on an outer surface; and an engagement element extending from said support member for patterned engagement of said discrete grooves of said first rotateable device, such that upon rotation of said first rotatable device, said element becomes inserted within a subsequent one of said grooves thereby producing an audible click, such that an indication of angular adjustment in a first plane may be obtained by counting of said clicks.

20. A method of holding a dop during polishing and faceting of small diamonds, the method comprising: providing a tang comprising a unitary elongated body and a discrete angle adjustable device fixedly attached to said elongated body, and to the dop; and adjusting the angle of said adjustable device, thereby adjusting the angle of the dop.