US2724220A - Faceting device for gem stones - Google Patents

Description

Nov. 22, 1955 L. E. SHAW 2,724,220

FACETING DEVICE FOR GEM STONES Filed y 50, 1951 6 Sheets-Sheet 1 20 IO 2| '6 2 L i v 4e Fl 6-. 6

LOUIS EATON SHAW Nov. 22, 1955 1.. E. SHAW 2,724,220

FACETING DEVICE FOR GEM STONES Filed July 50, 1951 6 Sheets-Sheet 2 FIG.Z

LOUIS EATON SHAW INVEN TOR Nov. 22, 1955 1.. E. SHAW 2,724,220

FACETING DEVICE FOR GEM STONES Filed July 30, 1951 6 Sheets-Sheet 3 FIG.3

LOUIS EATON SHAW IN VEN TOR.

I Nov. 22, 1955 E. SHAW 2,724,220

FACETING DEVICE FOR GEM STONES Filed July 30, 1951 6 Sheets-Sheet 4 FIG.4

LOUIS EATON SHAW IN V EN TOR.

Nov. 22, 1955 L. E. SHAW 2,724,220

FACETING DEVICE FOR GEM STONES Filed July 30, 1951 6 Sheets-Sheet 5 IIIIIIIHHIF LOUIS EATON SHAW INVENTOR.

Nov. 22, 1955 L. E. SHAW 2,724,220

FACETING DEVICE FOR GEM STONES Filed July 30 1951 6 Sheets-Sheet 6 I I 45 P L.

LOUIS EATON SHAW INVENTOR.

United States Patent FACETIN G DEVICE FOR GEM STONES Louis Eaton Shaw, Newark, N. J. Application July 30, 1951, Serial N 0. 239,254

8 Claims. (Cl. 51-125) The present invention relates to a faceting device for gem stones and the primary object of the invention is to provide a device for cutting or forming the facets on gem stones by means of which a person without previous experience may properly cut the facets on gem stones with an accuracy equal, or superior, to that obtained by professional lapidaries.

For many years the cutting and polishing of gem stones has required the development of a high degree of manual skill, since the apparatus employed has no provision for insuring accuracy in the angles of the facets as measured either in relation to the axis of the stone or to their spacing around the circle.

In carrying out the customary method of faceting stones, the apparatus used consists of three essential elements: an accurately machined circular metal disc known as a lap revolving on a vertical axis; a wooden dop stick or dop, five or six inches long, of circular cross section about one-half inch in diameter near the center and tapering toward the ends, to one end of which the stone is cemented; and an inverted cone of wood, known as a jam peg," mounted vertically beside the lap but not touching it. The jam peg is provided with a row of shallow holes, closely spaced, into any one of which the end of the dop stick opposite the stone may be placed.

' Inoperation, with the lap revolving, the dop is so grasped by the fingers of one hand of the cutter, that the thumb and forefinger are close to, if not actually touching, the stone. -The opposite end of the dop is then placed in one of the holes of the jam peg and the stone lowered into contact with the lap which has been previously coated with an abrasive. It is self-evident that with a dop stick of a given length, the angle at which the stone contacts the lap will be determined by the height of the hole into which the rear end of the dop has been inserted.

It is customary to first cut and polish the.table," or large facet on the top of the stone, either by holding the stone in the fingers and pressing it first against a cutting lap and then against a polishing lap, or by mounting it as an angle on a dop and following the procedure above de scribed. After the table or large facet has been formed on the stone it is then cemented to a dop with the table" at right angles to the axis of the dop in orderto cut the side facets.

Assuming, therefore, that the table has been cut and polished, and that the stone has been properly mounted as above described, the rear end of the dop is inserted into one of the holes on the jam peg and the first facet cut to what appears to be the proper depth. The dop is then turned in the fingers and a second facet cut on the opposite side of the stone. Other facets are then out between the first two until the desired number has been produced. It is evident that accuracy in the locating and cutting of the facets depends entirely on the lapidarys ability to cut each one just the right depth, and to rotate the dop through the exact number of degrees necessary to give the proper spacing. Good eyesight and a sensitive touch are of star.

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equal importance with long training in carrying out this customary method of faceting stones.

One of the simplest, as well as the most common forms of facet cut gems is the brilliant. Stones cut in this form are termed round, though they actually have sixteen sides. The periphery, or girdle may be likened to the equatorial line around the earth through which the axis extends. Viewed from one side, with the girdle horizontal and the axis vertical, all of the stone above the girdle is called the crown, while all below the girdle is called the pavilion. The crown is flat on the top to form the table while the sides of the pavilion extend downward to a point. To minimize the chances of breakage the point is sometimes not left quite sharp but is fiatened oft slightly, thus forming a tiny facet known as the culet.

In the case of a brilliant this first row of facets would be eight in number, and would be cut at an angle varying with the index of refraction of the stone. With the quartz grouping, that is amethyst, citrine, rock crystal, carnelian, etc. This angle would approximate forty-five degrees. They constitute the main facets ofthe crown or, simply the mains. Next come the star facets, also eight in number adjacent to the table. To cut these, the rear end of the dop is placed in a hole farther up on the jam peg, thus giving them a greater angle with the axis. They are located on the lines dividing the mains and are triangular in form. When viewed as a group from a point above the table the effect is of the outlines of two squares superimposed at an angle of 45 forming an eight-pointed To. complete the crown, the rear end of the dop is placed in a lower hole in the jam peg and a total of sixteen break facets formed, each of which is triangular in outline and extends from the points of the star facets to the girdle. As thesev are cut, the mains assume a kite shape.

Altogether there are thirty-three facets on the crown; eight mains; eight stars; 16 breaks and the table. The stone is now turned over on the dop and the pavilion facets cut in the same manner except that the pavilion has only mains and breaks, twenty-four in all.

An object of the present invention is to provide a device including a rotating lap and various other mechanisms which may be accurately adjusted so as to permit a person without previous experience, or who has not acquired the ability to cut gems manually or by hand as do the professional lapidaries, to cut the facets accurately on gems and turn out work of good quality.

Another object of the invention is to provide apparatus for faceting gem stones which is of simple but versatile form, light in weight yet rigid in construction, is easily kept clean and easily manipulated.

. Another object of the invention is to provide an apparatus as specified in which accuracy in the cutting and polishing of gem stones is provided and maintained by supporting the lap, the dop, and the dop holder or faceting head" by the same structure.

Another object is to provide mechanical means whereb a stone after being mounted on a dop, may be accurately positioned relative to the cutting surface of the lap,

both as to angular position of its axis therewith, and also as measured in degrees around its periphery or girdle.

A further object of the present invention is to provide means whereby a dop, with stone attached, may be removed from the faceting head and later replaced quickly and accurately in its original position.

A further objectof the invention is to provide mechanical means whereby all of the facets in any row around the stone may be cut to the same angle and depth without resort to external measuring devices and to provide an apparatus whereby any number of stones may be cut to identical size and shape.

A further object of the invention is to provide means for transferring a stone from one dop to another, be: tween the cutting of the crown and the cutting of the pavilion, in a a manner that will insure the correct alignment of all the facets.

Another object of the invention is to provide a faceting head with a rotatable dop holder provided at one end with a flange notched to receive a locating latch and at the opposite end with a series of notches for receiving a locating pin on the dop, whereby the obtainable angular positions are multiplied. For example, with twenty-four notches in the flange and four in the end of the dop opposite, a total of ninety-six divisions is available.

With these and other objects in view, as may appear from the accompanying specification, the invention consists of various features of construction and combination of parts, which will be first described in connection with the accompanying drawings, showing a faceting device for gem stones of a preferred form embodying the invention, and the features forming the invention will be specifically pointed out in the claims.

In the drawings Figure 1 is a front elevation of the lap and faceting head supporting structure of the apparatus for faceting gem stones.

Figure 2 is a top plan view of the structure shown in Figure 1 of the drawings.

Figure 3 is a vertical section through the structure shown in Figure 1 of the drawings, that is, through the lap plate supporting structure and the faceting head supporting table.

Figure 4 is a fragmentary view partly in section and partly in side elevation showing the faceting head supported upon the faceting head supporting table and a gem stone in'position for the cutting of a facet on the lap plate or disc.

' Figure 5 is a top plan of the faceting head.

Figure 6 is a fragmentary longitudinal section through the faceting head taken on the line 6-6 of Figure 5.

Figure 7 is a cross section through the faceting head taken on the line 7-7 of Figure 5. 3

Figures 8, 9 and 10 are details of the latch which cooperates with the notched flange on the dop holder.

' Figure 11 is a side elevation of a dop holder.

Figure 12 is an end view of the dop holder.

Figure 13 is an end view of the dop holder showing the opposite end to that illustrated in Figure 12.

'Figure 14 is a plan view of a dop employed in the invention.

Figure 15 is a side elevation partlyin section of the dop. Figure 16 is an end view of the dop. Figure 17 is a top plan of a device employed for accurately transferring the gem stone from one dop to. another.

Figure 17a is a view illustrating the manner of transferring a stone from one dop to another.

Figure 18 is a side elevation of the device to facilitate accurate transfer of a gem stone from one dop to another,

Figure 19 is an end view of the device shown in Figures 17 and 18.

Referring more particularly to the drawings, the structure shown in Figures 1, 2 and 3 forms a body portion or what might be called the supporting structure of the gem faceting device. This body portion includes a central bowl-shaped member 1 from which two arms 2 and 3 extend laterally and horizontally. At the center of the bowl 1 is an upstanding axial bearing support 4 which carries a pair of spaced ball bearings 51. A spindle 6 is rotatably carried by the bearings 5 and projects below the bottom of the body portion or supporting structure o as. to p rm c n t n f h sp d e i ny s able type of drive mechanism for rotating the spindle. A circular lap plate or lap 7 is carried by the upper end of the spindle 6 on which it is removablymounted. The

4- lap 7 is clamped against the positioning member 8 and is held in place on the spindle 6 by a clamping nut 9 and washer 1G. The positioning member 8 maintains the upper surface of the lap 7 always at right angles to the axis of the spindle 6.

Each of the laterally extending arms 2 and 3 has a collar 11 formed thereon at its outer end which carries a threaded sleeve 12. A key 13 is carried by the sleeve 12 and engages in a keyway 14 of the stem 15. A table 16 is carried by the stem 15 and it rests upon an adjusting nut 17 threaded on the sleeve 12. A hand ring 18 is formed on the nut 17 for facilitating its rotation to adjust the table 16 axially relative to the sleeve 12 and to adjust the position of the upper plate face 19 of the table relative to the upper fiat face of the lap 7. Two laterally extending arms 2 and 3 extend in opposite directions from the axis of the spindle 6 so as to permit use of the table 16 on either the right or left hand side of the operator as found most convenient and at the same time to provide support for a tray 20 on which dishes or containers forabrasive or polishing powders, water, etc. may be placed.

The tray 20 is shiftable from one arm to the other, as is the table 16.

The bowl-shaped member 1 has a splash ring 21 set loosely in the upper counterbored rim 22 of the bowl and the bowl receives drippings or excess water or liquid from the lap 7 which is drained from the bowl through an outlet 23.

The bowl 1 has three supporting legs or feet 24 attached thereto which rest upon a surface indicated at A, such as a table or the like, on which the device is used. As clearly shown in Figure 3 of the drawings the table 16 has an annular upstanding rim 25 thereon the purpose of which will hereinafter appear.

It is evident from the above and from Figures 1 and 3 of the drawings that the surface 19 of the table 16 will be parallel to the upper surface of the lap 7 irrespective of the axially adjusted position or vertically adjusted po: sition of the table 16 even though the apparatus is mounted on a surface that is not exactly level. This is important, since the stone holder or faceting head 30 shown in Figures 4 and 5 of the drawings, rests on, and is positioned by, the table 16, and if the two surfaces were not parallel, the angles to which the faceting head were set would not be the angles to which the facets were cut.

The faceting head 30, which forms a component part of the apparatus supports the stone to be cut and it consists of a frame member 31 having a central connecting por: tion 32, a yoke 33 and a pair of laterally extending arms 34 at the end of the central portion remote from the yoke 33. Three levelling screws 35, 36 and 37 are carried by the frame 31, the levelling screws 35 and 36 being carried by the arms 34, while the levelling screw 37 is carried by the central member 32 at its junction with the yoke 33.

Trunnion screws 38 pivotally support a tilting member- 42 to facilitate positioning of the tilting member 39 at the proper angle for cutting the diiferent facets on a gem,

stone. The thumb screw also acts as a locking means for locking the tilting member 33 in its selected position relative to the quadrant 41.

The tilting member 39 includes a sleeve 44 into which a c 5 serted nd i wh h i is h ld n place by l mp s re 4.2 T e dop h ld r 9. s a flan e 6 rm there hi h h a'plu lity of t hes 47 ut.

n its Pe imeter The flang 6 is P s t o ed near ne end of the dop holder as clearly shown'in Figures 6 and 11 of the drawings and the opposite end of the dop holder is provided with one or more notches 48. to receive a locating pin 49 carried by the dop 45. A spring pressed latch 50 is pivotally carried by the tilting member 39 and one end of the spring pressed latch 50 is urged into one of the notches 47 of the flange 46 by the spring 51 being removed therefrom by manual pressure on the thumb piece 52 of the latch. g p

One end of the dop 45 is knurled as shownat 55 to facilitate the cementing of a stone to the end of a dop as is shown in Figure 4 of the drawings.

Assuming that a dop 45 having a stone, as indicated at 60, cemented to its end has been inserted into the dop holder 40 andit isdesired to cut and position the table of the gem stone. Since it is customary to measure facet angles on a gem stone in relation to the plane of the table and girdle, instead of in relation to the axis of the stone, the protractor is calibrated accordingly and therefore the dop holder would be adjusted to the zero mark on the protractor. The faceting head 30 would then be placed on the table 16 and the height of the table adjusted with the levelling screws 35 and 36 resting on the table and the levelling screw 37 would just clear the surface of the table as shown in Figure 4 of the drawings. Rotation of the lap would then be started and the faceting head, held with the operators hand would be manipulated to move the stone back and forth across the face of the lap until a portion of the stone had been cut away and the levelling screw 37 had contacted the top of the table 16 to put an end to the cutting of the stone. The cutting lap 7 would then be replaced bya polishing lap and the height of the table 16 adjusted until the gem stone came in contact with the lap surface. At this point the levelling screw 37 would be retracted slightly or the faceting head moved to the left a sufiicient distance to bring the screw 37 outside of the rim 25 of the table 16 so that the weight would be carried by the stone and the two righthand levelling screws 35 and 36. Since all laps, and particularly polishing laps, which are made of soft metals such as lead or tin, are apt to wear to a slightly conical shape, the table of the stone may not contact the lap evenly over its entire surface, a condition discernible after a few seconds of polishing. If, for instance, inspection showed that the side of the facet nearest the operator was not contacting the lap, the righthand levelling screw, that is, the screw 35 or 36 nearest the operator would be retracted enough to compensate forthis condition. Or polishing might not be taking place on the side of the facet farthest to the left, in which case the table 16 would be raised slightly to bring the entire surface of the facet into intimate contact with the lap. In some instances, adjustment of boththe table and one or the other of the levelling screws might be advisable.

If it should be desired to cut the stone in a brilliant shape, hereinabove more specifically described, a dop holder having eight notches in its flange and four notches in its opposite end would be used. It should beunderstood that dop holders having various combinations of notching would be needed for stones of different shapes or spacing of facets, and that substitution of one dop holder for another is quickly and easily accomplished by looseningthe set screw 61 in the locking collar 62 and removing the collar after which the dop holder may be withdrawn from the tilting member 39 and a replacement inserted. 'To meet special conditions the flange 46 of the dop holder may be graduated in degrees, or arbitrarily, thedivision lines being numbered or otherwise identified as shown in Figure 13 of the drawings, and the dop holder set by bringing the desired'line into registration with a line described on the endof the tilting member. It wouldthen be lockedagainst turning by means of a sf ct screw threaded into the latter as shown at 46" in'Figure 5. In cases such as this a single notch 48 might be" all that is necessary in the end of the dop holder opp o site the flange, to enable a number of similar stones to be car- 6 ried through the one operation before achange is made in the position of the dop holder. v

To cut a brilliant a dop 'holder having eight notches 47 in its flange and four notches 48 in its opposite end would be employed. -One of the four notches 48 would be in line with the zero notch 47' of the flange and would be designated by the letter M (see Figure 12) signifying main. The other three notches 48 as shown in Figure 12 of the drawings would be designated S, B, and B. To cut the eight main facets therefore, the locating pin 49 on the dop would be placed in the M notch 48 and the thumb screw 46 tightened. The tilting member 39 would then be adjusted to the desired angle (for instance 43"; on the protractor 41), the supporting table height adjusted in the manner previously described, and the first facet cut. The latch 50 would then be raised, the dop holder turned one division, and the second facet out After all of the eight main facets have been cut in this manner the thumb screw 46' would be loosened, and the dop turned until its locating pin 49 was in the notch marked S and the thumb screw would then be retightened. The tilting member would be adjusted to the proper angle (say 25), the height of the table 16 adjusted, and the eight star facets cut. I

To cut the break facets there are two notches in the end of the dop holder 40, each marked with the letter B. When the locating pin 49 of the dop45 is in one of these notches, and the tilting member adjusted to the proper angle (approximately 49) the break facets to theright of the mains will be cut, and when the locating pin is placed in the other B notch the break facets to the left of the mains will be cut. Reference to Figures 12 and 13 shows how the notches 47 in the flange 46 and the notches 48 in the opposite end of the dop holder'are located in relation to one another. This is the diag'ram'ifor a brilliant cutting and it is seen to have thirty-two equal divisions, the main being located at 0, 4, 8, 12, 16,20, 24 and 28. The stars are at 2, 6, 10, 14, 18, 22, 26 and 30, while the breaks are at l, 3, 5,7, 9,11, 13,15, 17, 19, 21, 23, 25, 27, 29 and 31. The numbers'just above stated refer to the numbers on the flange 46 as seen in Figure 13 of the drawings. I

Instead of placing the letters M, B, B and S of the various notches on the small end of the dop holder where there is but little space available, the letters may be placed on the hub of the flange 46 and a V-mark made on'the rear end of the dop in line with the locating pin. When locating the dop in the holder it is' thus only necessary to rotate it in one direction or the other until the locating pin enters the notch that brings the V-mark, indicated at in Figure 14 of the drawings, opposite the letter cor-. responding with the type of facets to be cut. These letters M, B," B, and S are shown in place in Figure 13 of the drawings. j H v When a stone is to be cut the first operation is that of attaching it to a dop and aligning it therewith by means of the fixture shown in Figures 17, 18 and 19 of the draw-; ings. This fixture comprises a main body which has a pair of aligning blocks 71 and 72 formed thereon, the

facing ends of which are spaced to form the gap 73. Each of the blocks 71 and 72 has a longitudinally extending Y-I notch 74 cut in its upper face and. after the stone has been attached to a dop 45'and while the cement 75 is still soft the dop is placed in the V -notch 74 of one of the blocks. In Figure 17 it is shown placed in the V-notch of the block 71 and the top surface or table indicated at 76 against the end of the dop 45 and by'rotating the dop 45 in the V-groove the stone may be checked for lateral misalignment by means of the adjustable alignment gage or blade 77 vwhich-is pivotally connected to the block 72 and is held in adjusted position by means of a spring 78. Contact of the top surface orftabl'e ot the stone" with the end of dop 45 forces itinto a plane at right angles to the axes of the dops. This is done 'with' the dop 45 well to the left of the position shown in Figure 1711111 order that the locating pin 49 of the dop 45 may come within the gap 73 and thus permit dop 45 to be turned through 360". After the stone has been properly checked the dop is clamped in place by means of the pivoted clamp structure 79 pivotally carried by the block 71 and including the clamping screw Sfi which is adjusted to force the dop 45 firmly in the V-groove 74. The dop 45' to which the stone is to be attached is then heated, dipped in thermo-plastic cement, laid in the groove of the V-block 72 and quickly pushed into contact with the. stone. For this part of the operation the locating pins 49 of both the dops are held in contact with the fiat upper surface of the aligning blocks 71 and 72 respectively. Dop 45' is then allowed to remain there until the cement has" hardened, it being held securely in place by means of the pivotally mounted clamp 79 and clamping screw 80 carried by the block 72. When the cement is hardened. thetwo dops and the stone are removed from the V- blocks as a unit and the first dop heated until it may be pulled free from the stone. Any cement adhering to the stone is then scraped off and the cutting of the pavilion facets may then proceed in the manner described for cutting those of the crown except, as hereinabove stated, there will be no stars.

I By transferring the stone from one dop to another in this manner, the correct alignment of the facets of the crown and of the pavilion is assured; that is, the mains of the pavilion will be directly in line with the mains" of the crown.

It will be understood that the invention is not to be limited to the specific construction or arrangement of parts shown, but that they may be widely modified within the invention defined by the claims.

" What is claimed is:

1. In a faceting device for gem stones, at body portion including a supporting member, a lap plate rotatably carried by said supporting member, a radiating arm attached to said supporting member, a stationary sleeve carried by said arm and having its axis parallel with the axis of rotation of the lap plate, an adjustable sleeve adjustably carried by said stationary sleeve, a faceting head supporting table carried by said first sleeve for axial non-rotary movement relative to said first sleeve and engaged by said adjustable sleeve to adjust the position of the table axially relative to said lap plate.

2. In a faceting device for gem stones, a body portion including a bowl-shaped member, a lap Plate rotatably carried by said bowl member, a radiating arm attached to said bowl member, a stationary sleeve carried by said arm and having its axis parallel with the axis of rotation Y of the. lap plate, an adjustable sleeve adjustably carried by said stationary sleeve, a second radial arm attached to said bowl member, a first sleeve carried by said second radial arm and an adjustable sleeve adjustably carried by said first sleeve carried by said second radial arm.

3, In a faceting device for gem stones, a body portion including a bowl-shaped member, a lap plate rotatably carried by said bowl member, a radiating arm attached to said bowl member, a stationary sleeve carried by said arm and having its axis parallel with the axis of rotation of the lap plate, an adjustable sleeve adjustably carried by said stationary sleeve, a faceting head supporting table carried by said first sleeve for axial non-rotary movement relative to said first sleeve and engaged by said adjustable sleeve to adjust the position of the table axially relative to said lap plate, and a splash ring carried by said bowl member and surrounding said lap plate.

4. In a faceting device for gem stones, a body portion including a supporting member, a lap plate rotatably carried by said. s pp g m m r, a ra iating rm. t-

to said supporting member, a stationary sleeve earried by said arm and havingfits 'axis parallel with the. axis of rotation of the lap plate, an adjustable sleeve adjustably carried by said stationary sleeve, a faceting head supporting table carried by said first sleeve for axial nonrotary movement relative to said first sleeve and. engaged by said adjustable sleeve to adjust the position of the table axially relative to said lap plate, said faceting head supporting table having a flat upper surface which is at all times parallel with said rotary lap plate, and a faceting head freely movable over the upper fiat surface of said table independently of'rnovement of the table.

5. In a faceting device for gem stones, a body portion including a supporting member, a lap plate rotatably carried by said supporting member, a radiating arm attached to said supporting member, a stationary sleeve carried by said arm and having its axis parallel'with the axis of rotation of the lap plate, an adjustable sleeve adjustably carried by said stationary sleeve, 8. faceting head support ing table carried by said first sleeve for axial non-rotary movement relative to said first sleeve and engaged by said adjustable sleeve to adjust the position of the table axially relative to said lap plate, said faceting head supporting table having a flat upper surface which is at all times parallel with said rotary lap plate, a faceting head freely movable over the upper flat surface of said table independently of movement of the table, said faceting head including a carrying frame, and a plurality of independently adjustable levelling screws adjustably carried by said frame for engagement with the flat upper surface of said table.

6. In a faceting device for gem stones, a body portion including a supporting member, a lap plate rotatably carried by said supporting member, a radiating arm attached to said supporting member, a stationary sleeve carried by said arm and having its axis parallel with the axis of rotation of the lap plate, an adjustable sleeve adjustably carried by said stationary sleeve, a faceting head supporting table carried by said first sleeve for axial non-rotary movement relative to said first sleeve and engaged by said adjustable sleeve to adjust the position of the table axially relative to said lap plate, said faceting head supporting table having a flat upper surface which is at all times parallel with said rotary lap plate, and a faceting head freely movable over the upper flat surface of said table independently of movement of the table, said faceting head including a carrying frame, a tilting member pivotally supported by said frame, a dop holder carried by said tilting member, and indexing means for holding said dop holder in rotatably adjusted positions relative to the tilting member.

7. In a faceting device for gem stones, a body portion including a supporting member, a lap plate rotatably carried by said supporting member, a radiating arm attached to said supporting member, a stationary sleeve carried by said arm and having its axis parallel with the axis of rotation of the lap plate, an adjustable sleeve adjustably carried by said stationary sleeve, a faceting head supporting table carried by said first sleeve for axial non-rotary movement relative to said first sleeve and engaged by said adjustable sleeve to adjust the position of the table axially relative to said lap plate, a faceting head freely movable in all directions on said supporting table and including a frame, a tilting member pivotally carried by said frame, a dop holder rotatably carried by said tilting member, a positioning flange on said dop holder and provided with a plurality of positioning notches therein, means carried by said tilting member for engagement in said notches for holding said dop holder in adjusted rotary positions, said dop holder having a plurality of dop positioning notches in one end thereof, a dop, a positioining pin carried by said dop for engagement in the notches in the dop holder, a graduated quadrant on said frame, and locking means forlocking said tilting member in adjusted positions relative to said quadrant.

8. In :{tifaceting device. for gem stones, 8. body portion including a supporting member, a lap. plate rotatably carried by said supporting member, a radiating arm attached to said supporting member, a stationary sleeve carried by said arm and having its axis parallel with the axis of rotation of the lap plate, an adjustable sleeve adjustably carried by said stationary sleeve, a faceting head supporting table carried by said first sleeve for axial non-rotary movement relative to said first sleeve and engaged by said adjustable sleeve to adjust the position of the table axially relative to said lap plate, a faceting head freely movable in all directions on said supporting table and including a frame, a tilting member pivotally carried by said frame, a dop holder rotatably carried by said tilting member, a positioning flange on said dop holder and provided with a plurality of positioning notches therein, means carried by said tilting member for engagement in said notches for holding said dop holder in adjusted rotary positions,

said dop holder having a plurality of dop positioning notches in one end thereof, a dop, a positioning pin carried by said dop for engagement in the notches in the dop holder, a graduated quadrant on said frame, and locking means for locking said tilting member in adjusted positions relative to said quadrant, a plurality of inde- 1 10 pendently adjustable levelling screws adjustably carried by said frame for engagement with said table to regulate the horizontal position of the faceting head relative to the upper surface of the table.

References Cited in the file of this patent UNITED STATES PATENTS 231,577 Hessels Aug. 24, 1880 775,567 Kneip Nov. 22, 1904 1,103,698 Soetens July 14, 1914 1,168,710 Coleman Jan. 18, 1916 1,261,766 Challet Apr. 9, 1918 1,730,767 Havlicek Oct. 8, 1929 2,206,229 Kruger et a1. July 2, 1940 2,353,131 Ford July 11, 1944 2,382,099 .Rothauser Aug. 14, 1945 2,391,979 Kershaw Jan. 1, 1946 2,530,421 Burness et a1. Nov. 21, 1950 2,579,666 Hans Dec. 25, 1951

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