Turned Buttons.—Buttons made from ivory, bone, horn, woods, and such like substances, are turned in a button lathe (Fig. 431), and the holes, varying in number from two to four, are drilled, while the bntton is io the lathe, by means of long drills converging towards the button and forming all the holes at once. The cutter of the lathe is like a centre-bit, only both wings are cutters instead of one being a router. On the tool revolving, the centre pin transfixes the stance, and the wings circulating cut out a round disc, which is a,dvanced towards the cutter by a sliding bar in the back poppet head. In the machine represented in the figure, the moving javv of the clutch is forced against the blank hy a spring, 8,nd drawn back again by a depression of the treadle. The bits are brought singly and alternately against the blank, being moved thereto by the bell crank hand-lever. The woods chiefly employed are ebony, boxwood dyed black, and cocoa-wood. The so-called vegetable ivory or Corozo (Corosso, Corusco) nut consists of the hardened albumen of the interior of the nut, which the fruit of a species of palm, Phytelephas macrocarpa, imported from the northern part of South America and from Central America. The nut grows in bunches as large as the double flat, but less than half of it is fit for use. It is milky white, lighter and softer than ivory, easily turned, and will take any shade of dye. Its value is about 25/. to 30/. per ton. (See Nuts.) Button-moulds.—These are little turned wooden discs perforated in the centre, and exactly resembling miniature quoits in appearance. They form the shell over which a covering of cloth or other textile fabric may be sewn, so that the pattern can always resemble that of the garment on which the button is used. They are principally made in the south of France, where suitable wood is not expensive, a,nd are imported into this country by millions. They axe used almost exclusively on women's and children's attire.
Button Machinery.—During the last four or five years, several improvements have been effected in button making and ornamenting machinery, the principal of which will now be described.
An ingenious invention for polishing or finishing buttons made of horn, bone, wood, or Corozo nut, consists in subjecting them to frictional contact with prepared chalk, pulverized charcoal, or other fine cutting material, mixed with spirits of turpentine, naphtha, or such other liquid as, unlike ws ter, will not " raise the grain" of the substance of which the buttons a,re made. They are by this means brought to s better finish in a few hours than was hitherto possible in several days. When it is designed to ornament the buttons by " lining " or marking them with sharply-deflned annular lines, they are subjected to frictional contact under pressure of a die having an axial movement, by which, in addition to securing the requisite smooth surface, the colour of any dyes previously applied is rendered more vivid and bright, a,nd the " lines " are made without the raggedness of contour resulting from the use of a cutting tool.
Fig. 432 shows a vertical section of the apparatus employed in polishing and " lining " buttons, on the line x x, Fig. 433, which is a horizontal section on the line y y of Fig. 432. In practice, the buttons are taken either as they come from the lathe, or, when coloured, as they come from the dye, a,nd any desired number are mixed with about twice their volume (more or less) of prepared chalk, or other flue polishing substance ; to the whole, is added a quantity of spirits of turpentine, or naphtha, or, failing these, alcohol or kerosene may he used, but with inferior results. The mass is then placed in a common tumbling box, which is made to revolve for several hours, varying according to circumstances, and continued until the requisite smoothness of surface has been obtained.
The bed A is provided at its forward end with a flat circular disc or carrier plate B, furnished at its periphery with radial teeth a, and, concentric vvith its axis, with an annular series of holes b, these holes having a dimension and form corresponding with those of the articles to be polished, and extending quite through the carrier plate. The carrier plate itself is furnished with a downwardly projecting axial shaft c, which works in a bearing formed in the fixed plate C, which last closes the lower ends of the holes b, except as presently described.
At the baek of the plate C, is a vertical guide a', in which worke a lifter D. Upon the upper end of this lifter, and within the guide, rests tbe die E, while around the upper portion of tbe guide, is a steam chamber b', furnished with steam pipes d connecting with a generator, and designed to heat the die E by circulating steam through the chamber. Arranged vertioally, coincident with the lifter D and the die E, is a rotating die F, working in bearings provided in the lower part of the sliding head G, which moves in suitable guides A' fixed upon tbe bed A. This head carries an upright shaft G', upon the upper extremity of which are fast-and-loose pulleys C and B', and which carries at its lower end a pinion D', gearing into a spur wheel F' on the rotating die F. The pulleys have a belt G* running to a shaft. The position of the two dies E F is such that, as the carrier plate B is intermittently rotated, the holes b will pass in succession immediately between the dies, to permit the upper or rotating die to pass through the holes, to act in conjunction with the lower die, which remains fixed except when lifted to discharge the finished articles. A slot is formed in the plate 0, coincident with the adjacent portion of the series of holes b, and indicated in dotted line at e in Fig. 433 ; below it is an outlet .chute f. The lower extremity of the lifter D is slotted, to allr a lever g to pass through it, one end of which lever is pivoted at one side of the frame A, while the other end is curved upward to rest upon a cam m on a shaft H extending along the opposite aide of the frame. The ehaft H bas a spiral dise h at its forward end, which gives an intermittent rotary movement to the carrier plate, insuring the retention of each hole b in succession above the die E and below the die F for a certain definite time. The shaft H gears by bevel wheels n r with a bell-crank abaft J, driven by spur gears s t from a driving shaft K furnished with a pulley u for a driving belt. L is an elbow lever, whose extremity e" is pivoted to the lower part of the sliding head G, and whose free end connects by a pitman w with the crank m of the shaft J. To the bend of this elbow lever, is pivoted tbe bar z, whose upper end is pivoted to the fixed guides A', in such manner that the bar and the part e" of the elbow lever form tngether a toggle joint, capable of giving a vertical movement to the head, from the rotation of the crank ; the down ward stroke of the latter continually increases in power as the toggle joint straightens. M is a bellows whieh, being actuated during the downward stroke of the crank m, by the striking of the etud m" of the elbow lever L upon the arm n" of the bellows, sends a puff of air through its nozzle r" to blow away any dust which may have aceumulated upon or near the dies. The method of operation is as follows :—The buttons are placed singly in the holes b, and by the movement of the carrier plate are brought under the rotating die F. The movement of the carrier being suspended for a moment, the sliding bead G is brought down with great force by the straightening of the toggle joint, the die F on the head G being meanwhile rapidly revolved by the action of the belt on the fast pulley C'. As a consequence, tbe button is eubjected simultaneously to greet pressure and to the frictional contact of the die F upon its upper or outer surface, the force of the die e,orre sponding in contour to the surface of the button. It is thus effectually smoothed and burnished, the colours are brightened, and tbe lines are sharpened without crumbling. This operation con cluded, the continued working of the machine lifts the die F, whereupon the cam m raisee the lever g, while the lifter D forces up the lower die till its top is level with the upper surface of the plate C. Then the action of the cam h on the teeth a turns the carrier plate B, until the bole con taining the button is brought over the slot e, whereupon the button falls into tbe chute f, away from the machine. The same movement of the machine also brings the next bole into proper position with regard to the dies, so that the whole operation is continuous, and the work is per formed with speed and economy.