445 



TURNING. 



TURNING. 



416 



all sizes and proportions with almost the same ease as circles. The 

 construction of the chuck is simple. Upon the front of the head- 

 stock, H,/.,. 17, is placed a ring, held by screws through its two arms 

 and the projecting pieces on each side of the headstock ; a screw is 

 placed in one arm of the ring to draw it out excentrie to the mandril. 

 Fig. 1 8 shows the front of the chuck with a slide moving between dove- 

 tails on a ground-plate ; the ground-plate, as shown in Jig. 19, has two 



Fig. 1 7. 



Fig. 10. 



slits cut from the centre boss, which screws on to the "mandril, nearly 

 to the circumference ; two small studs are cast upon the back of the 

 slide, which are made to work easily in the two slits, and stand up 

 just above the face of the ground-plate. When the slide is in its 

 place two steel rubbers with straight polished faces are screwed to 

 the studs, and stand out at the back of the ground-plate at right 

 angles to the slits, as seen in fy. I 9 - The ring being fixed in its 

 place upon the headstock, the chuck is screwed upon the mandril, 

 the rubbers clasping the ring, which must be kept perfectly smooth 

 and well oiled ; the excentricity of the ring, acting upon the rubbers, 

 draws the slide out of the centre in opposite directions alternately, 

 and upon the tool being applied an oval will be described upon the 

 face of the work, having the shorter diameter in proportion to the 

 distance of the tool from the centre, and the longer to the excentricity 

 of the ring. For ornamental work the oval chuck is provided with a 

 ciiek and sometimes a micrometer plate, like the excentrie chuck, for 

 placing the ovals in different directions. 



M Turning. Of all the different sorts of ornamental 

 turning this is by far the best adapted for embellishing small articles. 

 It is in very general use for gold, silver, and gilt work ; it U besides 

 applied to the production of ground tints, borders, and ornaments on 

 copl:r, steel, and wood rollers for printing and embossing calico, 

 leather, and paper ; and many other wirts of ornamental work. An 

 unsteady lathe, which in revolving produces an irregular circle, is a 

 rude approach to the rose-engine, and may very possibly have furnished 

 the first hint for its invention. We shall now describe it. H (jvj. 20) 



Fig. 20ri. 



is a headstock, supported upon the conical points of two screws, c c, in 

 the two metal standards, A A, fitted and Ixilted to the bench or bed. 

 In the front and buck of the headstock, near the bottom, are two sunk 

 centres to receive the conical points of the screws. The screws are 

 secured by washers that run upon them, and tighten against the 

 standards. The upper part of each standard carries two other screws 

 r.t right angles to those described, for the purpose of holding the head- 

 stock steady when the rose-engine is to be used as a common lathe. 

 Two of these screws are shown in the frout of the engine (fy. 21). 

 Upon the mandril are mounted the pattern guides, or rosettes, circular 

 plates of gun-metal or bras 3 , each about half an inch thick, and having 

 two patterns or waves upon its rim. The rosettes are of two sorto, 

 fixed and shifting. The fixed, F, are screwed to a collar turned upon 

 the mandril itself ; the moveable, it, are fixed upon a cannon, B (./?</.20) ; 

 the plate II is fixed to the cannon, and the rosettes are prevented from 

 turning by a feather which fits into a notch in each of the rosettes : a 

 nut at the end of the cannon screws all tight against the plate M. The 

 plate D is put on the mandril at the back of the cannon plate M, but 

 independent ' f both; behind this is another plate, P, fitted on to the 

 mandril, and turning with it ; at the back of this plate is a nut, which 

 is tightened until the cannon requires some little force to turn it upon 

 the mandril with the hand. On the large plate P, is a spring-click, 

 which falls into notches cut in the platv I), which itself carries an end- 

 lea screw working into a half thread cut on the edge of the cannon 

 M. T is a carriage for holding the rubber K, by means of the two 

 crews in the top of the carriage : the rubber is a small bar of steel, 

 three or four inches long, and the breadth of the rosettes. Screwed 



into the bottom of the headstock is a strong arm, h (fig. 21), with 

 a square hole near the bottom, to receive a smaller arm pierced with 



fig. 21. 



R cd-:r 



holes ; one end of this latter is attached to a strong spring, s, and by 

 placing a pin in one or other of the holes in the small arm, the spring 

 may be made either to press or pull the arm h with less or greater 

 force. The rubber-carriage T being moved along the bar B till the end 

 of the rubber is exactly opposite the face of the rosette to be employed, 

 and fixed there by the back-screw, the spring set to pull the arm h, and 

 the side screws in the standards A turned back until the face of the 

 rosette rests upon the rubber R, the engine at each revolution will pro- 

 duce a copy of the indentations upon the face of the rosette The 

 engine is moved by a hand-winch with a band passing round a foot- 

 wheel, and another connecting a small pulley on the crank with the 

 mandril-pulley B, in the same manner as the slow motion of the foot- 

 lathe (Jig. 2). The slide-rest is adapted to the rose engine in the fol- 

 lowing way. The tail-piece of the rest F (fys. 20, 22) has a hollow 



Fig. 23. 



Fir. 24. 



cylinder, c, fixed in the middle of one end. The bar B, which has a 

 piece at each end fitting into dovetails in the sides of A, has a cylindri- 

 cal piece which fits accurately into the hollow cylinder c, and can be 

 raised or lowered at pleasure by a ring or nut, N, working upon the 

 outside of c, the rest being placed in the required position, and fixed 

 to the bench by the screw s (/</. 2;i). The stock A moves round upon 

 the cylinder c, and can be fixed at any required angle by the binding 

 nut o. The top of the re.st, which traverses along the bar B, by means 

 of a screw throughout its length, provided with an index-plate and 

 winch-handle, s, is composed of two parts, the ground plate (////. :.':') 

 and another plate (fig. 24), which carries the tool-slide. The engine is 

 also capable of turning the sides and edges of work, for which purpose 

 it is provided with a separate set of waves cut upon the sides of the 

 rosettes, some of which are made of larger diameter than others for 

 that purpose. The rubbers are shaped at the side to correspond ; the 

 mandril has an eudway -motion within its bearings, and is acted upon 

 in either direction by the lever-spring o (fy. 20), which has its fulcrum 

 upon the bench : its upper end is forked, and fits a groove in the 

 mandril, and the lower held by an arm and pin. For side-work the 

 slide-rest is placed parallel with the bench as in common turning. 



The square, or slraii/kt-Hnr. chuck, is peculiar to the rose-engine, and 

 forms a very material part of it ; the object of it ' s * ' a 7 ^ e patterns 

 in a straight instead of a circular direction. Fig. 25 represents the 

 straight-line chuck ; the square frame, A A, is fastened to the two arn:s 

 of the headstock, shown in fy. 21, by bolts and nuts, or wedges; 

 B, B, is a slide connected with the nose of the mandril either by a chain 



