New Form of Rose Engine by E. Taylor
Seeing that the Editor of the above Articles has illustrated and described Holtzapffel and Co.’s Rose Cutter and two methods of executing rose cutting, the latter being the ordinary rose engine, I am induced to send you a description of a method that I have adopted whereby I can with considerable despatch execute this description of turning.
I will first preface my description by saying some thirty years ago I purchased Ibbetson’s Book on eccentric turning, and I was so much taken with it and the illustrations, that I determined to make myself in accordance with his description and engravings an eccentric chuck; and although I was a long time about it, being at the time much otherwise engaged, I succeeded beyond my expectations, and was enabled to do some very fine work with it; and I have never regretted the time I spent over the chuck, as I became familiar with metal turning and screw cutting flying in the lathe, which latter I was surprised to find how easily I could execute. However, I was much disappointed in the usefulness of the chuck (Holtzapffel’s eccentric cutter, which I purchased is far more useful), and also with the tediousness of using it (fancy stopping the lathe to alter the chuck 360 times or 180 times to cut a row of circles either distinct or overlaying each other), and there was also a certain vibration occasioned in using the chuck which I also disliked. I therefore determined to cut up some rosettes and convert my headstock into a rose engine, to effect which object I got Holtzapffel and Co. to return up with a new steel collar and make my mandrel traversing. I cut myself a rosette both ways with 16 waves, and I was much pleased with the variety of work I could perform with this one, but the rosette took me a long time to make, and disheartened me from cutting up a variety. It, however, occurred to me that if I added an extra mandrel by the side of and attached to my headstock, and on which extra mandrel, if I had an eccentric chuck connected with a rod to the wall of my room, I could get my headstock to oscillate, and by connecting and multiplying wheels cause as many waves on each revolution of my principal mandrel I pleased; this after much time and patience I succeeded in doing, and worked it with the hand motion often adopted for rose work. After between two and three years, I put the extra mandrel over my principal mandrel instead of by the side as before, to enable me to dispense with the hand motion and to work the upper mandrel with the slow motion on my lathe wheel, and which I found a very great improvement, and I now give the details of the plan I have adopted for the benefit of your numerous readers.
The drawings are to a two-inch scale, or one sixth of their full size.
Fig. 400 is a side view of my headstock (part in section) with the upper mandrel, A, added, showing the connection by an intermediate spindle, B, with the large cog wheel, C, on my lower mandrel, D, and other additions.
The back centre, E, of my headstock is connected with the back screw, F, and drawn out or pushed in with it, and is fixed by the set screw, G. When drawn out the steel screw, H, at the end of the mandrel, D, removes to receive the screw guides which are then fastened by it, and the piece, I, with segments of a thread to match the guides, is slid up by a wedge to the guides and then fastened by the screw J, I, can also fix some roses cut on the side, and other apparatus with this screw H.27
The large cog wheel, C, is screwed up with the screw, K, to the mandrel pulley, L. On the front of the pulley is the division plate as usual.
The intermediate adjustable spindle, B, is carried in a frame shown separately by Fig. 405; it is allowed to rise or fall as may be required for the wheel, M, to gear with the great wheel, C; provision being also made for an intermediate wheel, N, (see Fig. 403) to connect the wheel, O, with the wheel, P, on the upper mandrel when required.
The eccentric chuck is fixed on screw Q of the upper mandrel.
Fig. 401 is a plan of the mould for the back cast-iron upright, fixed to the headstock with screws at the foot, showing the circular grooves 1, 2 and 3, necessary for the spindles for the connecting wheels; the centre hole, 4, is for the gun-metal collar, or the upper mandrel.
Fig. 402, is a plan of the mould for the front cast-iron upright; the centre holes 1 and 2 are for the collars of the mandrels. No. 2 is made to just fit over the steel collar of the lower mandrel, and is fixed to the headstock by a brass rose and three screws; it is also fixed at the foot with two screws to the headstock.
These two castings, 401 and 402, are bolted together with two bolts and nuts through the holes 5 and 6, as shown in Fig. 400. Fig. 403, is a back view of the additions, showing the cog wheels and their connections, also the brass bearings for the lower mandrel required when allowed to traverse. This was a solid piece of brass with a hole bored out and ground to fit the mandrel. It was then drilled the whole depth in two places, for two steel steady pins, b, c, made to fit quite tight, and at both ends for bolts and nuts, a, d, afterwards sawn in two with the circular saw, and when put together and two holes drilled through the thickness for fixing it was put in its place, adjusted, and re-ground on. The holes for fixing were very carefully continued through the cast iron upright, and the whole was finally fixed with two screw bolts and nuts.
Fig. 404, is a front view, showing the eccentric chuck, R, on the upper mandrel, the slide of which when used is connected with the bracket in the wall, Fig. 406, causing the whole apparatus to oscillate in proportion to the eccentricity of the chuck on its centres one of which is marked at S. The chuck has a circular movement for laying the waves in any position with one another, but which also is effected by another plan to be presently described. The whole poppet with its fittings is hung on centres similar to the rose engine described in this work. The top part of the bed T removes, and the two screws, one shown at V, are taken out to allow the oscillation. The large cog wheel has 192 teeth.
The whole of the additions to my headstock were all of my own fitting up. The brass cog wheels were bored out and ground to fit an arbor made on purpose, exactly corresponding in diameter with the ends of the spindles so that they might fit indiscriminately on either spindle. When turned up, the teeth were cut with a circular cutter, which I made just of the exact shape and thickness required for the space between the teeth. The cutter was turned of steel; then wrapped in leather and enclosed in sheet iron. It was then put in the fire, made red hot, and left for the fire to go out, the next day being soft, it was cut with sharp chisels into a circular file and hardened, and with it in the cutter frame the teeth of the wheels were cut. The central boss of each wheel has a notch cut across the face to receive a pin in the arbor and in the spindles, which prevents the wheels from turning round on the latter when screwed up.
This rose engine works beautifully smooth and easy, and ornamentation can be done with it with greater rapidity than with the ordinary engine, by arranging the connecting wheels so that the upper mandrel makes so many waves and one-half, one-third, one-fourth, one-fifth, one-sixth, or any other part of a wave, on each revolution of the lower mandrel, because then it requires certain revolutions of the lower mandrel before the tool comes into the same cut again—say, for instance, it makes 45/6 waves on each revolution, then it takes 29 revolutions of the upper mandrel to complete the pattern, whereby certain patterns are completed without stopping the lathe, which is an advantage that the rose engine proper does not possess. Another great advantage is, that the waves can be either flat, sharp, or intermediate, as required for large or small work, by altering the eccentric chuck on the upper mandrel.
I give a few specimens, not for the beauty of design, but to illustrate the working of the engine. The centre of Fig. 407 is performed by having a wheel of 80 teeth on the upper mandrel, connected with one of 25 teeth on the intermediate spindle, which has another of 50 teeth connected with the large wheel of 192 teeth on the lower mandrel; thus,
| 80 | ||
| 25 | 50 | =11/5 |
| 190 |
producing on each revolution of the lower mandrel one wave, and one-fifth of another wave, requiring six revolutions to complete the pattern.
The remainder of the pattern is completed by wheels, 16, 50; 48, 192 making 12½ waves on each revolution of the lower mandrel, requiring 25 waves to complete the pattern, and laying the waves over each other, and with the slide rest movement of the tool.
Fig. 408 is produced by wheels 32, 48; 24, 192 making 12 waves. The centre is done by altering the eccentric chuck each time. It was purposely executed askew, by the tool not being placed in the centre, to show the importance of doing so for some patterns. The rim was executed with the same wheels, and with the slide rest movement of the tool, and, after two cuts, the chuck turned half round, to lay the waves over each other for the other two cuts.
Fig. 409 is all executed with wheels 96, 30; 25, 192 making two waves and two-fifths of another wave, requiring 12 waves to complete the pattern. The two centre rims produced by placing the tool above the centre. The outside by four movements of the slide rest tool, illustrating how soon patterns are produced, and when well cut up look very pretty.
Fig. 410 is executed with wheels 80, 50; 25, 192 making four waves and four-fifths of another wave, requiring 24 waves to complete the pattern. The centre is all done without stopping; the outside rim by altering the eccentric chuck four times, to make each successive wave flatter.
Fig. 411 is an illustration of the upper mandrel, making 5⅓ revolutions to one of the lathe, requiring 16 revolutions to complete the pattern and slide-rest movement.
Fig. 412. The outer pattern of this figure is produced by the upper mandrel making 12⅘ revolutions to one of the lathe, requiring 64 revolutions to complete the pattern. The centre is a rosette of 5 waves, slide-rest movement and placed across each other.
Fig. 413. The whole of this pattern produced by the upper mandrel making 3⅗ revolutions to one of the lathe, producing 18 waves across each other with slide-rest movement for the middle rim.
Fig. 414 illustrates a rosette of nine waves with slide-rest movement, and 3 divisions of the circular movement of the eccentric chuck for each successive line, producing the waved appearance.
Fig. 415 illustrates a rosette of 24 waves with the slide-rest movement.
Fig. 416. Another illustration of a rosette of 24 waves, rather more sharp than in Fig. 415, with slide-rest movement and 9 divisions of the circular movement of the eccentric chuck, giving it a pleasing circular waved appearance.
Fig. 417. Also another illustration as the last, but with the waves much sharper, the slide-rest movement and only two divisions of the circular movement of the eccentric chuck producing the star-like pattern.
Fig. 418 illustrates also a rosette of 24 waves, with the eccentric chuck turned half-way round with each movement of the slide-rest, producing the pattern so often seen on the back of watches, only being on wood it is on a larger scale.
The above illustrations are sufficient to give a distinct idea of the working of my engine, and the last four show how easily patterns are multiplied and varied.
The whole of the preceding patterns were executed by the wood being chucked in the lathe in the usual ordinary way without any particular chuck whatever, but in combination with any of the ornamental chucks innumerable patterns can be produced.
Fig. 419 is one illustration with an eccentric chuck on the lathe mandrel.
That my description may be complete I will now give drawings of my eccentric chuck for the upper mandrel. It requires to be constructed differently to the ordinary eccentric chuck, as the circular movement requires to be always central, and only the slide carrying the pin to receive the rod must move eccentrically.
Figs. 420 and 421, are full-size drawings of my eccentric chuck on my upper mandrel, used for producing the foregoing specimens. In this case I have preferred a wood foundation, as not being so likely to run off as metal, on reversing the motion which is sometimes necessary on account of idle wheels for the connections. I used a piece of well-seasoned Spanish mahogany, taking care that the grain of the wood was at right angles with the length of the screw of the mandrel. A piece of brass is screwed at the back to prevent the screw cutting into the wood. Fig. 420 is a section, and Fig. 421 a front view of the chuck, and I think all sufficiently clear. I will just say the long fine threaded screw I cut up with the stocks and dies in the lathe, using steel wire of the necessary size. This I manage easily, and keep the wire straight by allowing it to expand in length. I chuck the steel wire concentrically, and removing the centre from the back poppet, substitute a brass centre with a hole the size of the steel wire, which is allowed about a quarter of an inch entry. I then turn down a little below the depth of the intended screw thread for about half an inch in length next the back centre, to allow the dies to come back to be tightened up, and which must only be done at the commencement and not on the return motion of the dies. The collar on the screw is a piece of brass with a hole of a size to drive on the wire tight, and is then pinned on and turned up true, and finished with the division marks.
Notes
27 It is not a good plan to make the point, E, movable. It would be better to slip the guides or rosettes over it: and generally to arrange this part as usual with a traversing mandrel, P, H.