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Read Ebook: The Standard Electrical Dictionary A Popular Dictionary of Words and Terms Used in the Practice of Electrical Engineering by Sloane T O Conor Thomas O Conor
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Ebook has 115 lines and 30385 words, and 3 pages
PREFACE.
Introduction.
Chucks.
Hand Turning of Wood.
Hollowed Work.
Cutting Screws.
Hollowing Out Soft Wood.
American Scroll Chuck.
Metal Turning by Hand Tools.
Overhead Apparatus.
Self-acting and Screw-cutting Lathes.
Wheel Cutting in the Lathe.
Fret Saws to Mount upon the Lathe Bed.
Turning Spheres.
Hoblyn's Compound Slide-Rest.
Chucks with Slides and Compound Movements.
Turning Ovals, etc., by Means of a Template.
Eccentric Chuck.
Curiosities.
Grooving and Mortising Small Work.
Ornamental Turning.
The Eccentric Cutter Frame.
Segment Engine.
Holtzapffel's Rose Cutter Frame.
Universal Cutter Frame.
Rose Engine.
Rectilineal Chuck.
Epicycloidal Chuck.
The Spiral Chuck.
Professor Willis's Tool Holder for the Slide Rest.
Munro's Planing Machine to be attached to the Lathe, and worked with the foot.
Hicks' Expanding Mandrel.
Turning Spheres by means of Templates.
Plant's Geometric Chuck.
A Paper on the Principles which Govern the Formation and Application of Acute Edges, with special reference to Fixed Turning-tools, contributed by Mr. Dodsworth Haydon.
Detached-cutter Holders.
New form of Rose Engine by E. Taylor.
Oval Turning and Rose Cutting with Templates with my Apparatus.
THE LATHE AND ITS USES.
The Lathe has now for many years been steadily making its way from the workshops of our leading artisans to those of the amateur and lesser stars of the mechanical world. This is but the natural result of the various additions and improvements which have been introduced into its construction from time to time. The unworkmanlike and clumsy tool of olden days has long since been superseded by one of admirable finish and perfect aptitude for its designed uses; and now that its construction is no longer dependent upon the skill of the workman alone, but upon machinery moving with the precision of clockwork, the fitting of the various parts is accomplished with the greatest ease and certainty. The sale being thus extended, the price has considerably diminished--the monopoly enjoyed by one or two makers no longer exists; and there are few of a mechanical turn of mind who cannot now provide themselves with a lathe suited to their requirements.
Nevertheless, the adepts in the art of turning are by no means so numerous as might be expected, and, among amateurs especially, it is rare to find work executed in first-rate style by simple hand tools requiring skill and practice in their use, so that it not unfrequently happens that a workman who can turn out exquisite specimens of ivory carving and ornamental lathe work, is but a fourth-rate hand with the gouge and chisel.
Moreover the one requires lathe fittings, which are not always to be had unless the purse is well filled, whereas the general mechanic can provide the tools needed for the other; hence we propose first of all to give some practical hints on plain hand turning of wood and metal. The ordinary form of foot lathe is well known and requires no special description, it is represented in the frontispiece of this volume. There are, however, certain points of detail in its construction, to which it is necessary to direct the reader's attention.
First and foremost comes the mandrel, of which there are several patterns, according to the special purpose for which the lathe may be intended.
Now of whatever form it may be made this is the essential part of the lathe, and must run with the utmost truth in its bearings. Imperfection here will be imparted to all work executed upon it, and accuracy in this part alone will make up for any slight defects that may occur in less important parts of the machine.
For ordinary work in wood alone or in brass the best form is represented in Fig. 1.
It will be found of great convenience to have the screw on the nose of the mandrel of standard Whit worth pitch, as taps for the chucks are thus readily obtained, and nuts and screws of the various sizes may be also procured to remedy breakages and losses. Upon this subject, however, we shall have occasion to treat more fully when we pass from the description of the lathe itself to the work that is to be accomplished by its aid.
It is evident that by turning the wheel the internal screw is put in revolution, and as it is prevented by its flange from assuming any motion in the direction of its length, the movable cylinder will instead be withdrawn or thrust forward.
Another useful adjunct to the lathe is the back rest for supporting long and slender articles, which would otherwise bend under the pressure of the tool. The ordinary and simplest form is shown in Fig. 15, and this is of general use with brush handle makers and others whose work is confined to a few sizes and shapes only. A better form is shown in Fig. 16. A support of wood or metal shaped like A is clamped to the lathe bed. Through the upper part the slide B passes and is wedged up so as to support the work--or the socket of a lathe rest may be arranged to take the upright part A, which must then be rounded, as shown at C.
There is a plan practised by German turners by which the back rest is in a measure superseded, and which may be mentioned here. It is simply the peculiar method of using the left hand. This is placed on the piece to be turned so that the fingers partly encircle the work while the thumb rests in the hollow of the gouge, or upon the end of the tool. The fingers thus form a back rest and keep the work pressed against the cutting edge, which is further steadied by the thumb. As the tool traverses the work the left-hand accompanies it, and with a little practice a ramrod or similar long and slender article may be readily and accurately turned. This position is shown in Fig. 17, and though the novice will find it difficult to work thus, it is well worth the trouble of mastering, as the method once acquired will be found of very great service.
We have now described more or less in detail the principal parts of the lathe as adapted for hand turning. Before we dismiss this part of the subject, however, it will be necessary to say a few words respecting the bed and lower fittings, the flywheel, treadle, and their adjuncts.
They must then be screwed down firmly, and by means of a file worked by both hands up and down their length a good surface may be readily obtained. If the iron is let into the bed this filing will abrade the wood work, which is the reason why we prefer screwing it on the surface. This method produces a very excellent and durable lathe bed, and it will be free from much of the tremor which is so disagreeable while working upon a lathe entirely of cast iron unless the bed of the latter and the standards are more substantial than is usual with small lathes.
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