Lathe design, construction and operation with practical examples of lathe work

The aim of the Author in writing this book has been to present in as comprehensive a manner as may be within the limits of a single volume the history and development of the lathe from early times to the present day; to briefly discuss its effects upon manufacturing interests; to describe its practical use on various classes of work; and to compare in a representative, theoretical, and practical manner the Modern American Lathes as now built in this country.

In carrying out these aims the early history of the lathe is traced from its crude beginning up to the time when the foot power lathe was the sole reliance of the early mechanic. Then the early history of the development of the screw-cutting or engine lathe is taken up and carried on to the middle of the last century. This is done to put the student and the younger mechanic in possession of the facts in relation to the origin and development of the lathe up to within the memory of many of the older mechanics of the present day.

The matter relating to the early history of the lathe is introduced for what seem to be good and sufficient reasons. If we are always to “commence where our predecessors left off” we shall miss much valuable information that would be very useful to us. A retrospective glance on what has been, a review of previous efforts, a proper consideration of the road by which we came, or by which earlier workers have advanced, is not only interesting but necessary to a full and complete understanding of the subject, and very useful to us in mapping out the course for our continued advancement in contributing our share in the development of mechanical science.

Following along these lines, the various types of lathes have been carefully classified, engravings and descriptions of the prominent American lathes are given, and their special features of design, construction, and use are pointed out and briefly commented upon.

It is a matter of much pride to every true American mechanic that this country produces so many really good and meritorious manufacturing machines, and in no line is this superiority more clearly shown than in the magnificent array of Modern Lathes. This work brings these machines together in a comprehensive manner for the first time, and thus aims to add its quota to the present literature on this subject, and so make it valuable as a book of reference, alike to the student, the designer and the mechanic, as well as the manufacturer and the purchaser of Modem American Lathes.

In the revised and enlarged edition of this work a chapter has been added detailing all kinds of lathe work, treating of lathe installation and management, milling, drilling and grinding attachments and their use, methods of turning tapers, turning spherical surfaces, making oil grooves and many other processes pertaining to practical lathe work. Endeavor has been made to have this information sufficiently clear so it may be readily followed by the apprentice, student or amateur machinist.

The essential elements of a lathe. The bed. The head-stock. The tail-stock. The carriage. The apron. The turning and supporting rests. The countershaft Taper attachments. Change-gears. Classification applied to materials, labor accounts, and the handling of parts in the manufacture of lathes. The four general classes of lathes. The eighteen sub-divisions of these classes. The first class: hand lathes, polishing lathes, pattern lathes, spinning lathes and chucking lathes. The second class: engine lathes without thread-cutting mechanism. Fox brass lathes, forge lathes, and roughing lathes. The third class: complete engine lathes with thread-cutting mechanism, precision lathes, rapid reduction lathes, and gap lathes. The fourth class: forming lathes, pulley lathes, shafting lathes, turret lathes and multiple spindle lathes. Rapid change gear devices. Bancroft and Sellers device. The Norton device. Lathe bed supports. The precision lathe. The rapid production lathe. The gap lathe. Special lathes. Forming lathes. Pulley lathes. Shafting lathes. Turret lathes. Screw machines. Multiple spindle lathes. Variety of special lathes.

In considering what are the essential elements of a lathe they may be briefly stated, if we assume that in a simple lathe the work is to be what was originally intended, that is, held on centers, and may be stated in these terms, viz. The essential elements of a simple metal turning lathe are : suitable means for supporting and holding the work upon centers; proper mechanism for rotating the work; and a cutting-tool properly held and supported upon a traveling device actuated by suitable mechanism.

The first of these essentials comprise the bed, head-stock, and tail-stock, with their proper parts and appendages, so far as the fixed parts and centers are concerned, and including legs or other supports for the bed. The second essential comprises the driving mechanism, consisting of the driving-cone, back gearing, etc., and the third essential consisting of the carriage, tool block, and cutting-tool, with the necessary gearing for moving it, and the connecting parts for transmitting power for that purpose from the main spindle of the lathe.

This classification of the essential elements of the lathe naturally suggests certain groups of related parts which compose a complete lathe, and correspond with the experience and practice of the author in the designing and construction of the various types of lathes. They are as follows:

1. Bed and appendages, including the legs or cabinets, lead-screw and its boxes, the feed-rod, its boxes and supports, carriage rack, tail-stock, moving rack (when the lathe is large enough to require one), stud-plate and studs, and such necessary bolt and screws as are needed to fasten these parts.

2. Head-stock and appendages, including such feed-gears as are necessary to connect with the feed-rod in case of a geared feed. Also the holding-down bolts and binders (if used), for fastening the head-stock to the bed, and the large and small face-plates. (Where a quick change gear device is used and is not an integral part of the bed or head it forms a separate class.)

3. Tail-stock and appendages, such as holding-down bolts, binders, and, when the lathe is large enough to require it, the mover bracket, gears, shafts and crank ; and if the tail-spindle is handled by a hand-wheel in front, the brackets, shafts, spur and bevel gears, etc.

4. Carriage and appendages, including gibs and a solid tool block if one is used, but not a compound rest where' these are furnished at the order of the purchaser. If the lathes are habitually built with compound rests they may be classed with the carriage.

5. Apron and appendages, including the apron in its complete assembled form ready to attach to the carriage, together with the screws for making such attachment.

6. Rests, including the compound rest (when not classed with the carriage, the full swing, pulley or wing rest (as it is variously named), center rest, back rest, (when one is furnished), together with bolts, binders, and similar means of attachment.

7. Countershaft and its appendages, including the hangers, boxes, shipper rod, etc., and any similar parts for tight and loose pulleys or friction pulleys as may be necessary to make it complete and ready to put up.

Taper attachments, special tool holders, or tool-rests, and all similar parts are deemed extras and not included in regular lists.

Change-gears are sometimes listed as a part of the bed and appendages. When these are a part of a special quick change device they are made a separate class. This is understood to be when the change gear device is detachable. When made a part of the head-stock or the bed such parts as are attached to the one or the other of these main parts will be listed with it and become a portion of its appendages.

This classification is carried into all lists of materials of whatever kind and into all accounts of labor in the designing, constructing, and handling of these parts, whether in groups or as single pieces, during then- progress through the various departments of the shop.

The classification of these lathes as entire and complete machines, and according to their various types of design and construction and the uses to which they are to be put, will be next considered, and in so doing it seems appropriate to commence with the more simple forms, and to proceed with such types as are commonly recognized and in use at the present time, dividing them into four general classes and these into such sub-divisions as their construction and uses seem to demand By this method of classification we shall have:

In the first class we understand by speed lathes a lathe without back gears and without the carriage and apron of an engine lathe, although as chucking lathes they may be provided with back gears, as they are frequently used for boring quite large holes, and are therefore made much larger and heavier than those of the other sub-divisions of this class.

Hand lathes are supposed to be for the usual operations of hand tool turning, filling and light metal turning by means of a detachable slide-rest. They may have legs of sufficient height to support them from the floor as in Fig. 16, or with very short legs, making them convenient for setting upon the usual machinists bench as in Fig. 17. Otherwise their design and construction is the same.

Polishing lathes are, as their name implies, mostly used for polishing cylindrical work, although a hand-rest or a slide-rest is sometimes used upon them.

Pattern lathes, as shown in Fig. IS, are usually so called when used by wood pattern-makers and while usually used with hand tools, as chisels and gouges with the support of a hand-rest, at the present time a majority of them are provided with a slide-rest. Those of larger swing have the rear end of the main spindle threaded for attaching a face-plate upon which is fixed large face-plate work of too great a diameter to be turned on the ordinary face-plate, as this supplemental face-plate overhangs the end of the bed and consequently the diameter of the work that can be turned is only limited by the height of the main spindle above the floor. In this class of work a hand-rest is supported by a tripod stand that may be moved to any desired position on the floor and is heavy enough to stand steadily wherever it may be placed.

Spinning lathes are used for forming a great variety of shapes from discs of quite thin metal, usually brass, with various shaped tools held either by hand or in the tool post of a slide-rest. These tools form the metal in a manner similar to the action of a burnisher instead of cutting it, usually over a former, by which the same shape is produced in all the pieces. Such work is not usually of large diameter, therefore a spinning lathe is generally of small and medium swing and is of substantially the same construction as the ordinary hand lathe, except when built for large or special work.

Chucking lathes, shown in Fig. 19, are used to a great extent for boring and reaming circular castings, as pulleys, gears, hand- wheels, balance-wheels, sleeves, bushings, flanges, and all similar work that require only the formation of the hole, although some of these machines are provided with a cross-slide and tool-post by means of which the hubs or bosses of the work may be faced. Many of them are now provided with a turret, by means of which several tools may be carried so that not only boring and reaming, but recessing, facing, etc., may also be done without removing the work from the chuck. These lathes usually have a very large driving-cone with a broad belt surface, or they are constructed with back gears similar to those in an engine lathe. It was from this form of lathe that the elaborate lathes built by Jones & Lam- son and others of similar design and construction originated.


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Lathe design, construction and operation with practical examples of lathe work