The watchmakers' lathe, its use and abuse; a story of the lathe in its various forms, past and present, its construction and proper uses

Introduction

The American lathe and its attachments is a subject so vast that anything like a complete work upon it would be sufficient material for a book larger by far, perhaps, than any workman not thoroughly acquainted with the subject would deem possible. In point of accuracy, variety of work, and ease and convenience of manipulation, the American watchmakers' lathe, with its several attachments, stands supreme ; any piece of work, however delicate and intricate, may be executed upon it by an accomplished workman. But let us recall the various stages through which the lathe has passed before arriving at its present state of perfection, in order that those of to-day may the better appreciate the accuracy and convenience of the modern watchmakers' lathe, which stands alone in design and construction of this class of machinery, as it is the only one which has been evolved from the brains of skilled engineers, familiar with all the demands of automatic machinery, and who, having the whole range of modern mechanical attainments at their fingers' ends have devised a simple and effective machine which the skill and ingenuity of the American mechanic have made possible for any watchmaker, even of limited means, to possess.

The present state of perfection in watches is dependent, to a very great extent, upon the accuracy of the tools produring them, the most important one being the lathe, in its various forms, not only because of the comparative ease and rapidity of performance, but also from the wide range of work and variety of operations which may be performed upon it. An American watchmakers' lathe, with a complete set of attachments, such as may be bought of the various manufacturers, is capable of producing a complete and perfect watch of the highest order, when manipulated by a skillful hand. »

From an artistic point of view, many of the watches made by "the old masters" are most meritorious and worthy, when we consider the means at their command ; but as timekeeepers they would to-day be pronounced complete failures, and while the work of these men, from a mechanical point, is all that could be expected of them at that time, yet their rude work, and still more rude tools, if applied to the fine watches of to-day, would be their death knell.

In some localities, even now, the natural born watchmaker who can tinker a watch or clock "so it will go" is looked upon as a mechanical prodigy. The day of those watches which kept time with the sun is past and gone, never more to return. The modern business man demands a timepiece approaching very closely tcv perfection, and such fine and delicate machines in turn require for their repair tools of the highest possible accuracy and a skillful hand, such as is only acquired by long and tedious practice. Some workmen seem to think that all that is necessary to do good work is to get a set of tools, however cheap, and consequently worthless. There are very few persons who have achieved success except by persistent labor and study of their chosen vocation.

In mechanics, as in all else, there is no such thing as perfection, and the highest that man can attain with his best efforts is to approach the ideal perfection as closely as possible.

While the modern American watchmakers' lathe and its attachments will produce accurate work with more ease and certainty than can be done by the tools generally prevalent in Europe, they cannot be used carelessly, but must be guided by a trained mind and skilled hand, and it is our desire to so explain these tools, their capabilities and the limitations to which they are subject, that the young man who enters the trade to-day may understand fully, what he may with justice require of his tools, and also what, in their turn, his tools will require of him, in order that they may receive that intelligent treatment, which is indispensable to their accuracy and length of life.

In order to understand fully the immense improvements to be found in common use to-day, let us glance at the origin and successive forms of this useful tool during the centuries it has been in use.

Chapter I. A Brief History Of The Lathe

The lathe dates long before the Christian- era, and in one of its forms, the potters' lathe, is mentioned in the Bible. A well-known authority has stated that what he called the "prehistoric lathe" is undoubtedly the earliest type, but we are inclined to believe that the true home of the lathe is Egypt, and that the lathe used in that country

Fig. 1. Prehistoric Lathe.

and some parts of the far east to-day is not very dissimilar to those used before the advent of the Christian era. The so-called "prehistoric lathe" is illustrated very clearly in Fig. i. It will be observed that the bearings consist of the forks of the two trees, and that the tool-rest consists of a sapling driven into the ground. The piece to be turned is revolved by means of a crank fastened to one end.

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Fig. 2 illustrates what is known as the Egyptian lathe, and the form, modified slightly in various cases, is used extensively throughout Egypt and the Asiatic countries to-day. The lathe shown in the illustration seems capable of turning work within certain limits only, and is not adjustable; but the regular type is so made as to admit work of any length and any diameter. In the illustration it will be seen that the workman revolves the work by means of a bow with one hand, while with the other he holds the chisel

Fig. 2. Egyptian Lathe.

or cutting device, and his toes are used as a tool rest. In other varieties the turner drives two posts into- the ground, the proper distance apart, to receive the work, and the slot, being deeper, and a number of holes being provided for the reception of the stay-pins, articles of various lengths and diameters may be readily substituted. In India the turner carries his apparatus from house to house or place to place, and when his services are required he drives his uprights into the ground and is instantly ready for business. As a rule he does not use a bow, but wraps a cord around the work, and the boy who usually accompanies him takes io

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one end of the cord in his right hand and the other in his left, and, by alternately pulling on the rope with each hand, he gives the piece the desired motion.

It will be observed that in the prehistoric lathe a continuous motion could be given to the work,, while in the

Fig. 3. Early English Eathe.

Egyptian pattern the motion is reciprocating or oscillating in its character.

Fig. 3 illustrates a later or more advanced type, with reciprocating motion. The pressure of the foot in the stirrup produces a forward motion of the head stock of the lathe, and when the pressure is released the spring of the bent wood causes the head to revolve in the opposite

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direction. Crude as this lathe may appear, it may still be found in use, or at least could a few years ago, in some places in England. A certain case-maker in England has still several such lathes on his premises. The proprietor being asked why he did not equip the lathes with steam-power, which he had in his shop, replied : "These good fellows would not then know how to use them; their grandfathers and fathers before them worked on this kind of lathe, and to try and change them would only result in loss to us."

The watchmaker's bow-lathe is exactly the same as the last two types mentioned, the only difference being in size. We are acquainted with several watchmakers, fine workmen, who still cling to the bow-lathe when they wish to do an exceptionally fine piece of work. They have, and understand pretty well, the use of the modern lathe, but such is the force of early education that they still believe that when accurate work is to be done the bow-lathe is the only thing to do it on.

It seems strange that, with all the boasted progress made in the nineteenth century, there should be still left among us people, and even nations, that, so far as modern tools and appliances are concerned, seem to still belong to the eighteenth and even the seventeenth centuries — people who, through prejudice or want of education, or something inexplicable, still prefer to use the turns or implements of a like nature rather than the modern American lathe for watchmakers, with its substantial base, its live spindle and its excellent slide-rest and adjuncts.

When we say this we do not wish to be construed as criticising the workmanship on the part of watchmakers of other nations, nor do we mean to say that the average American watchmaker is the superior or even the peer

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oi the European. We have our full share of botches. We admire the workmanship of the European watchmaker, which, as a rule, is excellent, but we only regret that the men who have so much inherent genius should continue to employ methods so out of all keeping with their evident talents and skill.

The earliest form of lathe used by the watchmaking fraternity was undoubtedly what is known as the dead-

Fig. 4. Fiddlc-Bow Lathe.

center. These lathes are known as "fiddle-bow lathes," because motion was imparted to them by means of a bowmade of steel, wood, whalebone or other substances, and having a cord of catgut string, and they resembled the bow used by performers on the fiddle or violin.

Fig. 4 illustrates a watchmaker of the eighteenth century at work upon a lathe of this type. It is a portrait of A. L. Perelet, a noted French watchmaker, working at the bench at the advanced age of ninety-three years. In the dead-

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r 3 center lathe the object to be operated upon was held between two male or female centers which did not revolve, and were known as dead centers. While the dead-center type of lathe is not to be compared with the live spindle in point of utility, yet it possessed, no matter how poorly made, one vital point which many modern live spindle lathes do not possess — the element of truth ; and unless the operator was a bungler, this point could never be eliminated. As stated above, this form of lathe still has its admirers

Fig. 5. Steel Turns.

among artisans who readily recognize the great capacity of the American lathe for the greater part of all watch repairing. With all its good points in regard to truth, the dead spindle lathe was relegated to the background in America when the live-spindle form made its appearance, for it was only possible to perform operations upon the surface of objects held in it; and again, the object had, under all conditions, to be first centered before the work began, and here half the true value of the lathe was lost owing to the great loss of time in this preliminary operation. It was impossible, except in a few cases, to work upon the inside of an article, and when the live spindle made its appearance the American watchmaker readily recognized its superiority in this regard.

The verge lathe, the turns, the Jacot tool, and the centering and drilling tool, are all examples of the dead-center lathe. Fig. 5 illustrates the steel turns as used by many English, French and German watchmakers to-day. The Jacot tool is illustrated in Fig. 6, and it, too, is extensively used in the above named countries. The earliest form of live-spindle lathe was known as the Swiss lathe. This lathe, although of the live-spindle type, had a solid and not a hollow spindle, and although an excellent tool in its day, it, too, had to succumb to the advancement of science in

Fig. 6. The Jacot Lathe.

machine building. In one of the forms of this lathe it was so made that the front bearing for the arbor could be made to swing back on a joint, and the workman was thus enabled to take the arbor out with the least amount of trouble without removing the work which had been cemented upon the spindle, and substitute another spindle, if work upon the other had to be temporarily interrupted. It was, however, very weak and shaky, and under a heavy cut would be liable to tremble. The lathe had a clumsy Trest which was held on the bar, that answered for a bed for the lathe in such a manner that the center of the T-rest could not be passed beyond the center of the lathe. The slide-rest which accompanied it was as much too small as

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l 5 the T-rest was too large, and it was absolutely valueless to the watchmaker.

Our remarks above were applied to the Swiss bench lathe and this type should not be confounded with the Swiss universal lathe, for in its day, and for the purpose intended, it was a very superior tool. It had a face plate which usually not only ran true, but presented a perfect plane at right angles to the arbor of the lathe. While the slide rest could not be compared to those used on modern American lathes of to-day, yet it was vastly superior to the ones that accom-

Fig. 7. Swiss Universal Lathe.

panied the Swiss bench lathe. L Fig. 7 illustrates a form of Swiss universal lathe or mandrel which is still to be found on the English, French and German markets and which still retain the faults of the original lathes of nearly fifty years ago. It will be noted that while the universal head is strong and massive, the square bed on which all the resistance comes is weak and does not present surface enough to give a good, solid foundation to the slide rest.

Again the tool is limited in its application to watchmakers' work as the face plate is stationary on its arbor and cannot be removed and chucks substituted. Even when using it to face off work you cannot get at the work to the i6

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extreme edge, as the clamps prevent this. The watchmaker who buys such a machine has at his command a special tool which can only be used for a limited range of work. Again it is a hand tool and the right hand is constantly employed in turning the handle, leaving only the left hand to work with, and the modern watchmaker finds that very often two hands are not enough for some classes of work.

Fig. 8. The Dracip Lathe.

Next in order comes the Bottom lathe, which is doubtless still remembered by the older members of the craft. While this tool was considered a great improvement on the lathes on the market before it, being well made and substantial, yet it, too, faded from view, like snow before a summer sun, when the hollow spindle lathe put in its appearance.

As an example of the tools and methods that are out of date, let us call the attention of the reader to the Dracip lathe, which is a very popular tool among English watch-

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n makers to-day and one which a modern English writer of horological literature extols in the highest terms. Fig. 8 illustrates this lathe ready for work. Like the turns, it is held in the vise, but, unlike it, motion is imparted to the work by means of a hand wheel and catgut cord. The right hand runner is precisely the same as used in the turns but the left hand one is pierced through its entire length to receive runners of less diameter. The inner spindle is a dead one and on its outer end runs a loose pulley from the face of which project two driving pins. This pulley is revolved by

Fig. 9. Dracip Lathe Ready for Drilling.

means of a cord. Now as this loose pulley is rotated, it also rotates the smaller runner by means of the pin, which, sticking out of the body of the latter, projects between the two driving pins and this runner imparts motion to the work by means of the dog and driving pin on the other end, the dog being fastened to the work. Does the reader wonder that we cry out for reform and urge modern methods after this ? The dog and the pin on the inner end of the runner may be seen in Fig. 8, while the two driving pins and the runner pin are more clearly shown in Fig. 9, which shows the lathe ready for drilling. Fig. 10 shows the lathe in position for drilling a pinion by means of a rotating drill, this pinion remaining stationary, and it also shows the real8 THE AMERICAN LATHE.

son for leaving the central slot in the base with its binding screw. The operator selects a suitable cone on the plate held in the T rest holder and centering it from the back he fixes the pinion in its place. The pin which runs from the left hand runner through the wheel is used to prevent the work from rotating while being drilled. He now inserts the drill in the tube and presses against the pinion by means of the rotating thumb-piece at the left. We believe this short description will be sufficient to convey an adequate idea of the Dracip lathe.

Fig. 10. Dracip Lathe Ready to Drill Pinion.

Mr. Charles S. Moseley, inventor of the split-chuck, as used to-day, originated that useful device in 1857 or 1858, to be used upon a solid spindle lathe by substituting a hollow lathe spindle and using a solid rod as the draw-in spindle. These lathes were used in the old Boston Watch Company's factory at Roxbury, Mass., at the time Mr, Moseley was in their employ. Prior to the time of his invention of the split-chuck, wax was used to hold the work in place. Mr. Moseley bored and tapped the end of the solid draw-in spindle for the reception of the chuck, but soon found that this was very unsatisfactory, and he set to work to devise some better form of lathe. The result of his patient toil and thought was the hollow live spindle lathe, with a taper mouth and draw-in spindle, practically as used by American watchmakers to-day. The watchmaking fraternity should be very grateful to Mr. Moseley for his contribution to watchmaking machinery, and yet so modest is he that no man has ever heard him boast of his achievements in this line, although this is but one of many of his inventions, all of which were patentable and none of which were ever patented and hence the low price at which lathes and attachments of various kinds may now be purchased. But to return to our subject.

In 1859, Charles S. Moseley designed for use in the factory of the American Watch Company a small lathe which he conceived would be a useful tool to the watch repairer, and which is the type of all the American watchmakers' lathes. It consists of a round bed secured to a round pedestal by a bolt, the same bolt passing through, and securing the lathe to the bench, headstock and tailstock secured to the bed by screws and nuts, and the headstock taking the split wire chuck.

This lathe only differed from the regular factory lathe by the manner of making the bed and pedestal. One of these lathes was made in the buildings of the American Watch Company, and shown in this country and in England, and then the subject was allowed to lapse, owing to Mr. Moseley becoming connected with the Nashua Watch Company.

While, as before stated, Mr. Moseley's hollow spindle lathe was practically the same as the lathe on the market to-day, yet there were a few points of minor difference, as the shape of the bed, the angles employed, the bearings, etc., and for this reason a diagram of his original lathe may not be devoid of all interest at this point. Fig. n illustrates the bed of the lathe, Fig. 12 the draw-in spindle, Fig. 13

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the chuck and Fig. 14 the hollow spindle. It will be noted that this was not a center guide lathe, although the Moseley Lathe Company now employ that form. It will also be noted that the bed was flat on the under side instead of circular as now made. The dotted lines AA in Fig. 14 represent the interior of the arbor; BB the journal bushings. In 1859, owing to dullness of times, A. Webster, then in charge of the machine shop of the American Watch Company, received orders from Mr. Robbins to reduce the force of machinists. Mr. Webster suggested to Mr. Robbins

Sectional View Original Moseley Lathe.

that a business might be built up of building lathes for watch repairers, and received permission to design such a lathe, and taking the features of the Moseley lathe, changing the proportions and enlarging it, he designed a lathe, to which he added the universal head and the slide rest. A number of these lathes were started, but before completion business revived, so that the full force of machinists were again put upon the factory machinery, and only two of the lathes were sold, the others being put into use in the factory.

Two of the watch company's machinists — Messrs. Kid-

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der and Adams— seeing the work stopped, concluded that it might be a business in which they might safely embark, and they left the factory, started a shop at Stony Brook and, taking the design of Mr. Webster, brought out a lathe, but before many had been sold, the business changed hands several times, until it was finally purchased in 1862 by John Stark, who for a number of years manufactured the lathe. Fig. 15 illustrates one of the earliest lathes placed on the ecAtsia <t */c*su?Gsb'V-s>/*0r0-#c ■

Fig. 15. Earliest Form of Commercial Lathe.

market, with universal head and jeweling caliper in position. The head stock is extremely weak compared with lathes of to-day.

In 1862 great improvements had been made in the details of manufacture of lathes for factory use, by the introduction of hardened spindles' and bearings, and the designing of grinding attachments for the purpose of doing that work, and John E. Whitcomb, thinking that these improved lathes would find a ready sale, left the watch factory and started in business in Boston with George F. Ballou, under the firm name of Ballou, Whitcomb & Co. About the same time Mr. Moseley designed another lathe, and started in the manufacture of the Moseley lathe in Elgin, and for a long time the Whitcomb, the Moseley and the Stark lathes were the only accurately made lathes in the country. In 1876 Mr. Webster connected himself with Mr. Whitcomb, forming the American Watch Tool Co.

In the meantime the Hopkins Watch Tool Company, the Mansfield Watch Tool Company, and the Ohio Watch Tool Company, and two or three other parties in Chicago brought out lathes of various qualities.

In 1889 Mr. Webster designed a lathe known as the Webster-Whitcomb, which shows a decided improvement over the one designed by him some thirty years previous. In the designing of this lathe, Mr. Webster brought the experience of thirty-three years in watch factory work, and in watch tool making. In this lathe the proper proportions of the spindle, its size, length, thickness and shape, received the most careful attention. The proportion of the bearings, the relative sizes of the chucks and the spindles, the form of the tailstock, and a hundred things that tend to make perfection in a lathe, were looked after with great care. The spindle should not be long enough to spring; it should be thick enough to retain its form under the strain that is put upon it, but not so heavy as to make its diameter excessive, and it should run with a minimum amount of friction, i. e., there should not be a hard and an easy place in its revolution.

The length and thickness of the chucks must be such as to give the best possible results, and they should be absolutely true. The threads should be smoothly cut, and the chucks should fit perfectly in the headstock.

While this chapter on the history of the lathe may be devoid of value from a practical standpoint, yet we feel that the modern watchmaker should know something of the evolution of the little machine which occupies the left hand side of his bench and it may have a tendency to instill into him a more wholesome regard for that most useful machine and make him thankful for the devices which the patient application and deep thought of generations of watchmakers have brought forth for his benefit.

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Chapter II. The Construction Of The Watchmaker's Lathe

Perhaps it may be well, in approaching our study of the American Lathe, to state concisely just what its points of merit are and in just what particulars it has, or claims to have, the advantage over the Swiss or Geneva lathe; and also in what respects some of the foreign imitations fail of equal attainments with the genuine. To anyone who has had experience with both, such a statement would be unnecessary ; but as this is not written for such people, and as nearly everyone writing on the subject has contented himself with general expressions of praise for one and contempt for the other, it may be well to set them forth clearly for the benefit of the novice.

In the manufacture of lathes, the vital points are that the spindles of head and tail stocks shall be true, exactly in line with each other at all points of the lathe bed, wherever they may be placed, and that the parts bearing the strains shall be so proportioned mathematically that they will withstand working strains, without springing.

If we go into a machine shop and look at a machinist's, or engine lathe, we shall find a long bed of cast iron with the sides shaped like an I-beam, fastened at the ends and at intervals between them by webs of iron, to prevent the sides from springing. The whole construction exhibits careful thought to arrange the metal so as to best withstand the strains by having the greatest thickness of metal in the same direction as the greatest strain. For this reason the greatest thickness of metal is in a vertical direction; the flanges of the I-beam are wide and fully as thick as the wall of the I ;

z6

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the angles where the wall and flange join are rounded, not, as so many suppose, to make a nice looking job, but in order to get more metal at that point and so provide against lateral as well as vertical strains. On the top of the upper flange are two projecting, inverted V-grooves, the inner one forming the guide for preserving the alignment of the head and tail stocks and the outer performing a like service for the slide rest. They are inverted so as to form a projection instead of a hole, because chips, dirt, etc., would soon fill the

Fig. 17. Sectional View of Engine Tathe.

hole and necessitate cleaning whenever the head or tail stock had to be moved. The top edges of the V are chamfered off, so that tools, etc., falling on them will not bruise them and destroy their accuracy. You will notice in the accompanying sectional view T of the head, Fig. 17, that the point forming the center of the spindle is marked A and the guides for the head and tail stocks B and C. Now our strains are so distributed that when work is done at A the strains will fall within the dotted triangle A, B, C, and the

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2 7 wider the base B, C of the triangle becomes in proportion to its height, the stronger the lathe will be, if the proper proportions of metal are placed in it. You can see at a glance that A, B, C, Fig. 18, is stronger than D, E, F, with the same pressure applied at A and at D.

If we add a slide rest and carry it upon the outer grooves

Fig. 1°. Comparative Strength of Wide and Narrow Triangles.

b and c, Fig. 17, we then have our triangle of forces as A, b, c, in which the base b, c, is still wider; and this is correct, because we take heavier cuts with the slide rest than we do when turning by hand, and consequently more force is exerted.

Fig. 19. English Mandrel.

Now that we understand the triangle of forces, let us examine the watchmakers' lathes. In the old type of lathe, called the mandrel, shown at Fig. 19, we have the earliest and worst form of bed, namely a rectangular bar, with square corners, and its narrowest dimensions forming the base of the triangle of support. In addition to this the necks of the head and tail stocks were cut away so much that not enough metal was left to form a rigid support for the spindles. The bed was square and the holes in the tail stock, slide rest and hand rest shoes had also to be squared to fit it. Anyone who has ever tried fitting square holes will easily see that the difficulties of fitting made uniformity of production of these lathes impossible and this, with the defects mentioned above, caused it to be superseded by the Swiss form of lathe, shown in Fig. 20. This was so much better adapted to unifomity of manufacture that it soon drove the other practically out of the market, although it had a solid spindle and the only way of working was by means of wax chucks and lathe dogs, such as the machinist uses today to revolve some kinds of work.