Rudimentary treatise on the construction of door locks : for commercial and domestic purposes : with Mr. Smyth's letter on the Bramah locks

Preface

The reader is entitled to know the origin of the small work which he holds in his hands.

In August 1852, being about to write a short article on Locks for a Cyclopaedia of Useful Arts, of which I am the editor, I consulted my esteemed and lamented friend, the late Professor Cowper, of King’s College, as to the desirability of explaining to the general reader the defects of some of our English locks, which, previous to the celebrated “lock controversy” of 1851, had borne a high character for skilful construction, beauty of workmanship, and undoubted security. Professor Cowper expressed his strong conviction that by exposing the defects of our locks, the cause of mechanical science, as well as the public in general, would be benefited; that if our locks were defective, inventors would be stimulated to supply the defects, and the art of the locksmith would be raised accordingly. He considered that Mr. Hobbs had made a considerable step in advance in the constructive details of his art, not only in having detected the weak points of some of our best English locks, but also in having introduced two or three new locks, which appeared to be more secure than any of those previously produced. Professor Cowper gave me an introduction to Mr. Hobbs, who placed at my disposal a variety of literary materials relating to the history and construction of locks, and stated his intention at some future time of bringing out a small book on the subject, if he could meet with a publisher. I recom¬ mended him to offer the work to Mr. Weale, for insertion in his series of Rudimentary Works. This was accordingly done, and I was invited to prepare the work ; but as my engagements did not leave me sufficient leisure to write the book, I requested my friend Mr. George Dodd to put the materials together, and to search for

VI

PREFACE.

more. Mr. Dodd acceded to my request; and having completed his part of the work, I subjected it to a careful revision, and added various details which seemed to be necessary to completeness, at least so far as the narrow limits of a small rudimentary work would admit of completeness. The manuscript was then sent to press : each sheet as it was received from the printer was submitted to Mr. Hobbs, who read it with care, and made his annotations and corrections thereon. Mr. Hobbs and I then had a meeting, when the additions and corrections were read and discussed, and ad¬ mitted or rejected as the case might be. The sheet having been thus corrected was sent to press.

It should also be stated that, during the progress of the work, Mr. Weale, at my request, wrote to Messrs. Bramah, and also to Messrs. Chubb, informing them that a Rudimentary Treatise on the Construction of Locks was being prepared, and requesting them to state in writing what alterations or improvements they had made in their locks since the date of the Great Exhibition. The communications which we have received from these celebrated firms are inserted verbatim , in their proper places, in the present work.

Such is the mode in which this small volume has been prepared. I have endeavoured to perform an editor’s duty conscientiously, without entertaining the feeling of a partisan in the matter. My chief object in superintending the production of this book (an ob¬ ject in which the Publisher fully participates) is to advance the cause of mechanical science, and to supply a deficiency in one of the most interesting portions of its English literature.

C. TOMLINSON.

Bedford Place, A mpthill Square,

Contents

*

:hap. page

I. On Locks and Lock-literature.1

Chapter I. On Locks And Lock-literature

The manufacture of locks, and a consideration of the me¬ chanical principles involved in their construction and security, lave never yet been treated with any degree of fulness in an English work. Lock-making has occupied a large amount of ngenuity, and lock-patents have been obtained in considerable lumber, though not always, we are satisfied, with a commen¬ surate return for the expense incurred,—but lock-philosophy if so it may be designated) has not been largely attended to.

And yet it may safely be said that much which is both aechanically and commercially important is comprised in a ock. Every improvement in the manufacture of iron, steel, md brass—that is, in the tool-making and machine-making irocesses—may be made to reflect its light on the locknanufacture; the stamping, the casting, the planing, the lotting, the screw-cutting, the polishing of metals, — all, in >roportion as they are improved, impart some of their aid o the lock-maker. Then, in the finer kinds of locks, the works are so delicate as to approach to the nicety of clock¬ work; thereby combining the manipulative skill of a talented

B

ON LOCKS.

artisan -with the rougher mechanical work of the smith. The principles of mechanical science are also appreciated by many lock-makers. The lever, the inclined plane, the eccentric, the cam, the screw, the wheel and pinion, the ratchet, the spring, —all are brought to bear on the internal mechanism of locks, frequently in many novel combinations.

The commercial importance of locks—though of course never seriously questioned when once fairly brought before one’s attention—has been recently rendered so apparent as to have risen to the position of a public topic. If a strong room, containing gold and silver, notes and bills, books and papers—if such a room be necessarily shielded from intrusion, it becomes no less necessary that the shield should be really worthy of its name, trusty and reliable: a good lock is here nearly as indispensable as a faithful cashier. And without dwelling on such an auriferous picture as a room full of gold, we shall find ample proof of the commercial importance of lock-making in the ordinary circumstances by which we are every day surrounded. Until the world becomes an honest world, or until the honest people bear a larger ratio than at present to the dishonest, the whole of our movables are, more or less, at the mercy of our neighbours. Houses, rooms, vaults, cellars, cabinets, cupboards, caskets, desks, chests, boxes, caddies,— all, with the contents of each, ring the changes between meum and tuurn pretty much according to the security of the locks by which they are guarded.

A commercial, and in some respects a social, doubt has been started within the last year or two, whether or not it is right to discuss so openly the security or insecurity of locks. Many well-meaning persons suppose that the discussion respect¬ ing the means for baffling the supposed safety of locks offers a premium for dishonesty, by shewing others how to be dis¬ honest. This is a fallacy. Rogues are very keen in their profession, and know already much more than we can teach them respecting their several kinds of roguery. Rogues knew a good deal about lock-picking long before locksmiths dis-

ON LOCKS AND LOCK-LITERATURE.

cussed it among themselves, as they have lately done. If a lock—let it have been made in whatever country, or by whatever maker—is not so inviolable as it has hitherto been deemed to be, surely it is to the interest of honest persons to know this fact, because the dishonest are tolerably certain to be the first to apply the knowledge practically; and the spread of the knowledge is necessary to give fair play to those who might suffer by ignorance. It cannot be too earnestly urged, that an acquaintance with real facts will, in the end, be better for all parties. Some time ago, when the reading public was alarmed at being told how London milk is adul¬ terated, timid persons deprecated the exposure, on the plea that it would give instructions in the art of adulterating milk; a vain fear — milkmen knew all about it before, whether they practised it or not; and the exposure only taught purchasers the necessity of a little scrutiny and caution, leaving them to obey this necessity or not, as they pleased. So likewise in respect to bread, sugar, coffee, tea, wine, beer, spirits, vinegar, cheap silks, cheap woollens—all such articles as are suscep¬ tible of debasement by admixture with cheaper substances— much more good than harm is effected by stating candidly and scientifically the various methods by which such debase¬ ment has been, or can be produced. The unscrupulous have the command of much of this kind of knowledge without our aid; and there is moral and commercial justice in placing on their guard those who might possibly suffer therefrom. We employ these stray expressions concerning adulteration, de¬ basement, roguery, and so forth, simply as a mode of illus¬ trating a principle—the advantage of publicity. In respect to lock-making, there can scarcely be such a thing as dis¬ honesty of intention: the inventor produces a lock which he honestly thinks will possess such and such qualities; and he declares his belief to the world. If others differ from him in opinion concerning those qualities, it is open to them to say so; and the discussion, truthfully conducted, must lead to public advantage: the discussion stimulates curiosity, and the

ON LOCKS.

curiosity stimulates invention. Nothing but a partial and limited view of the question could lead to the opinion that harm can result: if there be harm, it will be much more than counterbalanced by good.

The literature of lock-making is, as we have implied, very scanty, both in England and America. The French and Ger¬ mans, though far below our level as lock-makers, are very supe¬ rior to us in their descriptions of the construction and manu¬ facture of locks. Take, for instance, the French treatise pub¬ lished more than eighty years ago by the Academie des Sciences, and forming part of a folio series of manufacturing treatises, illustrated very fully by engravings. It is worth while to exa¬ mine this work, to see how minutely and faithfully the writers of such treatises performed their task nearly a century ago. The Art du Serrurier , with the distinguished name of M. Duhamel du Monceau as the author or editor, was published in 1767. It occupies 290 folio pages, and is illustrated by 42 folio plates. The first chapter gives us an introduction and general principles, in which tho choice and manipulation of ' materials are touched upon; the different qualities of iron and steel; and the processes of forging, founding, welding, stamping, filing, polishing, &c. In the copper-plates represent¬ ing these smiths’ operations and the tools employed,* there is a smithy, with about a dozen smiths engaged in all these various occupations, with stockings down, and a due amount of workshop slovenliness. The next chapter takes us into what may perhaps be called “ smith’s work in general,” or at least it treats of the manufacture of various kinds of iron¬ mongery for doors, windows, and house-fittings generally. Then the third chapter treats of “ smith’s work which serves for the security of houses,” consisting of railings, palings, bars, and gates of various kinds—such at least as are made of iron. In chapter four we have a notice of such kinds of

It is worthy of remark, that the tools described are the same as those which are used by the locksmith at the present day; shewing how little improvement has been made in the means of producing locks.

ON LOCKS AND LOCK-LITERATURE.

smith’s work as relate to the fastenings for doors, windows, closets, chests, &c.; such as hinges, hasps, latches, bolts, and other contrivances less complex than an actual lock. This brings us, by a natural transition, to locks in general, which form the subject of chapter five, to which is attached the illus¬ trious name of M. de Reaumur as the author. Here are given a hundred folio pages of description, illustrated by twenty folio plates relating to locks, lock-making, and locksmiths. The sixth chapter relates to the iron-work of carriages, or the labours of the coachsmiths; while chapter seven, to wind up the work, relates to bell-hanging.

That chapter of the work which has reference to locks is the only one with which Ave have to do here. It is arranged in a systematic manner, beginning with the simpler locks, without wards or tumblers, and proceeding thence to others of more complex construction. The period at which the work Avas Avritten was too early to lead us to expect to find a tumbler-lock described and .delineated : there are, however, numerous examples of single tumbler-locks, many of them of great ingenuity. The use of multiple bolts, that is, of many bolts shot at once by one action of the key, seems to have been familiar enough to the locksmiths of those days. One lock re¬ presented is remarkable; it is attached to a strong and ponder¬ ous coffer or chest. The chest is open; and the whole under or inner surface of the cover is seen to be occupied by a lock of intricate construction; there are no less than twelve bolts, three on each long side, one on each short side, and one in each corner; these bolts are so placed as to catch under a projecting rim fixed round the top of the coffer. The collection of keys, exhibited on a separate plate, is remarkable for the great variety of forms given to them. We shall by and by copy some of the drawings of this curious work.

It was to be expected that in the Encyclopedic Methodique , published in the same country and in the same century, the locksmith’s art would be treated at some such length as in the work just described. Among the two hundred volumes of

ON LOCKS.

which the Cyclopedie consists, several are devoted to arts and manufactures; and one of them contains the article in question. It occupies 168 quarto pages, and is illustrated by 35 copper¬ plate engravings, shewing in detail not only the parts of vari¬ ous locks, but the tools used by the lockmaker. It is proper, however, to remark, that much of the letterpress and many of the plates relate to smith’s work generally, and not ex¬ clusively to lock-work; the French name serrurerie being applied not only to lock-making, but to most of the smith’s work required in dwelling-houses. This affords, indeed, a striking illustration of the fact, that until lately a lock-maker has been regarded rather as a smith than as a machinist, rather as a forger and filer of pieces of iron, than as a fabricator of delicate mechanism. One of the most curious features in this treatise is a vocabulary, containing, in alpha¬ betical arrangement, a minute account of all the French tech¬ nical terms employed in the locksmith’s art. This vocabulary alone occupies 38 quarto pages.

The Germans, like the French, bestow great attention on their treatises relating to the manufacturing arts. Some of these are, indeed, worked up to a degree of minuteness which would seem superfluous, where little distinction is drawn between the importance of fundamental principles and that of mere technical details. Locks have had their due share. The article on locks in Prechtl’s Technological En¬ cyclopaedia written by Karmarsch, and published in 1842, occupies about 140 pages. Locks are very minutely clas¬ sified by the author, according to their purposes and their modes of action, and are illustrated by many plates. One of his classifications is into German, French , and Bastard locks, referring in part to the extent to which the key turns round in the lock; and the last of the three having an intermediate character between the other two. After treating of the ordi¬ nary warded locks, he comes to the combination principle; and it is profitable here to notice, how well the works of our machinists are understood on the continent, when they have

ON LOCKS AND LOCK-LITERATURE. <

any tiling to recommend them; there are a dozen closely printed pages devoted to a minute description of Bramah’s invention, with all the separate parts illustrated by copper¬ plate engravings. After this comes a more general account of the details and manufacture of locks, similarly illustrated by engravings.

Whatever may be the merits of the different articles re¬ lating to locks in the various English cyclopaedias, there are none approaching in length to the article in Prechtls work. But when we consider that Prechtl devotes twenty large vol¬ umes to technological or manufacturing subjects, he is of course able to devote a larger space to each article than is given in English works. Both in England and in America, men are more disposed to do the work than to describe it when done. In the Encyclopaedia Britannica, in Pees’ Cyclo¬ paedia , in Hebert’s Engineers' and Mechanics' Cyclopaedia, in the Encyclopaedia Metropolitana, in the Penny Cyclopaedia , and in other similar works, locks are described as well as can be expected within the limits assigned to the articles. Mr. Bramah’s essay on locks, and on his own lock in particular, is one of the few English pamphlets devoted expressly to this subject. An excerpt from the proceedings of the Institute of Civil Engineers, in 1851, gives an interesting paper on locks by Mi'. Chubb ; and shorter reports of papers and lectures have been published in various ways. Perhaps the best ac¬ count of locks which we have, considering the limited space within which a great deal of information is given in a very clear style, is that contained in Mr. Tomlinson’s Cyclopaedia of Useful Arts.

ON LOCKS.

Chapter II. Ancient Locks : Grecian, Roman, Egyptian

Locks and door-fastenings have not, until modern times, been susceptible of any classified arrangement according to their principles of construction. They have been too simple to re¬ quire it,and too little varied to permit it. That some such fast¬ enings must be employed wherever doors of any kind are used is sufficiently apparent; and there is a little (though only a little) information obtainable, which shews the nature of the fastenings adopted in early times. The bolt, the hasp, the chain, the bar, the latch, the lock, all were known, in one or other of their various forms, in those ages which we are accustomed to consider classical. Travellers, generally speaking, do not de¬ scend to locks, or rather they do not think about them ; otherwise they might have collected much that would have been novel and applicable to the present work; and, indeed, there is some ground for the assertion, that a notice of the door-fastenings of all nations would reveal to us something of the social and domestic habits of various members of the great human family. Be this as it may, however, we may profitably make a little inquiry into the locks of ancient times.

In the volumes of Lardner’s Cyclopedia relating to the u Manners and Customs of the ancient Greeks and Romans,” we do not find any mention of the kinds of locks used by those nations ; but the author, while describing the houses, says :—- U Doors turned anciently upon large pivots in the centre, let into sockets in the lintel and threshold, so that one of the sides opened inwards, the other outwards ; and Plutarch gives the following cnrious reason why persons were to knock and

ANCIENT LOCKS : GRECIAN, ROMAN, EGYPTIAN. 9

alarm the porter, viz. lest the visitor entering unawares should surprise the mistress or daughter of the family busy or undressed, or servants under correction, or the maids quarrel¬ ing.” As the visitors had thus the power (if permitted so to do) to open the outer door of a house, it would appear that very little in the nature of a lock was employed under ordi¬ nary circumstances, unless indeed it were a mere latch. In respect to Roman houses it is stated, that “ the doors revolved upon pivots, which worked in a socket below, and were fast¬ ened by bolts which hung from chains.” There is no mention of locks here. Mr. St. John, in his work on the same subject, says : “ The street-door of a Grecian house, usually, when single, opened outwards ; but when there were folding-doors they opened inwards, as with us. In the former case it was customary, when any one happened to be going forth, to knock, or call, or ring a bell, in order to warn passengers to make way.” After describing the various kinds of wood of which the doors were made, he proceeds : “ The doors at first were fastened by long bars passing into the wall on both sides ; and by degrees smaller bolts, hasps, latches, and locks and keys, succeeded. For example, the outer door of the thalamos in Homer was secured by a silver hasp, and a leathern thong passed round the handle, and tied, perhaps, in a curious knot.

Mr. Yates, in a learned article on this subject in Smith’s Dictionary of Greek and Homan Antiquities , collects numerous details scattered through various early writers. We will string together a few of these details, so far as they have any relation to the fastenings of doors. The outer door of a Roman house was generally called janua; whereas the inner doors were called ostia. The doorway, when complete, consisted of four indispensable parts—the threshold or sill, the lintel, and the two jambs. The threshold, on which the feet trod, was often regarded with a kind of superstitious reverence ; the lintel, which crossed the doorway at the top, having a consideiable superincumbent weight to bear, was usually made of one piece of timber or stone of great strength ; the jambs, or side

b 2

ON LOCKS.

uprights, were also made in one piece each. The doorway, in every building of the least importance, contained two doors folding together; even the internal doors had their bivalve con¬ struction. But in every case each of the two valves was wide enough to allow persons to pass through without opening the other; in some cases even each valve was double, so as to fold like our window-shutters. These doors, or valves, were not hinged to the side-posts, as with us, but were, as has already been stated, pivoted to the lintel above and the threshold be¬ low. The fastening usually consisted of a bolt placed at the base of each valve or half-door, so as to admit of being pushed into a socket made in the sill to receive it. The doorways in some of the houses at Pompeii still shew two holes in the sill, corresponding to the bolts in the two valves. At night, the front door of the house was further secured by means of a wooden and sometimes an iron bar placed across it, and in¬ serted into sockets on each side of the doorway ; hence it was necessary to remove the bar in order to open the door. Chamber-doors were often secured in the same manner. In the Odyssey there is mention of a contrivance (adverted to by Mr. St. John) for bolting or unbolting a door from the out¬ side ; it consisted of a leather thong inserted through a hole in the door, and by means of a loop, ring, or hook, capable of taking hold of the' bolt so as to move it in the manner re¬ quired. We have here evidently the elements of a more com¬ plete mechanism; for the bolt was a rude lock in the same degree that the thong was a rude key. That the Romans afterwards had real locks and keys is clear; for the keys found at Herculaneum and Pompeii, and those attached to rings, prove that a kind of warded lock must have been well known.* There are the remains of a tomb at Pompeii, the door of Avliich is made of a single piece of marble, including the pivots, which were encased in bronze, and turned in sockets of the same metal; it is three feet high, two feet nine inches wide, and

* An examination of the Koman keys in the British Museum sufficiently attests this fact.

ANCIENT LOCKS : GRECIAN. ROMAN, EGYPTIAN.

four and a quarter indies thick ; it is cut in front to resemble panels, and thus approaches nearer in appearance to a modern wooden door ; and it was fastened by some kind of lock, traces of which still remain.

The same facts frequently become more clear when de¬ scribed in different words by different writers. We shall make use of this circumstance. Mr. Donaldson, in his Essay on Ancient Doorways , presents us with details which illustrate many of the foregoing remarks. <£ Homer describes the trea¬ sures and other valuable objects (mentioned in the Odyssey ) as being kept in the citadel, secured merely by a cord intri¬ cately knotted. This, of course, was soon found to be a very insufficient protection, and therefore a wooden bar was adopted inside the doors of houses, to which it was attached by an iron latch, fastened or removed by a key adapted to it; this key was easily applied from within; but in order to get at it from without, a large hole was made in the door, allowing the intro¬ duction of the hand, so as to reach the latch and apply the key. The lock called the Lacedemonian, much celebrated by ancient writers, was invented subsequently; it was especially fitted for the inner chambers of houses, the bar fastenings con¬ tinuing to be employed for closing the outer doors of dwellings and the entrance-gates to cities. The Lacedaemonian lock did not require a hole to be made in the door, for it consisted of a bolt placed on that side of the entrance-door which opened, and on the inside of a chamber-door. When a person who was outside wished to enter, it was necessary for him to in¬ sert the key in a little hole and to raise the bolt; and in time this species of fastening was improved by the insertion of the bolt in an iron frame or rim permanently attached to the door by a chain, and fastening the door by the insertion of the hasp, through the eye of which was forced the bolt inside the lock by applying the key.” After quoting a Latin sentence from Varro in elucidation of his subject, Mr. Donaldson proceeds to observe, that for the most part the locks of the ancients were different in principle from those of modern days, not being in-

ON LOCKS.

serted or mortised into the doors, nor even attached except by a chain; they were, in fact, padlocks.

One of the passages in the Odyssey alluding to the primi¬ tive mode of fastening the valves or folding-doors of a house runs thus :—

“ Whilst to his couch himself the prince addressed.

The silver ring she pulled, the door reclosed ;

The bolt, obedient to the silken cord.

To the strong staple’s inmost depth restored.

Secured the valves.”

Most of the other great nations of antiquity resembled either the Egyptians or the Greeks and Romans, more or less closely, in their domestic and domiciliary arrangements ; or, at any rate, so far as such humble matters as locks and keys are concerned, we need not seek far from those nations for examples. The Nineveh and other Assyrian explorations have, however, revealed many curious and unexpected facts ; from the temples and the palaces we may by and by pene¬ trate into the houses and rooms of the citizens sufficiently to know how their doors were fastened. In the mean time ancient Egypt awaits our notice.

Sir J. Gardner Wilkinson, in his Manners and Customs of the Ancient Egyptians , gives the following information concerning the doors and door-fastenings of that remarkable people, on the authority of models, sculptures, and paintings, still existing. The doors were frequently stained so as to imitate foreign and rare woods. They were either of one or two valves, turn¬ ing on pieces of metal, and were secured within by a bar or by bolts. Some of these bronze pins have been discovered in the tombs of Thebes ; they were fastened to the wood with nails of the same metal, the round heads of which served also as orna¬ ments. In the stone lintels and floors behind the thresholds of the tombs and temples are still frequently to be seen the holes in which the pivot-pins turned, as well as those of the

ANCIENT LOCKS : GEE Cl AN, ROMAN, EGYPTIAN.

bolts and bars, and the recess for receiving the opened valves. The folding-doors had bolts in the centre, sometimes above as well as below; a bar was placed across from one wall to the other.

In many of the ancient Egyptian doors there were wooden locks fixed so as to fasten across the centre at the junction where the two folds of the door met. It is difficult, by mere inspection of the bas-reliefs and paintings, to decide whether these locks were opened by a key, or were merely drawn back¬ wards and forwards like a bolt; but if they were really locks, it is probable that they were on the same principle as the Egyp¬ tian lock still in use. For greater security, these modern locks are occasionally sealed with a mass of clay ; and there is sa¬ tisfactory evidence that the same custom was frequently ob¬ served among the ancient inhabitants of that country. Sir J. G. Wilkinson gives a representation of an iron key, now in his possession, which he procured among the tombs at Thebes, and which looks very much like a modern burglar’s picklock. In relation to keys generally, and after mentioning the use of bronze for their manufacture, he says: “:At a later period, when iron came into general use, keys were made of that metal, and consisted of a straight shank about five inches in length, and a bar at right angles with it, on which were three or more projecting teeth. The ring at the upper extremity was intended for the same purpose as that of our modern keys ; but we are ignorant of the exact time when they were brought into use; and the first invention of locks distinct from both is equally uncertain; nor do I know of any positive mention of a key, which, like our own, could be taken out of the lock, previous to the year 1336 before our era; and this is stated to have been used to fasten the door of the summer parlour of Eglon, the king of Moab. The description here adverted to is that contained in Judges iii. .23-25 : 1 Ehud went forth through the porch, and shut the doors of the parlour upon him, and locked them .... his servants .... took a key, and opened them.’ ”