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Transcriber’s note:
Text enclosed by underscores is in italics (_italics_).
Small capitals have been transcribed as ALL CAPITALS.
A detailed transcriber’s note can be found at the end of
this text.
RUDIMENTARY TREATISE
ON THE
CONSTRUCTION OF LOCKS.
London:
Printed by Levey, Robson, and Franklyn,
Great New Street and Fetter Lane.
RUDIMENTARY TREATISE
ON THE
CONSTRUCTION OF LOCKS.
Edited by
CHARLES TOMLINSON.
“Il n’y a point de machines plus communes que les serrures: elles sont
assez composées pour mériter le nom de _machine_; mais je ne sais s’il
y en a qui soient aussi peu connues par ceux qui les emploient. Il est
rare qu’on sache en quoi consiste la bonté d’une serrure, le degré de
sûreté qu’on peut s’en promettre. Leur extérieur est presque la seule
chose à quoi l’on s’arrête. Les usages importans auxquels elles sont
employées devraient cependant exciter la curiosité à les connaître, si
la curiosité était toujours excitée raisonnablement.”--M. DE RÉAUMUR,
“_Des Serrures de toutes les espèces_,” forming the fifth chapter of
M. Duhamel’s Treatise “_Art du Serrurier_,” in the “_Descriptions des
Arts et Metiers faites ou approuvées par Messieurs de l’Académie
Royale des Sciences_.”
London:
John Weale, 59 High Holborn.
MDCCCLIII.
“There are no machines more common than locks: they are sufficiently
complex to merit the name of _machine_; but I know of no others the
structure of which is so little understood by those who use them. It
is rare to find any one who knows wherein the goodness of a lock
consists, or the degree of security that he can attach to it. The
outside of a lock is usually all that attracts attention. Doubtless
the important uses to which locks are applied would excite curiosity
respecting their structure, if curiosity were always excited for
worthy objects.”--M. DE RÉAUMUR.
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
Cyclopædia 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 recommended 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 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
admitted 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 object 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, Ampthill Square,
July 1853._
ADVERTISEMENT.
The first edition of this volume, though at the date of its appearance
co-ordinating with the state of knowledge of the period, and containing
matter well arranged and lucidly described--as must have been expected
from the reputation of its author--had, through the lapse of the few
intervening years, inevitably become somewhat behind the state of the
art of which it treats--one which is daily receiving the attentive
consideration of many skilful men, and occasional marked improvements.
Amongst those of later years none are more noteworthy than the locks
patented by Mr. Fenby, of Birmingham; of these an account, with accurate
illustrations, for which the drawings are supplied by the inventor, is
now added,--together with a brief essay upon the important but popularly
ill-understood subject of iron safes.
ROBERT MALLET.
_April, 1868._
In reference to Mr. Smyth’s letter, which is given at pp. 130, 131, that
gentleman is desirous to state that it was in consequence of the defects
there pointed out that Mr. Hobbs was enabled to pick the Bramah lock
operated upon, which had been manufactured forty years previously, when
the sliders were made of iron instead of steel as they now are, and yet,
notwithstanding that and the other defects pointed out, it took Mr.
Hobbs sixteen days to pick it. In proof of the security of the Bramah
lock, Mr. Smyth mentions that Mr. Hobbs’s best workman failed in picking
an ordinary 3-inch Bramah box lock; and that a person in the employ of
Messrs. Johnson and Ravey, of Conduit Street, failed also in his attempt
to pick a 6-inch cellar-door lock, though he had the lock in his
possession for twelve months, employing his evenings in making
instruments and trying to pick it. Mr. Smyth contradicts the statement
made at page 128, that the new lock was removed from the window through
any fear of its being opened. On the contrary, it was put up especially
to afford an opportunity for Mr. Hobbs to make, if he thought fit,
another trial, and it remained in the window four months. The sole cause
of its removal was to stop the impertinent applications of men and boys,
which interfered too much with the general business of the firm.
CONTENTS.
CHAP. PAGE
I. On Locks and Lock-literature 1
II. Ancient Locks: Grecian, Roman, Egyptian 8
III. Lock classification. The Puzzle-Lock and the Dial-Lock 16
IV. Warded Locks, with their varied appendages 27
V. On Tumbler or Lever Locks 43
VI. The Bramah Lock 64
VII. American Locks 82
VIII. The Lock Controversy: previous to the date of the Great
Exhibition 102
IX. The Lock Controversy: during and since the time of the
Great Exhibition 115
X. Effects of the Great Exhibition of 1851 in improving
English Locks 140
XI. The Lock and Key Manufacture 154
XII. English Patents for Locks. Aubin’s Lock Trophy. Conclusion 164
APPENDIX.
XIII. On an Improved Construction of Lock and Key: Fenby’s Adytic
Lock 176
XIV. Fenby’s Stop Lock 193
XV. Note upon Iron Safes 201
ON THE
CONSTRUCTION OF LOCKS.
CHAPTER I.
ON LOCKS AND LOCK-LITERATURE.
The manufacture of locks, and a consideration of the mechanical
principles involved in their construction and security, have never yet
been treated with any degree of fulness in an English work. Lock-making
has occupied a large amount of ingenuity, and lock-patents have been
obtained in considerable number, though not always, we are satisfied,
with a commensurate 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 mechanically and
commercially important is comprised in a lock. Every improvement in the
manufacture of iron, steel, and brass--that is, in the tool-making and
machine-making processes--may be made to reflect its light on the
lock-manufacture; the stamping, the casting, the planing, the slotting,
the screw-cutting, the polishing of metals,--all, in proportion as they
are improved, impart some of their aid to the lock-maker. Then, in the
finer kinds of locks, the works are so delicate as to approach to the
nicety of clockwork; thereby combining the manipulative skill of a
talented 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 fall 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 _tuum_ 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 respecting the means for baffling the
supposed safety of locks offers a premium for dishonesty, by shewing
others how to be dishonest. 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 discussed 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
adulterated, 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 susceptible 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 debasement 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, debasement,
roguery, and so forth, simply as a mode of illustrating a principle--the
advantage of publicity. In respect to lock-making, there can scarcely be
such a thing as dishonesty 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 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 Germans, though far below our
level as lock-makers, are very superior to us in their descriptions of
the construction and manufacture of locks. Take, for instance, the
French treatise published more than eighty years ago by the _Académie
des Sciences_, and forming part of a folio series of manufacturing
treatises, illustrated very fully by engravings. It is worth while to
examine 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 the 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 representing these
smiths’ operations and the tools employed,[1] 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
ironmongery 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 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 illustrious name of M.
de Réaumur 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.
[1] 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.
That chapter of the work which has reference to locks is the only one
with which we 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 was written 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 represented is remarkable; it is attached to a
strong and ponderous 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 _Encyclopédie Méthodique_, 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 which the _Cyclopédie_ 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 various
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 exclusively 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 alphabetical arrangement, a minute account of all the
French technical 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 Encyclopædia_ written by
Karmarsch, and published in 1842, occupies about 140 pages. Locks are
very minutely classified 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 ordinary 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 any thing 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 relating to locks
in the various English cyclopædias, there are none approaching in length
to the article in Prechtl’s work. But when we consider that Prechtl
devotes twenty large volumes 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
_Encyclopædia Britannica_, in Rees’ _Cyclopædia_, in Hebert’s
_Engineers’ and Mechanics’ Cyclopædia_, in the _Encyclopædia
Metropolitana_, in the _Penny Cyclopædia_, 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 Mr. Chubb; and shorter reports of papers and lectures have been
published in various ways. Perhaps the best account 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 _Cyclopædia of Useful Arts_.