CHAPTER XIV._Rudimentary Treatise on the Construction of Locks

FENBY’S PATENT STOP-LOCK.

This lock has been designed with a view to doing away with several weak

points in the construction of lever locks.

The introduction of the movable stump by Mr. Hobbs, in order to defeat

picking by the tentative method of applying pressure to the bolt, so as

to cause binding between the stump and the levers, was a great advance

in the art of lock-making.

The movable stump, as so constructed, was, however, open to this

objection, that while sufficiently delicate and certain in its action to

render picking very difficult, it was at the same time, through the

smallness of its parts--resulting from the confined space available for

its action--unsuited to withstand any amount of force applied to push

back the bolt.

[Illustration: fig. 65.]

In the lock under notice the stump _s_ is formed in the solid on the

shorter arm _a_¹ of a cranked lever or oscillating stop _a_. This stop

_a_ works on the steel pin or centre _b_, which latter has a bearing in

both plates of the lock. At the end _a_ of the stop _a_ is a recess

formed to fit the corner _d_ of the bolt-head. _c_ is a stud limiting

the range of _a_ in an upward direction, so that when in its normal

position the stop _a_ may just clear the bolt-head, as shown in figs.

65, 66, and 67. The tail of the bolt, instead of being in the form

usually adopted, is formed of the bar _e_ set on edge so as to reach

from the back to the front plate of the lock, completely dividing the

lower part, in which the keyhole lies, from the upper, in which the main

parts of the works are placed.

This bar _e_ works between the guide pieces _g g_, so that in whatever

position the bolt may be, the division of the lock into two chambers is

complete. At _f_ is the recess in which the key acts to move the bolt.

The levers _l_ turn upon the pin _i_ formed in the solid of the

bolt-head. The part of each lever on which the key is to act passes

through a slot or recess in _e_, the parts _h_ and _h_¹ of the levers

being struck to the arcs of circles, having their centres coincident

with that upon which the levers turn at _i_.

As it is not possible to lift the levers out of this slot in the bar

_e_, and further, as the levers and bolt move together in a longitudinal

direction, the movements necessary to locking and unlocking open no

communication between the upper and lower chambers of the lock.

The springs of the levers are formed out of the solid metal of the

levers themselves, and are thus not liable to that displacement which so

often occurs with separate springs, nor to the corrosion by oxidation

incidental to steel springs. They are cut round the corner, and down the

front of the lever, to gain greater elasticity.

In fig. 65 the lock is shown with the front plate removed, and the works

as they stand when unlocked. Fig. 66 is the same, except that the works

are shown locked, and the back plate removed instead of the front. Fig.

67 shows the _front_ view of fig. 66. Fig. 68 shows the result of any

attempt to pick the lock by pressure.

[Illustration: fig. 66.]

[Illustration: fig. 67.]

[Illustration: fig. 68.]

The lock being locked, as shown in figs. 66 and 67, it will be seen that

the stop _a_ just clears the angle _d_ of the bolt-head. Further, that

the gatings _r_ of the levers _l_ cannot pass the stump _s_, unless the

levers be so lifted as to coincide with each other and the stump. The

stop _a_ being held up by a very light pressure from the lever springs,

a small force applied to the stump _s_ is sufficient to upset its

equilibrium, and bring down its end _a_² upon the bolt-head at _d_, as

shown in fig. 68. This occurs whenever an attempt is made to “_feel_”

the stump with the levers; and not only does the stop _a_ free the

levers from all pressure, and so preserve them and the stump from

injury, and the lock from being picked, but it also forms a strut for

securing the bolt: in fact, no violence short of that necessary to shear

the pin _b_ can make the bolt yield.

The drawings show a mortise lock, but the improvements shown are

universally applicable in the construction of locks of all kinds.

For the manufacture of these and other locks, and kindred articles,

Messrs. J. B. Fenby and Co., engineers of the Liverpool Works,

Birmingham, have put up, from the designs of their managing partner, Mr.

J. Beverley Fenby, an experimental set of machinery, almost entirely

self-acting, and calculated to turn out large quantities of the

component parts of locks and other articles with extreme accuracy and

rapidity.

The whole set works on the interchangeable system--as already in use for

military small arms. It is not, however, to be supposed that, because

the parts of the locks are interchangeable, one key will open several

locks--such a source of insecurity being guarded against by the

permutating key-cutting machines invented by Mr. Fenby. These machines

give complete command over the making of keys, whether it be required to

make a comparatively unlimited number, all differing from each other, to

make a number alike, or to make sets with master keys.

Atmospheric and hydraulic pressure also plays an important part in

shaping many of the parts of the locks.

NOTE UPON IRON SAFES.

At the conclusion of this work upon locks it will not be out of place to

make a few remarks upon the degree of real safety that attaches to what

are commonly called “safes,” and to point out in a common-sense way what

are the chief dangers that these may incur from depredators (whether

burglars or in times of public anarchy and violence), and what are the

main conditions to be relied upon for safety--assuming that, by one or

other of the constructions pointed out in the preceding pages, the

_lock_ of the safe be such as to be practically unpickable, and that

carelessness shall not have placed the true key in the possession of the

thief.

There can be no doubt upon the mind of any mechanic or engineer,

thoroughly acquainted with practical working in metals, that a

good deal of what has been brought forward and affirmed, both by

safe-makers and by burglars themselves (turned approvers), as to the

wonderfully-ingenious devices resorted to by the latter, by which, if we

were to believe it all, nothing in the shape of steel or iron can

possibly withstand ultimately the redoubtable powers of these people, is

simply fiction--imaginary ingenuity utterly impracticable if tried.

Such, for example, is the notion of its being possible, by an ounce or

two of gunpowder exploded in the interior, to so blow asunder and

dislocate the parts of a well-made safe-lock that the bolts shall then

be easily got loose, or that a steel-plated safe which resists the drill

can be softened “by the blowpipe.” And just as absurd are some of the

wonderful pieces of ingenuity by which some of the burglars’ actual

devices are supposed to be met and frustrated; as, for example, one for

which we believe a patent has been obtained, consisting in filling-in

the hollow space between the inside and outside plates of the safe with

cast-iron bullets left loose. These might, no doubt, break a

_flat_-stemmed drill, after that had pierced the outer plate, but could

have no effect whatever upon a _round_-shanked drill, such as one of the

ordinary American spiral, or _teredo_-pointed drills.

That there are some methods of violence still untried, and yet at the

command of the burglar who dares to risk a tolerably loud noise of

explosive agents, is well known to skilful mechanical engineers, and for

obvious reasons it would be unwise that we should give any information

as to such; but the real practical and too-often effectual methods of

the burglar limit themselves almost entirely to the use of the

succession of steel wedges, followed by the powerful steel-pointed

pinching bar, or bars, to the forcing or prizing-screw, and to making

more or less way for this by cutting out beforehand by the pin-drill.

A safe, to be safe, must be so circumstanced or so constructed, or both,

that it should be able to resist the best efforts that can be made by

these methods for several hours; perhaps we might say as much as thirty

to thirty-six hours--viz., from Saturday night to Monday morning.

Now we hesitate not to say that the unsafeness of “safes” arises not

from any structural difficulty whatever, but almost always from the

parsimony and ignorance of those who purchase and employ them. Safes,

like razors, are made to sell, and if the public demand is for cheap

safes, such as we see every day advertised in the newspapers, it was

sure to have been, and is, met by a supply of things called safes which

are utterly unsafe. The great mass of the showy green and gold gewgaws

that one sees in the safe-shop windows, with flaming testimonials as to

their fire and burglar-proof powers, are simple shams: a genuine safe

could not be made at their prices.

The very first condition to constitute a genuine safe is that it shall

have an ample mass of metal--_i.e._, not of cast-iron, but of

wrought-iron, or best of steel, all round it; and especially that the

margins of metal all round the door shall be of such huge and surplus

scantling that no amount of wedging, by construction possible, should

be able to bend any one side sensibly. The next is that the workmanship

of every part of the safe be first-class: not that there be merely a

moulded door with a showy lock and a trumpery brass-plate upon it, but

that every corner and joint of plate with plate in sides and back be

effectually united and jointed in the best manner, and that the fitting

of the hardened edges of the door shall be like those of a valve, and

not even let a watch-spring be got in between. If these obvious

conditions be observed, and that the safe itself be properly posited in

the premises, it will be found, even with ordinary forms of construction

as to doors and bolts, but with a really unpickable lock, a very hard

nut for the best burglar to crack.

[Illustration: Chatwood’s Safes.]

But much more may be effected without any serious increase of cost.

Several forms of safes are now made, the rabbets of the doors of which

are so formed that it is almost a physical impossibility to get any

wedge, however thin, to drive in between the door and the frame. This is

effected in Chatwood’s patent safes (of Bolton and Manchester), as

figured above, by making the door rabbets in cross section

_curvilinear_, so that even if the fit be not so perfect but that the

edges of a very thin wedge can still be inserted, it yet cannot be

driven--for, as it goes forward, it must become curved, and if soft, so

as thus to bend, the thin steel will not bear the severe strain of

driving, but if hard, it breaks off into short bits close to the

entrance. In addition to this Chatwood’s (and we believe other makers’)

safes have bolts so constructed, as seen in the figure, that they _hook_

or lock into the bolt recesses in the frame in such a manner as to hold

the opposite sides of the frame together, so that, independent of its

own proper stiffness, it cannot be bent anywhere, unless by tearing

asunder the end on the iron bar constituting each cross-bolt. The bolts,

in fact, not only secure the door (as in ordinary) from opening, but

secure the door and frame together. With such a safe, if the owner will

only provide a proper position for it in his premises, he may rest

pretty easy in mind.

Safes are very commonly stood upon a wooden floor, or made to form part

of a wood-framed bookcase, or press, or stand in a recess. Often they

are comeatable all round, and even underneath, with nought but an inch

board below them, and almost always they are left with the front door

freely and fully exposed, and with ample and convenient room left all

round. This for two or three workmen to manipulate the safe as they may.

Now the only real conditions of safety are that the iron safe should be

bedded into brickwork set in Portland cement and sand; or, what is much

better, in hard granite or gritstone masonry, bedded in like manner.

Without this be done, a fire-proof safe is simply a delusion;

constructed how it may be, it is only a crucible of more or less

badly-conducting power, in which, after a time longer or shorter, deeds,

bank-notes, documents, &c., will be calcined, and coin or jewellery

melted, and gems flawed and destroyed. We say this in the full face of

the delusive so-called “fiery ordeals” to which many of the so-called

double-cased fire-proof safes are alleged to have been for hours

exposed. The safe should always be embedded in masonry, and rest upon

that in such a way that it cannot get undermined by either fire or

burglars.

Whenever the premises admit of it, the door of the safe itself should be

set back 10 or 12 inches from the face of the wall in which it is

embedded, and an outer door, flush with the face of the wall, should be

provided of iron, with a good lock and multiple bolts. The door of the

safe should open to the right; and if so, the outer door should open to

the left; and neither should open more than square to their position

when shut. No one but a practical workman or engineer can have an

adequate notion of the extent to which any mechanical operation upon the

door of a safe thus circumstanced is hampered by its being set back into

the wall, and with an outer door that even when open, cuts off all ready

manual access to the inner door from one side.

When premises are constructed, as they should be for all banks and

bullion merchants, jewellers, &c., having special regard to a safe as an

indisputably secure depository, then the safe should be completely iron

or steel cased, and embedded in hard stone masonry (we shall not here go

into additional special precautions against the remoter effects of

fire), covered in with a strong fire-brick arch, and with nothing but

the solid ground below. The door of the safe should only be approachable

through an iron or stone-lined passage, just the size of the safe-door,

and no more. This should be some feet in length, and have an outer

double-cased steel door, or perhaps that and an intermediate iron

falling-door or portcullis, between the outer door and the safe-door.

With a safe-door so circumstanced, even supposing both these outer doors

forced and open, it is almost impracticable for even a single workman,

however agile or adroit, to perform any mechanical operation whatever

upon the door, least of all upon its surrounding rabbates. These are so

close to the solid granite walls, starting out at right angles from the

rabbate all round, that he has no room to do anything; and to get a

prizing-bar at the door-rabbate, or even to get a second man to assist

the first in any way, is impossible, simply for want of room.

The whole of the doors and all the surfaces of such passage should be

painted a dull, lustreless black. No one who has not tried it, has any

idea of the difficulty of illuminating such a black passage, by even

several candles, sufficiently to perform any delicate mechanical

operation; and good light is essential to the safe-breaker.

In banks there is no better plan than has been ere now adopted of making

the iron safe a great cube, with the door at one side, placing the whole

safe with its bottom resting upon the stem or plunger of an hydraulic

press, the cylinder of which is fixed in the bottom of the pit in the

solid earth, of a size capable of enabling the whole safe to be bodily

lowered down into the cavity at the end of the day’s work, and pumped up

again out of its hiding-place the next morning. The lever of the

hydraulic pump is taken away, and the socket into which it fits is

plugged, and the plug locked into its place, and then the pump--situated

in a recess in solid masonry--is itself locked up. The top of the safe

itself, when it has been lowered to the bottom of its chamber, stands 10

or 12 inches below the floor-level of the stone floor, and a pair of

iron doors is then closed over it and locked down.

A safe executed in this way, though requiring a considerable expenditure

at first, if well done, might bid defiance to anything almost, even

unlimited gunpowder, for some days. The only addition of safety that

almost could be conceived would be that adopted at the bullion vaults of

the Bank of France in Paris, where these, situated in casemates two

stories under ground, are only approachable by one narrow, winding

staircase, which can be itself, in case of emergency, rapidly rendered

useless, and the cylindrical well in which it is placed filled up with

about 30 feet in depth of water, which cannot be pumped out until a

continuous supply be shut off by distant means only known to one or two

trusted employés.

Since this revision has been in type the great “safes’ contest” or wager

of battle between the rival safes of Mr. Herring of New York, and Mr.

Chatwood of Bolton, for £600 a side, has come off, at the International

Exhibition, Paris, Mr. R. Mallet and Mr. Robert F. Fairlie, C.E., being

the representatives of the English interests upon the occasion. The

result, which, owing to the conduct of some of the parties concerned,

assumed an unpleasant and incomplete form, may be found detailed fully

in a pamphlet published by Tinsley Brothers, London. It is referred to

here because, although no decision of the wager made could be come to,

the facts ascertained are of great interest and importance as respects

the proper construction of safes. They show conclusively that an

effectively constructed door and jambs is really the one thing needful

to absolute security, provided the safe itself be built up, as we have

urged, into masonry.

They also show that there are good grounds for doubting that the

American (Herring’s) “safe within safe” construction, with a thick mass

of so-called fire-proofing powdery composition between them, is at all

as protective against mere violence and the persevering use of wedges,

as Chatwood’s simpler but far more effective construction, especially of

his door and jambs. If one of the latter safes, wholly of steel plating,

be fairly embedded into masonry, and another outside flush door of his

construction, with curved rabbates and hooking locking bolts, be

supplied to the masonry ope itself, it is scarcely an exaggeration to

call such a safe “Invincible,” so far as anything that burglars, in any

civilised place in Europe at least, can effect.

INDEX.

Adytic lock, 176;

machine for manufacturing the keys of the, 185;

number of changes in the lock, 188;

advantages of, 189;

discussion on its value, 192.

Ainger on the Bramah lock, 111.

Ainger’s lock, 61.

Alarum lock, 40.

American locks, 82;

Stansbury’s lock, 83;

Yale’s lock, 83;

Dr. Andrews’s lock, 84;

Day and Newell’s locks, 86;

their Parautoptic lock, 89;

Hobbs’s Protector lock, 99.

Ancient locks, 8.

Andrews’s lock, 84;

snail wheel lock, 85.

Appendix, 173.

Aubin’s lock trophy, 166;

locks forming it described, 168.

Barron’s tumbler lock, 49;

Bramah on, 68.

Bird’s tumbler lock, 52.

Bramah on Barron’s tumbler lock, 68;

on the defects of the tumbler lock, 68;

on the defects of the warded lock, 66.

Bramah lock, 70;

cylinder lock, 73;

number of changes in the Bramah lock, 81;

picked by Mr. Hobbs, 121;

report of the arbitrators, 123, 124;

a description of the lock picked, 125;

letters from Messrs. Bramah questioning the fairness of the trial,

126;

method of picking, 110;

method employed by Mr. Hobbs, 129;

Ainger on the Bramah lock, 110;

Farey on the Bramah lock, 113;

improvements made since 1851, 131.

Brown’s letter lock, 23;

picked by Mr. Hobbs, 139.

Bullion vaults of the Bank of France, 206.

Chatwood’s safes described, 203.

Chinese locks, 171.

Chubb on Davies’s lock, 112;

on lock picking, 132.

Chubb’s lock, 53;

described, 54, 56;

key of, 57;

attempt to pick, 58;

experiments on, 59;

number of changes in the lock, 55;

the detector lock picked by Mr. Hobbs, 115;

value of the detector questioned, 117;

improvements, 121;

Mr. Hodge on the Chubb lock, 114;

Chubb’s new locks, 147;

bank locks, 149.

Clockwork, application of, to locks, 39.

Closet-lock, 17.

Commercial importance of locks, 2.

Contrivances for adding to the security of locks, 35.

Cut locks, 18.

Davies’s lock, Captain O’Brien on 112;

Mr. Chubb on, 112.

Davis’s lock, 60.

Day and Newell’s lock, 86;

Parautoptic lock, 89 _et seq._

Dead-lock, 17.

Denison’s large lock, 142;

small ditto, 146.

Dial locks, 23;

method of picking, 138.

Duhamel du Monceau’s _Art du Serrurier_, 4.

Egyptian door-fastenings, 13.

Egyptian pin-lock, 14;

method of picking, 139.

Escutcheon, uses of the, explained, 37.

Exhibition of 1851, effects of the, in improving English locks, 140;

Jury Report on locks, 131;

observations on the Report, 133.

Farey on the Bramah lock, 113.

Fenby on warded locks, 173;

on tumbler locks, 174.

Fenby’s adytic lock, 176;

machine for making the keys of, 185;

number of changes in the, 188;

advantages of, 189;

discussion on the value of the lock, 192;

stop-lock, 196;

machines for the manufacture of the locks, 200.

Fons, Mr. de la, his improvement in locks, 148.

French locks, ancient, 32.

Friend’s secret lock, 39.

Greek locks, 9.

Hobbs on English locks made before 1851, 115;

he picks a Chubb lock, 116;

a Bramah lock picked by Mr. Hobbs, 122;

his mode of picking the Bramah lock described, 129;

Mr. Brown’s letter-lock picked by him, 139.

Hobbs’s protector lock, 99.

Hodge on the Chubb lock, 114.

Iron-rim lock, 17.

Iron safes, value of, 201;

the best position for a safe, 204;

chamber for jewellers’ safes described, 205;

arrangement of bank safes, 205;

Chatwood’s safes, 203.

Kemp’s union lock, 81.

Keys, master, 31;

skeleton, 30;

Mackinnon’s key, 62;

Machin’s web key, 154.

Knob lock, 17.

Lacedæmonian lock, 11.

Left-hand lock, 17.

Letter locks, 22;

method of picking, 138.

Lever locks, 43.

Literature of lock-making, 4;

list of references to the “Transactions of the Society of Arts”

relating to lock-making, 166.

Lock classification, 17.

Lock controversy, 102;

previous to the Great Exhibition, 103;

Mr. Chubb on Davies’s lock, 112;

Captain O’Brien on Davies’s and other locks, 112;

Mr. Farey on the Bramah lock, 113;

Mr. Hodge on locks, 114;

lock controversy during and since the Great Exhibition, 115;

Mr. Hobbs on English locks, 115;

he picks the Chubb lock, 116;

the Bramah lock picked by him, 121;

statements of Messrs. Bramah, 125;

attempt of Messrs. Garbutt to pick the parautoptic lock, 134.

Lock manufacture at Wolverhampton, state of, described, 154.

Lock-picking, distinction between “picking” and “ringing the changes”

on a lock, 136;

tentative process of picking, 110;

method of picking letter and dial locks, 138;

mode of picking the Egyptian lock, 139;

method of picking tumbler locks, 118;

method of picking the Yale lock, 140;

Mr. Chubb on lock-picking, 132;

contrivances to prevent the picking of locks, 105.

Lock trophy, Aubin’s, 166;

locks composing the, described, 168.

Lock and key, improved, 176.

Locks, English patents for, 164;

Jury Report, Exhibition of 1851, on, 131;

observations on the Report, 133;

effects of the Exhibition of 1851 in improving English locks, 140;

use of machinery in the manufacture of, 163, 200.

Locks, &c., invented by the Marquis of Worcester, 35.

Locks and keys, literature of, 4;

list of references in the “Transactions of the Society of Arts”

relating to, 166.

Louis XVI., his fondness for lock-making, 26, 35.

Machin’s web key, 61.

Mackinnon’s key, 62.

Manufacture of locks and keys at Wolverhampton, state of the, 154.

Marshall’s secret escutcheon, 37.

Master keys, 31.

Meighan’s alarum lock, 40.

Mitchell and Lawton’s tumbler lock, 52.

Mortise locks, 17, 18.

Multiple-bolt locks, 41,

Nettlefold’s lock, 60.

Newell’s parautoptic lock, 89.

O’Brien, Captain, on Davies’s lock, 112.

Owen’s experiments on Chubb and Bramah locks, 59.

Parautoptic lock, 89;

key, 91;

Austrian Report on, 93;

English patent for, 98;

attempts to pick the, in America, 106;

Report of the American Institute on the lock, 107;

latest challenge issued by Messrs. Day and Newell, 108;

Mr. Garbutt’s attempt to pick the, 134;

failure of the attempt, 135.

Parnell’s defiance lock, 141.

Parson’s lock, 61.

Patents, English, for locks, 164.

Pin-lock of Egypt, 14.

Puzzle-lock, 19.

Regnier’s puzzle locks, 21.

Right-hand lock, 17.

Ring lock, 17.

Roman locks, 10.

Rowntree’s tumbler lock, 50.

Russell’s screw-lock for casks, 38.

Russian locks, 171.

Rutherford’s lock, 39.

Ruxton’s detector for tumbler locks, 53.

Safes, value of iron, 201;

Chatwood’s, 203;