[Illustration: THE CARPENTER’S SHOP.]
An account of the tools and implements used for working in wood would
scarcely be complete without some remarks upon wood itself, and you can
have no better information on this subject than that which has been
written by a gentleman[1] who is thoroughly acquainted with the different
kinds of timber, and with all the materials used in building.
[1] Mr. E. DOBSON, Assoc. Inst. C. E.
If we examine a transverse section of the stem of a tree, we perceive
it to consist of three distinct parts; the _bark_, the _wood_, and the
_pith_. The wood appears disposed in rings round the pith, the outer
rings being softer, and containing more sap, than those immediately round
the pith, which form what is called the _heart-wood_.
These rings are also traversed by rays extending from the centre of the
stem to the bark, called _medullary rays_.
The whole structure of a tree consists of minute vessels and cells, the
former conveying the sap through the wood in its ascent, and through
the bark to the leaves in its descent; and the latter performing the
functions of secretion and nutrition during the life of the tree. The
solid parts of a tree consist almost entirely of the fibrous parts
composing the sides of the vessels and cells.
By numerous experiments it has been ascertained that the sap begins to
ascend in the spring of the year, through the minute vessels in the wood,
and descends through the bark to the leaves, and, after passing through
them, is deposited in an altered state between the bark and the last
year’s wood, forming a new layer of bark and sap-wood, the old bark being
pushed forward.
As the annual layers increase in number, the sap-wood ceases to perform
its original functions; the fluid parts are evaporated or absorbed by the
new wood, and, the sides of the vessels being pressed together by the
growth of the latter, the sap-wood becomes heart-wood or perfect wood,
and until this change takes place it is unfit for the purposes of the
builder.
The vessels in each layer of wood are largest on the side nearest the
centre of the stem, and smallest at the outside. This arises from the
first being formed in the spring, when vegetation is most active. The
oblong cells which surround the vessels are filled with fluids in the
early growth; but, as the tree increases in size, these become evaporated
and absorbed; and the cells become partly filled with depositions of
woody matter and indurated secretions, depending on the nature of the
soil, and affecting the quality of the timber. Thus Honduras mahogany
is full of black specks, while the Spanish is full of minute white
particles, giving the wood the appearance of having been rubbed over with
chalk.
The best time for felling trees is either in mid-winter, when the sap has
ceased to flow, or in midsummer, when the sap is temporarily expended in
the production of leaves. An excellent plan is, to bark the timber in the
spring and fell it in winter, by which means the sap-wood is dried up and
hardened; but as the bark of most trees is valueless, the oak tree (whose
bark is used in tanning) is almost the only one that will pay for being
thus treated.
The seasoning of timber consists in the extraction or evaporation of the
fluid parts, which are liable to decomposition on the cessation of the
growth of the tree. This is usually effected by steeping the green timber
in water, to dilute and wash out the sap as much as possible, and then
drying it thoroughly by exposure to the air in an airy situation. The
time required to season timber thoroughly in this manner will of course
much depend on the sizes of the pieces to be seasoned; but for general
purposes of carpentry, two years is the least that can be allowed, and,
in seasoning timber for the use of the Joiner, a much longer time is
usually required.
Properly seasoned timber, placed in a dry situation with a free
circulation of air round it, is very durable, and has been known to last
for several hundred years without apparent deterioration. This is not,
however, the case when exposed to moisture, which is always more or less
prejudicial to its durability.
When timber is constantly under water, the action of the water dissolves
a portion of its substance, which is made apparent by its becoming
covered with a coat of slime. If it be exposed to alternations of dryness
and moisture, as in the case of piles in tidal waters, the dissolved
parts being continually removed by evaporation and the action of the
water, new surfaces are exposed, and the wood rapidly decays.
Where timber is exposed to heat and moisture, the albumen or gelatinous
matter in the sap-wood speedily putrefies and decomposes, causing what
is called rot. The rot in timber is commonly divided into two kinds,
the _wet_ and the _dry_, but the chief difference between them is, that
where the timber is exposed to the air, the gaseous products are freely
evaporated; whilst, in a confined situation, they combine in a new
form, viz. the dry-rot fungus, which, deriving its nourishment from the
decaying timber, often grows to a length of many feet, spreading in every
direction, and insinuating its delicate fibres even through the joints of
brick walls.
In addition to the sources of decay above mentioned, timber placed in
sea water is very liable to be completely destroyed by the perforations
of the worm, unless protected by copper sheathing, the expense of which
causes it to be seldom used for this purpose.
In modern houses the labours of the Builder, the Mason, and the
Plasterer, would be of little use unless they were accompanied by that of
the Carpenter, since a very large proportion of every building consists
of the woodwork of which its interior structure is greatly composed.
As it is one of the most useful, so the Carpenter’s may be considered
the most ancient of trades, for nearly all other handicrafts require the
preparation or manufacture of the materials, but the Carpenter originally
found his materials in the forest, and at once set to work to construct
various articles from the trunks and stems of the trees best suited
for the purpose. We can only imagine one trade older than that of the
Carpenter, and that is the Tool Maker, and as the earliest tools, or at
all events some portion of them, were probably made of hard wood, the
Tool Maker may in some sense be said to have been a Carpenter also.
[Illustration: Axe. Adze.]
[Illustration: Saw. Compasses. Plumb Rule. Hammer. Square. Mallet.]
Strictly speaking, the business of the Carpenter is only with the larger
portions of buildings and the rough timber frameworks which support them,
and his principal tools are the _axe_ and the _adze_, for chopping and
roughly smoothing timbers; the _saw_, for sawing beams and planks; the
_chisel_, for making mortis holes for joining beams together, and for
cutting and paring wood; the _chalk line_, a line rubbed with chalk, and
used to make a straight line upon a board or beam, to mark the direction
in which it is to be sawn; the _plumb rule_, already described amongst
the Builder’s tools; the _level_; the _square_; the _compasses_; all of
which have been described in previous trades; the _hammer_; the _mallet_,
and various sorts of nails. The other tools represented in the engravings
belong more properly to the _Joiner_, but as the trades of the Carpenter
and the Joiner are almost always united, we will speak of all the tools
as belonging to one business. Carpenter’s work, then, consists of the
framing roofs, partitions, and floors, in making the various joints used
in beams, ties, rafters, and joists for supporting floors, and the proper
way of supporting buildings by posts and girders. The Carpenter requires
to be strong and active, that he may properly handle the heavy timbers
on which he has to work; he should have a knowledge of the science of
mechanics, that he may be able to provide for the strains and thrusts to
which the different parts of his work are exposed, and supply the proper
means of resisting them; and he should also be able to understand how
to make what are called “_working drawings_,” that he may “set out,” or
properly draw a plan of the work he has to do, from the designs of the
Architect.
The Carpenter being concerned with the portions of a building which are
made of timber, you will be better able to understand his trade by a
short description of what these are; and we will then speak a little
of the _Joiner_, whose trade is generally confounded with that of the
Carpenter.
First: Partitions, or inner divisions of a building, may be either of
brick, stone, or wood; and, in the latter case, they are generally
“framed,” or supported in a more solid framework, which should form a
portion of the main building, that is, of the outer wall; and should
be quite independent of the floors, which should not support, but be
supported by them.
Second: Flooring is formed by joists or strong beams of timber reaching
from wall to wall, where they rest upon other beams, called wall plates,
which are built into the walls themselves. The floor boards are nailed
over the upper edges of the joists, and the lower edges receive the
laths and plaster, which form the ceilings of the rooms beneath. Large
buildings are sometimes fitted with double framed floors, with two sets
of joists, and building joists resting on girders; and in superior
houses, the _wall plates_ are often supported by “corbels,” or, portions
of the timber projecting from the inside of the wall, which prevents the
necessity of opening the wall to admit the ends of the joists.
Third: Roofing consists of the roof covering, which is laid upon rafters
or slender beams, which are supported by stronger horizontal beams called
_purlins_; and these, again, rest on upright _trusses_, or strong frames
of timber, placed on the walls at regular distances from each other.
Upon the strength and firmness of these trusses, and the skill of the
carpenter’s work, depends the entire safety of the roof.
Large roofs are supported by cross beams, called _collars_, or _tie
beams_; and they are further strengthened by an upright pillar in the
centre, called a _King post_, from which slanting beams, called “struts,”
support the rafters.
We have now only spoken of common roofs, but there are many roofs of open
timber-work in churches and other public buildings, which are wonderful
specimens of the skill of the Carpenter and the Joiner. One of these,
perhaps the grandest as well as the most ancient, is that of Westminster
Hall; but there is one also in the Great Hall, at Hampton Court Palace;
and others may be seen in Churches and Halls in various parts of England.
The Joiner, as his name implies, frames and joins together the wooden
finishings and decorations of buildings, such as floors, staircases,
skirtings, door and window frames, sashes, or, the sliding parts of
windows that contain the glass, shutters, doors, chimney-pieces, &c. This
work requires much greater nicety and finish than that of the Carpenter,
and is brought to a smooth surface with the plane wherever it is likely
to be seen, while the carpenter’s work is left rough as it comes from the
saw.
The principal cutting tools used by the Joiner are, saws, planes, and
chisels.
The _saws_ are of various sizes, and are called rippers, half rippers,
hand saws, and panel saws, according to their shape, and the number of
teeth to each inch.
[Illustration: Chisel. Gouge. Screw Driver. Screw. Tenon Saw. Narrow Saw.]
The _tenon saw_ is used for cutting tenons, or flat slices from the ends
of beams, that other beams cut in the same way may rest upon them and yet
leave a flat surface. The thick back of the tenon saw keeps the blade
from “buckling,” or twisting; as it would be very likely to do while
sawing in a horizontal direction.
The _dove-tail saw_ is similar to the tenon saw, but smaller, and with
a brass back instead of an iron one. It is used for dove-tailing, or
cutting notches in a board or beam, into which projections in another
board or beam are fitted, in order that the two may be held together, as
we see the sides of a box are fitted to the back and front. Then there is
the _compass saw_, for circular work, and the _keyhole_, or _narrow saw_,
for cutting out holes.
The planes are used for bringing the edges and sides of beams, boards, or
other wooden fitting, to a perfectly smooth surface: the first of these,
used upon the rough wood, is called the _jack plane_; another is called
the _trying_ or _trueing plane_; and a third, the _smoothing plane_.
[Illustration: Trying Plane. Smoothing Plane. 2-foot Rule. Glue Pot.]
The plane, as you will see, is a solid piece of hard smooth wood, with a
hole in the centre containing the cutting tool, or, as it is called, the
plane iron, which is firmly fixed with a wedge, so that its sharp cutting
edge only slightly projects at the bottom.
The wood which is to be smoothed is fixed on the joiner’s bench by means
of a screwed board, called a shooting board, and, by means of the handle
at the top, the plane is made to slide swiftly along its surface, so that
the edge of the tool cuts off a thin shaving.
There are various sorts of planes besides these, used for cutting various
parts of the work, but they are most of them of similar construction.
Chisels are either for paring the wood, and are used with the hand; or
are intended to cut into the thickness of the wood, and are then struck
with a large wooden hammer, called the _mallet_. The _gouge_ is a curved
chisel, used for cutting mouldings or making round edges.
[Illustration: Clout Nail. Cut Clasp Nail. Brad. Spike Nail. Bradawl.
Chisel. Gimlet.]
The boring tools are the bradawl, the gimlet, and the stock and bit.
The _bradawl_ is a small sharp wire fixed in a handle, and used for
making holes to receive large nails, which, if driven in at once by
the _hammer_, would split the wood. Nails are of various kinds, the
difference in which may be seen in the engraving. The best kinds of
nails are made from thin bar iron, pointed, cut off to the proper length,
and the head formed by stamping.
The _gimlet_ is a hollow blade with a screw at the end, and fixed to a
cross handle. It is used for boring a larger and rougher hole than the
bradawl, for receiving _screws_, which are screwed into their place by
the _screw driver_, a sort of chisel, the edge or point of which enters
the notch in the head of the screw, so that the workman may turn it round.
The _bit_ is a tool not unlike a large bradawl, which fits into a stock
or handle. The bits are of various sizes, and are used for boring large
holes.
[Illustration: Centre Bit.]
The _brace and bit_, or _centre bit_, is a tool with a centre and two
sharp points, one on each side; it is placed in a bow-shaped stock with a
round loose end. This loose end the workman holds firmly, while he places
the point of the tool against the wood required to be bored; he then
turns the bow briskly round, and the two points revolving rapidly, cut
out a circular piece.
The _pincers_ are used for removing nails from wood, and it is easy to
see how they are applied. There are some other tools which belong to the
trade of the Joiner, but they are used less frequently, and a description
of them will be given when we have to say something of the trade of the
Cabinet Maker, whose work resembles the finer part of that which the
Joiner does at his own workshop.
The bench (_see large cut_) is the great table of thick planks supported
on a timber frame, at which the Joiner works; it is furnished with a
“side-board” perforated with holes to receive a pin, against which one
end of the wood on which he is operating rests, the other being firmly
fixed in the bench screw.
[Illustration: Pincers.]
[Illustration]