The joints shown in the following
illustrations are such as are mostly employed in framed
woodwork, and although they do not cover the whole ground, or
show all the styles and methods of framing known to the expert
workman, they include nearly all of the principal joints in
general use, both in light and heavy framing; later on I may
show other joints and splices that are not included in the
figures shown in this portion of the work.
introduction of steel in the construction of buildings has in a
great measure displaced woodwork in the erection of large
buildings in towns and cities, yet timber working is still of
sufficient importance to warrant a careful study of the
properties of wood and its uses, hence the following
descriptions of various woods are offered in order that the
worker may have a more or less intelligent idea of the nature of
the materials he is manipulating.
This short treatise it is hoped
will be found useful, interesting and instructive to the reader,
and while it is not intended to be exhaustive, it may be
depended upon to be reliable as far as it goes.
All trees are divided by into three classes; Exogens, or outward-growers; Endogens, or
inward-growers; and Ecrogens, or summit growers - according to
the relative position in which the new material for increasing
the substance of the tree is added.
Typical trees of each class
would be the oak, the palm, and the tree fern. We have to deal
with the exogenous class only, as that furnishes the timber in
general use for construction, the term "timber" including all
varieties of wood which, when felled and seasoned, are suitable
for building purposes.
If the stem of an exogenous tree be
cut across, it will be found to exhibit a number of nearly
concentric rings, more or less distinct; and, in certain cases,
radial lines intersecting them. These rings represent the annual
growth of the tree which takes place just under the bark.
ring consists of bundles of woody fiber or vascular tissue, in
the form of long tapering tubes, interlaced and breaking joint
with each other, having a small portion of cellular tissue at
intervals. Towards the outer edge of each ring the woody fiber
is harder, more compact, and of a darker color than the
As the tree advances in
age, the rings and rays become more irregular, the growth being
more vigorous on the sunny side, causing distortion. The
strength of wood "along the grain" depends on the tenacity of
the walls of the fibers and cells, while the strength "across
the grain" depends on the adhesion of the sides of the tubes and
cells to each other.
FRED T. HODGSON