Carpentry for Boys
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J. S. Zerbe >> Carpentry for Boys
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[Illustration: _Fig. 293. Spur Tenon._]
[Illustration: _Fig. 294. Saddle Joints._]
BRIDLE JOINTS.--This is a form of joint where permanency is not desired,
and where it is necessary to readily seat or unseat the vertical timber.
It is also obvious that the socket for the upright is of such a
character that it will not weaken it to any great extent.
SPUR TENON.--This tenon can be used in many places where the regular one
is not available. This, like the preceding, is used where the parts are
desired to be detachable, and the second form is one which is used in
many structures.
SADDLE JOINT.--This is still another manner in which a quickly
detachable joint can be constructed. The saddle may be mounted on the
main base, or cut into the base piece. An infinite variety of forms of
saddles are made, most of them being used in dock work, and for framing
of that character where large timbers are used, as in the building of
coal chutes, and the like.
[Illustration: _Fig. 295. Joggle Joints._]
[Illustration: _Fig. 296. Framing Joints._]
JOGGLE JOINT.--This joint is used almost exclusively for brace work
where great weight must be supported. The brace has a tenon, and the
end must also be so arranged that it will have a direct bearing against
the upright, which it braces and supports, or it may have two faces, as
in the second figure, which is an exceedingly strong construction.
[Illustration: _Fig. 297. Heel Joints._]
[Illustration: _Fig. 298. Stub Tenon._]
FRAMING JOINTS.--These are the simplest form in which two members are
secured together. They are used almost wholly in rafter work, and have
very few modifications. The depth of the cut, for the toe of the rafter,
depends on the load to be carried, and also on the distance the end of
the rafter is from the end of the horizontal member on which the rafter
rests.
HEEL JOINTS.--This is by far the most secure of the framing type of
joints. This, if properly made, is much better than the construction
shown in the previous illustration, but the difficulty is to make the
rafter fit into the recesses properly. This is no excuse for failure to
use, but it is on account of inability to make close fits that is
accountable for lack of use. It will be seen that in case one of the
heels rests against the recess, and the others do not, and the pressure
is great, there is a liability to tear out the entire joint.
[Illustration: _Fig. 299. Tusk Tenon._]
STUB TENON.--This is another form of tenon which is made and designed to
be used where it is in close proximity to another tenon, or where the
mortises, if made full size, will weaken the member. The long tusk can
be shortened, to suit the place where it projects, and the stub tenon on
each side of the tusk may be made very short, and one side longer than
the other if necessary.
TUSK TENON.--Two forms of tusk construction are given. Any number of
forms have been devised, all for special purposes, and designed for
different kinds of woods. These shown are particularly adapted for soft
woods, and the principal feature that is valuable lies in the fact that
they have a number of shoulders within the mortise, each of which,
necessarily adds to the strength. It should be observed that in the
construction of the tusk tenon, the greatest care must be taken to have
it fit the mortise tightly, and this has reference to the bottom and
shoulder ends as well.
[Illustration: _Fig. 300. Double Tusk Tenon._]
DOUBLE TUSK TENONS.--The distinguishing difference between this and the
preceding is in the tusk, which in this form of construction goes
through the upright member, and is held by a cross key. The double tusk
is intended for hard woods, and it is regarded as the finest, as well
as the strongest, joint known.
COGGED JOINTS.--This differs from the regular tenoning and mortising
methods, principally because the groove or recess is in the form of an
open gain. It is used where the member is to be inserted after the main
structure is put together.
[Illustration: _Fig. 301. Cogged Joints._]
[Illustration: _Fig. 302. Anchor Joint._]
ANCHOR JOINT.--This form of connection is designed for very large
timbers, and where great care must be taken in making the parts fit
together nicely, as everything depends on this. This style is never
used where the angles are less than 45 degrees, and the depth of the
gain in the timber receiving the brace is dependent on the thrust of the
brace.
[Illustration: _Fig. 303. Deep Anchor Joint._]
The Deep Anchor Joint is an extension of the tongue of the Anchor tenon,
so that it affords a greater support for the end thrust. To clearly
distinguish between this and the preceding form, it might be said that
the Anchor Joint is one designed to protect the member containing the
gains, while the Deep Anchor Joint favors the brace, by giving it a
greater power.
CHAPTER XXI
SOME MISTAKES, AND A LITTLE ADVICE IN CARPENTRY
In the mechanical arts, workers are as likely to learn from the mistakes
committed as through correct information imparted. Advice, therefore,
might be considered superfluous. But there are certain things which are
easily remembered and may be borne in mind while engaged in turning out
any work.
This chapter is not given for the purpose of calling attention to all
the errors which are so common, but merely to point out a few which the
boy will commit as he tries to carry out his work for the first time.
One of the difficult things for any one to learn, in working with wood,
is to plane the edge of a board straight and square at the same time.
This is made doubly difficult if it is desired to plane it strictly to
dimensions.
Usually before the edge is straight it is down to the proper width
desired, and it is then too late to correct any error, because further
work will make it too narrow.
The whole difficulty is in the holding of the plane. It matters not how
rigidly it is held, and how carefully it is guarded to veer it toward
one side or the other, it will be found a most difficult task.
If the fore, or finishing, plane is used, and which is the proper tool
for the purpose, the impression seems to be, that to square up the edge
and make it cut off a thicker shaving on one side than on the other,
requires that the plane should be pressed down with force, so as to make
it dig in and cut a thicker shaving.
When this is resorted to the board is liable to get out of true from end
to end. A much better plan is to put the plane on the edge of the board
true and straight. If it is too high on the edge nearest you, bring the
plane over so the inside edge is flush with the inside edge of the
board.
Then use the fingers of the left hand as a gage to keep the plane from
running over.
Now, the weight of the plane in such a condition is sufficient to take
off a thicker shaving at the high edge, and this will be done without
any effort, and will enable you to concentrate your thoughts on keeping
the plane straight with the board.
The weight of the plane will make a thicker shaving on one side than on
the other, and correct inequalities, provided you do not attempt to
force the plane.
It requires an exceedingly steady hand to hold a plane firmly for
squaring up a half-inch board. Singular as it may seem, it is almost as
difficult a job with a two-inch plank. In the case of the thin board the
plane will move laterally, unless the utmost care is exercised; in the
truing up the thick plank the constant tendency is to move the plane
along the surface at a slight diagonal, and this is sure to cause
trouble.
It only emphasizes the fact most clearly, that to do a good job the
plane must be firmly held, that it must move along the board with the
utmost precision, and that it should not be forced into the wood.
In smoothing down a board with the short smoothing plane, preparatory to
sandpapering it, the better plan is to move the plane slightly across
the grain. This will enable the bit to take hold better, and when the
sandpaper is applied the course of the movement should be across the
grain opposite the direction taken by the smoothing plane.
It is never satisfactory to draw the sandpaper directly along in the
course of the grain. Such a habit will cause the sandpaper to fill up
very rapidly, particularly with certain woods.
When gluing together joints or tenons, always wipe off the surplus glue
with warm water taken from the glue pot. If you do not follow this
advice the glue will gum up the tools and the sandpaper used to finish
the work.
Never try to work from opposite sides of a piece of material. Have a
_work side_ and a work _edge_, and make all measurements therefrom. Mark
each piece as you go along. Take a note mentally just how each piece is
to be placed, and what must be done with it.
The carpenter, above all others, must be able to carry a mental picture
of his product.
Never saw out the scribing or marking line, either in cutting or in
ripping. The lines should be obliterated by the plane, when it is being
finished, and not before.
Make it a habit to finish off the surfaces and edges true and smooth
before the ends are cut, or the mortises or tenons are made. This is one
of the most frequent mistakes. No job can be a perfect one unless your
material has been worked down to proper dimensions.
Learn to saw across a board squarely. This may be a hard thing for the
novice to do. A long, easy stroke of the saw will prevent it from
running, unless too badly set or filed, and will also enable you to hold
it more nearly square with the board.
If you find that you invariably saw "out of true," then take some sawing
lessons for your own benefit, until you can judge whether the saw is
held true or not.
It is better to saw up a half dozen boards in making the test than
commit the error while working on a job.
GLOSSARY OF WORDS USED IN TEXT OF THIS VOLUME
$Acute.$ Sharp, to the point.
$Adjuster.$ A tool which measures distances and relative spaces.
$AEsthetic.$ The theory of taste; science of the beautiful in nature and
art.
$Abstract.$ That which exists in the mind only; separate from matter; to
think of separately as a quality.
$Alligator jaws.$ A term used to designate a pair of serrated bars which
are held together in a headpiece, and capable of clamping bits between
them.
$Analyzed.$ Separated into its primitive or original parts.
$Anchor.$ Any device for holding an object in a fixed position.
$Angle dividers.$ A sort of double bevel tool so arranged that an angle
can be made at the same time on both side of a base line.
$Angularly disposed.$ Forming an angle with reference to some part or
position.
$Archivolt.$ The architectural member surrounding the curved opening of
an arch. More commonly the molding or other ornaments with which the
wall face of an arch is changed.
$Artisan.$ One trained in some mechanic's art or trade.
$Beaded.$ A piece of wood or iron having rounded creases on its
surface.
$Beam compass.$ A drawing compass in which the points are arranged to
slide on a rod, instead of being fixed on dividers.
$Belfry.$ A bell-tower, usually attached to a church.
$Bevel square.$ A handle to which is pivotally attached a blade, which
may be swung and held at any desired angle.
$Bisected.$ To divide, mark, or cut into two portions.
$Bit.$ A small tool, either for drilling, or for cutting, as a plane
iron.
$Braced collar.$ A form of roofing truss, in which the upper cross
member is supported by a pair of angled braces.
$Breast drill.$ A tool for holding boring tools, and designed to have
the head held against the breast for forcing in the boring tool.
$Bridle joint.$ A form for securing elements together which provides a
shallow depression in one member, and a chamfered member at its end to
fit therein.
$Bungalow.$ A Bengalese term; originally a thatched or tiled house or
cottage, single story, usually surrounded by a veranda.
$Bushing.$ A substance of any kind interposed, as, for instance, a
wearing surface between a mandrel and its bearing.
$Butts.$ A term applied to certain hinges, usually of the large type.
$Callipered.$ A measured portion which has its side or thickness fixed
by a finely graduated instrument.
$Cambered.$ Slightly rising in the middle portion. An upward bend, or
projection.
$Capital.$ A small head or top of a column; the head or uppermost member
of a pilaster.
$Cardinal.$ Pre-eminent, chief, main line; _Cardinal_ line is the
principal line to make calculations or measurements from.
$Centering point.$ A place for the reception of the point of an
instrument, like a compass or a dividers, or for the dead center of the
tail-stock of a lathe.
$Cheekpiece.$ A piece or pieces at right angles to another piece, either
fixed or movable, which serves as a rest or a guide.
$Chiffonier.$ A movable and ornamental closet or piece of furniture with
shelves and drawers.
$Chute.$ A channel in any material, or made of any substance, for
conveying liquids or solids.
$Circumference.$ The distance around an object.
$Circumferentially.$ Surrounding or encircling.
$Classical.$ Relating to the first class or rank, especially in
literature or art.
$Cogged.$ Having teeth, either at regular or at irregular intervals.
$Concrete.$ Expressing the thing itself specifically; also the quality;
a specific example.
$Configuration.$ Form, as depending on the relative disposition of the
parts of a thing; a shape or a figure.
$Coincide.$ To occupy the same place in space; to correspond exactly; to
agree; to concur.
$Correlation.$ A reference, as from one thing to another; the putting
together of various parts.
$Conventional.$ Something which grows out of or depends upon custom, or
is sanctioned by general usage.
$Craftsman.$ One skilled in a craft or trade.
$Curvature.$ The act of curving or being bent.
$Concentrated.$ To bring to a common center; to bring together in one
mass.
$Dado.$ A plain flat surface between a base and a surbase molding.
Sometimes a painted or encrusted skirting on interior walls.
$Depth gage.$ A tool by means of which the depths of grooves and
recesses are measured.
$Degree.$ Measure of advancement; quality; extent; a division or space.
$Discarded.$ Cast off; to reject or put away.
$Deterioration.$ To grow worse; impairing in quality.
$Depressed.$ A sunken surface or part.
$Diagrammatical.$ A drawing made to illustrate the working or the
scheme, without showing all the parts or giving their relative positions
or measurements.
$Diametrically.$ A direction toward the center or across the middle of a
figure or thing.
$Diagonal.$ A direction which is not parallel with or perpendicular to a
line.
$Dominate.$ To govern; controlling.
$Door trim.$ The hardware which is attached to a door.
$Double-roofed.$ All form of roof structure where there is an inner
frame to support the rafters.
$Drop forged.$ Metal forms which are struck up by means of heavy
hammers, in which are the molds or patterns of the article to be formed.
$Elaboration.$ Wrought with labor; finished with great care.
$Elevation.$ The act of raising from a lower to a higher degree; a
projection of a building or other object on a plane perpendicular to the
horizon.
$Elliptical.$ Having the form of an ellipse.
$Embellishment.$ The act of adorning; that which adds beauty or
elegance.
$Entablature.$ The structure which lies horizontally upon the columns.
$Equidistant.$ Being at an equal distance from a point.
$Escutcheon.$ An ornamental plate like that part about a keyhole.
$Evolve.$ To unfold or unroll; to open and expand.
$Facade.$ The front of a building; the principal front having some
architectural pretensions.
$Facing-boards.$ The finishing of the face of a wall of different
material than the main part of the wall; the wide board below the
cornice or beneath the windows.
$Factor.$ One of the elements, circumstances or influences which
contribute to produce a result.
$Fence.$ A term used to designate a metal barrier or guard on a part of
a tool.
$Fish plate.$ A pair of plates, usually placed on opposite sides of the
pieces to be secured together, and held by cross bolts.
$Flare.$ A pitch; an angle; an inclination.
$Flush.$ Unbroken, or even in surface; on a level with the adjacent
surface.
$Frog clamping screw.$ A screw which is designed to hold or adjust two
angled pieces.
$Fulcrum.$ That by which a lever is sustained, or on which a lever rests
in turning or moving a body.
$Fluting.$ The channel or channels in a body; as the grooves in a
column.
$Gain.$ A square or beveled notch or groove cut out of a girder, beam,
post or other material, at a corner.
$Gambrel.$ A roof having two different pitches, the upper much greater
than the lower.
$Geometry.$ Pertaining to that branch of mathematics which investigates
the relations, properties and measurements of solids, surfaces, lines
and angles.
$Girder.$ A main beam; a straight horizontal beam to span an opening or
carry a weight, such as the ends of floor beams.
$Glossary.$ A collection or explanation of words and passages of the
works of an author; a partial dictionary.
$Graduated.$ Cut up into steps; divided into equal parts.
$Guide stock.$ A member which is the main portion of the tool, and from
which all measurements are taken.
$Hammer beam.$ A member in a truss roof structure, at the base of the
roof proper, which consists of an inwardly projecting part, on which the
roof rests, and from which it is braced.
$Hammer-pole.$ The peon, or round end of a hammer which is used for
driving nails.
$Hemispherical.$ Pertaining to a half globe or sphere.
$Horizontal.$ On the level; at right angles to a line which points to
the center of the earth.
$Incorporated.$ United in one body.
$Index pin.$ A small movable member which is designed to limit the
movement of the operative part of a machine.
$Initial.$ To make a beginning with; the first of a series of acts or
things.
$Insulate.$ To place in a detached position; to separate from.
$Interchangeable.$ One for the other.
$Interval.$ A space between things; a void space; between two objects.
$Interest.$ To engage the attention of; to awaken or attract attention.
$Interlocking jaw.$ Two or more parts of a piece of mechanism in which
the said parts pass each other in their motions.
$Intersection.$ The point or line in which one line or surface cuts
another.
$Intervening.$ The portion between.
$Inverted.$ Turned over; to put upside down.
$Joggle-joint.$ A form of connection which has struts attached to a
pendant post.
$Joinery.$ The art or trade of joining wood.
$Kerf.$ A notch, channel or slit made in any material by cutting or
sawing.
$Kit.$ A working outfit; a collection of tools or implements.
$Level.$ A tool designed to indicate horizontal or vertical surfaces.
$Liberal.$ Not narrow or contracted.
$Lobe.$ Any projection, especially of a rounded form; the projecting
part of a cam-wheel.
$Longitudinal.$ In the direction of the length; running lengthwise.
$Lubrication.$ The system of affording oiling means to a machine or to
any article.
$Mandrel.$ The live spindle of a lathe; the revolving arbor of a
circular saw.
$Mansard.$ A type of roof structure with two pitches, one, the lower,
being very steep, and the other very flat pitch.
$Manual.$ Of or pertaining to the hand; done or made by hand.
$Marginal.$ The border or edge of an object.
$Marking gage.$ A bar on which is placed a series of points, usually
equidistant from each other.
$Matching.$ Placing tongue in one member and a corresponding groove in
another member, so that they will join each other perfectly.
$Mediaeval.$ Of or relating to the Middle Ages.
$Miter-box.$ A tool for the purpose of holding a saw true at any desired
adjustable angle.
$Miter-square.$ A tool which provides adjustment at any desired angle.
$Mullion.$ A slender bar or pier which forms the vertical division
between the lights of windows, screens, etc.; also, indoors, the main
uprights are _stiles_, and the intermediate uprights are _mullions_.
$Obliterated.$ Erased or blotted out.
$Obtuse.$ Not pointed; bent.
$Orbit.$ The path made by a heavenly body in its travel around another
body.
$Ordinate.$ The distance of any point in a curve or a straight line,
measured on a line called the _axis of ordinates,_ or on a line parallel
to it from another line, at right angles thereto, called the _axis of
abscissas_.
$Ornamentation.$ To embellish; to improve in appearance.
$Oscillate.$ To swing like a pendulum.
$Overhang.$ In a general sense that which projects out.
$Paneling.$ A sunken compartment or portion with raised margins, molded
or otherwise, as indoors, ceilings wainscoting, etc.
$Parallelogram.$ A right-lined quadrilateral figure, whose opposite
sides are parallel and, consequently, equal.
$Parallel.$ Extended in the same direction, and in all parts equally
distant.
$Perspective.$ A view; a vista; the effect of distance upon the
appearance of objects, by means of which the eye recognizes them as
being at a more or less measurable distance.
$Pivot.$ A fixed pin, or short axis, on the end of which a wheel or
other body turns.
$Pitch.$ Slope; descent; declivity, like the slope of a roof.
$Placement.$ The act of placing; in the state of being placed.
$Predominate.$ To be superior in number, strength, influence or
authority; controlling.
$Produced.$ To lengthen out; to extend.
$Prototype.$ The original; that from which later forms sprang.
$Purlin.$ A longitudinal piece of timber, under a roof, midway between
the eaves and comb, to hold the rafters.
$Rabbeting.$ The manner of cutting grooves or recesses.
$Ratchet.$ A wheel, bar, or other form of member, having teeth or
recesses.
Rebate. A rectangular, longitudinal recess or groove, cut in the corner
or edge of a body.
$Rail.$ A horizontal piece in a frame or paneling.
$Rectangular.$ Right-angled; having one or more angles of ninety
degrees; a four-sided figure having only right angles.
$Rib and collar.$ A form of roof truss in which the collar between
rafters is used as the thrust bearing for the ribs which project up from
the hammer beam.
$Router.$ A tool for cutting grooves or recesses.
$Saddle joint.$ A form of connection in which one part has a portion cut
away, resembling a saddle, and in which the part to be attached has its
end cut so as to fit the saddle thus formed.
$Scarfing.$ The cutting away of the ends of timbers to be joined, so the
two parts on lapping will unite evenly.
$Scissors beam.$ A form of truss, in which there is a pair of interior
braces formed like shears, and secured to the main rafters themselves.
$Score, Scored.$ Shear; cut; divide; also notching or marking.
$Scratch awl.$ A sharp-pointed tool, with a handle.
$Scribe.$ To cut, indent or mark with a tool, such as a knife, awl or
compass, so as to form a cutting line for the workman.
$Self-supporting.$ Held by itself; not depending upon outside aid.
$Shank.$ Usually the handle, or portion to which the handle is attached.
$Slitting gage.$ A tool which is designed to cut along a certain line
guided by an adjustable fence.
$Soffit.$ The under side of an arch.
$Solid.$ Not hollow; full of matter; having a fixed form; hard; opposed
to liquid or fluid.
$Spindle.$ A small mandrel; an arbor; a turning shaft.
$Springer.$ The post or point at which an arch rests upon its support,
and from which it seems to spring.
$Sphere.$ A body or space continued under a single surface which, in
every part, is equally distant from a point within called its center.
$Spur.$ A small part jutting from another.
$Strike plate.$ A plate serving as a keeper for a beveled latch bolt and
against which the latter strikes in closing.
$Steel Tubing.$ Pipes made from steel; tubing is measured across from
outside to outside; piping is measured on the inside.
$Step-wedge.$ A wedge having one straight edge, and the other edge
provided with a succession of steps, by means of which the piece
gradually grows wider.
$Strain, Stresses.$ To act upon in any way so as to cause change of form
or volume; as forces on a beam to bend it.
$Strut.$ Any piece of timber which runs from one timber to another, and
is used to support a part.
$Stub.$ A projecting part, usually of some defined form, and usually
designed to enter or engage with a corresponding recess in another
member.
$Submerged.$ To be buried or covered, as with a fluid; to put under.
$Swivel.$ A pivoted member, used in many forms of tools, in which one
part turns on the other.
$Tail-stock.$ The sliding support or block in a lathe, which carries the
dead spindle, or adjustable center.
$Technical.$ Of or pertaining to the useful in mechanical arts, or to
any science, business, or the like.
$Texture.$ The disposition of the several parts of any body in
connection with each other; or the manner in which the parts are united.
$Tool rest.$ That part of a lathe, or other mechanism, which supports a
tool, or holds the tool support.
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