Elementary woodwork can be more readily learned from small pieces of
wood than from large; so the exercises that are here given are of such
dimensions that they can be easily handled in working out the problems.
Since it is by what we study and learn that we are able to do something
else, the student in beginning this work should thoroughly familiarize
himself with the tools, their names and uses, so that he may more
readily understand their application in the work that follows.
The equipment for the general use of students in each bench locker is
as follows:
1 20-inch Rip-Saw.
1 20-inch Cross-Cut Saw.
1 10-inch Back-Saw.
1 8-inch Try-Square.
1 8-inch Bevel.
1 8-inch Wing Dividers.
1 Marking Knife.
1 ⅜-inch Hand Mortising Chisel.
1 Bit Brace.
1 ¼-inch, ⅜-inch, ½-inch and ¾-inch Auger Bit.
1 Nail Set.
1 Mallet.
1 Hammer.
1 Oil Stone.
1 Oil Can.
1 Screw Driver.
1 Dust Brush.
The equipment of tools in drawer and under the care of individual
students is as follows:
1 Number 5 Bailey Iron Plane (Jack-Plane).
1 Number 4 Bailey Iron Plane (Smooth-Plane).
1 Marking Gauge.
1 ¼-inch, ½-inch, ¾-inch, and 1-inch Bevel Edge Paring Chisel.
1 ¼-inch and ¾-inch Skew Turning Chisel.
1 ¼-inch and ¾-inch Turning Gouge.
Tools, such as molding, beading, rabbeting, and plow planes are found
in the tool room, and are issued to students on check when required.
[Illustration: FIG. 1.]
Fig. 1 shows the double bench equipped with rack, cam and quick acting
vises, with the locker for the general tools and four drawers on each
side of the bench with tools for the use of the individual student.
Carpenters’ benches are usually about 33 inches high, while cabinet and
pattern makers’ benches are from 2 inches to 4 inches higher.
The careful workman as a rule takes great pride in the condition
in which his bench is kept; so the beginner should see that his
immediate surroundings are kept in a neat, workmanlike manner, and with
everything in proper place.
Care should be taken to protect the top of the bench from injury; it
should never be marked by the chisel or cut by the saw. If chiseling
has to be done on the bench, place the work on the bench hook or on a
board, and in sawing use a bench hook such as is shown in Fig. 2, that
has a side lip that will protect the bench top.
[Illustration: FIG. 2.]
The bench hook is made by students as an exercise, and is used to
replace those hooks that have become worn out.
The material, which is delivered from the lumber yard in boards or
planks, has to be cut up into lengths and widths suitable for the work
to be done. The tools used for doing this cutting are the rip-saw and
the cross-cut saw.
Now, a great amount of time can be lost in this work by the student,
for the reason of his trying to do work with one tool when another
should be used, and especially is this so in regard to saws. A saw
will cut faster than a chisel in some places, and sometimes make the
work as good if not better; so the student should learn to file and to
keep a saw in just as good order as any other tool used.
We devote considerable space here to the saw, for we feel that the saw
as one of the principal tools is often neglected, and is not used by
students in their work as much as it should be. By a judicious use of
this tool much time can be saved and a greater amount of ground covered
than by trying to use a chisel or a jack knife in its stead.
Saws are either reciprocating or continuous in action; the first being
a flat blade and a practically straight edge, making a plane cut, as
in mill, jig, and sash saws; the latter either a circular or rotating
disc, cutting in a plane at right angles to its axis (see buzz-saw in
shop) or a continuous ribbon or band running on two pulleys, making
a plane or curved cut with a straight edge parallel to their axis of
rotation (see band-saw in shop).
Practically speaking, the teeth are a series of knives set on a
circular or straight line, each tooth cutting out its proportion of
wood, and kept from cutting more by the teeth on either side of it.
Each tooth should cut the same amount and carry out the chips or dust,
dropping it to the side or below the material being sawed. Different
kinds of woods require teeth different in number, angle or pitch, and
style of filing.
The perfect saw is one that cuts the fastest and smoothest with the
least expenditure of power; to do this it is evident that each tooth
should be so constructed and dressed as to do an equal proportion of
the work, for if any of the teeth are out of line or shape they are not
only useless themselves but a disadvantage to the others.
A saw tooth has two functions—paring and scraping. A slitting or rip
saw for wood should have its cutting edge at about right angles to the
fibre of the wood, severing it in one place, the throat of the tooth
wedging out the piece.
[Illustration: FIG. 3.]
The rip-saw, Fig. 3, should be filed square across, and the front or
rake of tooth should be at about right angles to the edge of the saw.
After jointing and setting, file one half the teeth from each side,
which will give to the cutting edge of the tooth the slight bevel
it should have for soft wood; for medium hard woods use a finer
toothed saw, and file in the same manner; for the very hard, tough
and cross-grained woods, use a saw still finer with the teeth filed
slightly beveling, as ripping cross-grained stuff partakes a little of
the nature of cross-cutting.
In all cases where ripping is done, the thrust of a saw should be on
an angle of about 45 degrees to the material being cut, as shown in
Fig. 4. This makes a shearing cut, an advantage that can be quickly
demonstrated with an ordinary pocket knife, cutting any piece of soft
wood.
Saws are designated by the number of points or teeth per inch, and the
selection of a saw depends upon the character of wood to be worked. A
rip-saw should have from 4 to 10 teeth per inch, the cross-cut saw from
6 to 16 teeth per inch. This includes the back-saw, it being filed the
same as a regular cross-cut saw.
[Illustration: FIG. 4.]
[Illustration: FIG. 5.]
The harder the wood, the greater the number of teeth the saw should
have.
We will now consider the cross-cut saw tooth in regard to rake or
pitch; this being one of the most important features, too much care
cannot be taken to have the correct amount of pitch for the duty
required. To illustrate this. Fig. 5 represents a board, across which
we wish to make a deep mark or score with the point of a knife.
Suppose we hold the knife nearly perpendicular as at B; it is evident
that it will push harder and will not cut as smoothly as if it were
inclined forward as at A. It follows then that the cutting edge of a
cross-cut saw should incline forward as at C, Fig. 6, rather than stand
perpendicular as at D, Fig. 7.
[Illustration: FIG. 6.]
[Illustration: FIG. 7.]
Too much hook or pitch and too heavy a set are very common faults, not
only detrimental to good work but ruinous to the saw; in the first
case, by having a large amount of pitch, the saw takes hold so keenly
that frequently it “hangs up” suddenly in the thrust—the result, a
kinked or broken blade; in the second, by having too much set, the
strain caused by the additional and unnecessary amount of set is out of
proportion to the strength of the blade, and it is broken in the same
manner. The most general value of pitch used is 60 degrees, though this
may be varied a little, more or less, to advantage, as occasion may
demand.
In all cases the size of tooth depends largely upon the duty required;
a long tooth has the demerit of being weak and liable to spring, but
the merit of giving a greater clearance to the saw-dust. The throat
space in front of each tooth must be large enough to contain the dust
of that tooth from one stroke; the greater the feed the deeper the dust
chamber required, or the more teeth. Where the teeth are fine the shape
of the throat is of special interest.
The teeth of a hand-saw should be filed so true that on holding it up
to the eye and looking along its edge, it will show a central groove
down which a fine needle will slide freely the entire length. This
groove must be angular in shape and equal on each side, or the saw is
not filed properly and will not run true.
[Illustration: FIG. 8.]
[Illustration: FIG. 9.]
[Illustration: FIG. 10.]
[Illustration: FIG. 11.]
Fig. 8 shows how the groove should appear on looking down the edge of
the saw. The action should be such that the bottom of the cut or kerf
will present the appearance as shown in Fig. 9, and not as in Fig. 10;
the cutting action is shown in Fig. 11, the cutting being done with the
outside of the tooth; the fibre of the wood is severed in two places,
and the wood is crumbled out from point to point by the thrust of the
saw.
The proper amount of bevel is very important, as is demonstrated by the
above figures, for if too much bevel is given the points will score
so deeply that the fibres severed from the main body will not crumble
out as severed but will be removed by continued rasping. This is true,
particularly in hard woods, as they require less bevel, as well as
pitch, than soft wood.
The next point to be considered is the bevel or fleam of the point. In
Fig. 12 the filer, as in all cases, files from the heel to the point;
which is the only correct way.
[Illustration: FIG. 12.]
The file is supposed to be perpendicular to the side of the saw in the
vertical plane (see Fig. 13), at an angle of about 45 degrees in the
horizontal plane, measuring from file line towards heel (see Fig. 14).
[Illustration: FIG. 13.]
Fig. 15 is a fair representation of many saws that we have seen owned
by workmen; the result of owning such tools is shown in the poor work
turned out by them.
[Illustration: FIG. 14.]
As has already been said, the filing should be done from the heel of
the saw toward the point. Many practical saw filers contend that this
is wrong; that the filing should be done from the point of the saw
toward the handle; but the only support they offer for this theory
is that they do away with the feather edge that the filing from the
heel of saws puts on the cutting face of the tooth. The feather edge
is no objection, as the main part of it is removed when the teeth are
side-dressed after the saw is set and sharpened.
Against the correctness of filing from point to handle may be cited the
following objections:
Where a different angle of back is required (it should be remembered
that that angle of face should be the same in nearly all cross-cut
hand saws, and that angle of back governs angle of point) it will be
found very difficult to obtain it without changing the angle of face
of the tooth, and as the cutting duty is on the long side of the face,
any change is, of course, of great influence. Again, to file from the
point of the saw it is necessary to file with the teeth bent toward the
operator. This will cause the saw to vibrate or chatter, a thing which
not only renders good, clean, even filing impossible, but breaks the
teeth off the file.
[Illustration: FIG. 15.]
The setting of a saw is an important part of the work in keeping a saw
in order, and should be done AFTER the saw has been JOINTED, and before
filing.
The set should be uniform throughout, as the good working of a saw
depends nearly as much on this as on the filing. One great mistake is
often made in setting a saw, and that is that many try to put the set
in the blade instead of in the tooth. The set should not go at the most
lower than half the length of the tooth; by going lower it is liable to
spring the body of the saw, if not break the tooth out.
Two methods may be given for setting saws. The first, or old method
(employed before saw-sets were invented, and still used by old
mechanics) is to take a hardwood block, lay the saw on it, and with a
nail set and hammer set every other tooth on the side, then turn the
blade over and repeat the operation on the teeth missed from the first
side. It is needless to make any comment on this method when saw sets
can be bought that are absolutely reliable in their operation.
The second method is to use the saw-set. Saw-sets are made in many
styles, and can be bought at any hardware store.
[Illustration: FIG. 16.]
[Illustration: FIG. 17.]
Figs. 16 and 17 show two styles of saw-sets; much might be said in
favor of each.
Saw clamps or vises used to hold the saw when filing can be bought (see
Fig. 18), but a simple homemade vise can be put together by means of
two pieces of board, one 3 feet 6 inches long and 6 inches wide, and
one 2 feet 4 inches long and 6 inches wide. By fastening a piece 2½
inches thick about 10 inches from the top of each, to act as a fulcrum,
and fastening a piece on each board at the top to act as jaws, and
using a wedge at the bottom to tighten it up, a very serviceable vise
is obtained (see Fig. 19).
[Illustration: FIG. 18.]
[Illustration: FIG. 19.]
To assist those not skilled in the art of filing, there is made a
saw-filing clamp with a guide, of which a cut is here shown in Fig. 20.
A few general rules may be observed in saw-filing: See that the file
is held at the same angle throughout the operation. File every other
tooth on one side, and when filed, reverse the saw and file the other
teeth from the other side. For rip saws, place the file at right angles
with the saw, and file the rake of tooth at right angles to the edge.
After a saw is properly set and filed, lay it on a flat board and rub
over the points of the teeth on the sides with an oil stone; this will
regulate the set and insure smooth cutting, making the filing last
longer. Should the saw not run true take another cut with the oil stone
over the side toward which it leads.
[Illustration: FIG. 20.]
A fast cutting cross-cut saw should have deep teeth.
Much useful information on saws can be obtained from a small book
published and issued by Disston & Sons, Philadelphia, entitled “Hand
Book for Lumbermen,” which, I believe, can be obtained on application.
The other tools used in this course will be taken up in order as they
are used in the work.