The following operations are designed to give the student a TRAINING
in the use and care of the most commonly used carpenters’ and joiners’
tools. It is not intended that the student will be able to finish
each exercise in one trial, as mistakes will be very common at the
beginning, and it is advised that at least two or three trials may be
given for the practice and training involved.
In Fig. 21 is shown the working drawing (mechanical drawing) of a
rectangular block of wood, and before we proceed to do the work
required to finish this, we will study the drawing.
In order to represent solid figures with their three dimensions,
length, breadth, and thickness, on a plane surface, i.e., a sheet
of paper, we must have at least two drawings (projections), but to
simplify the reading still further a third drawing is given, sometimes
with additional drawings in the form of cross-sections.
To understand fully the principle upon which a working drawing is made,
we will suppose that two transparent planes cross each other at right
angles, making four right angles as shown in Fig. 22, (these angles
to be known as the 1st, 2nd, 3rd, and 4th angle of the co-ordinate
planes), and respectively called the Horizontal and the Vertical
planes.
[Illustration: FIG. 21.]
Two of these angles are used in practice, the 1st and the 3rd; the most
modern practice is to use the 3rd, although the 1st is still used in
some manufacturing establishments and by some teachers.
[Illustration: FIG. 22.]
We will take, first, the 1st angle, and compare it with the results
obtained from the 3rd angle. We place the solid (exercise 1) in space
in the 1st angle, and also place a similar one in the 3rd angle (see
Figs. 23 and 24).
[Illustration: FIG. 23.]
[Illustration: FIG. 24.]
By projecting the lines back on the vertical, and down on the
horizontal plane, we obtain two views which are respectively the
elevation on the vertical and the plan on the horizontal plane; to
obtain the third view or end elevation, we have another plane placed
perpendicular to planes H and V, as shown in Figs. 23 and 24, and the
lines projected back from the left end; by opening or revolving these
planes into one plane, as shown in Fig. 25, we have a working drawing
made in the 1st angle.
[Illustration: FIG. 25.]
Referring to Fig. 24, where we placed the solid in the 3rd angle, we
project the lines up on the horizontal and to the front on the vertical
plane, and by placing another plane at the end, perpendicular to the
H and V planes, we obtain the third projection. Revolving the planes
into one plane (i. e., a sheet of paper) Fig. 26, we have the working
drawing in the third angle. Compare the results obtained, and note the
difference in the reading of the drawing.
In the first angle we see the plan is below the elevation, and in the
third angle the plan is above; the pieces cut out of the exercise may
also be noted in the end projection by the lines passing through the
center of the exercise; in the first angle the line comes out full, the
end being exposed, and in the third angle the surface is behind the
full end and shows a dotted line.
Lines that are seen are shown as full lines.
[Illustration: FIG. 26.]
Lines that are below a surface and are required in the reading of a
drawing are shown as dotted lines.
The drawing, Fig. 21, calls for a piece that is 8 inches at its
longest, 2 inches at its widest, and 1 inch at its thickest point,
and that may be designated thus: piece 8 inches × 2 inches × 1 inch
finished.
For measuring, a standard rule 2 feet long that can be folded up is
preferred. The rule is divided into feet, inches, ½ inches, ¼ inches,
⅛ inches, ¹/₁₆ inches, etc. On some rules will be found scales that
can be used in measuring drawings that are drawn to scale. The drawing
may be of any scale, using ⅛, ¼, 1, 1½, 3, or 6 inches to the foot.
[Illustration: FIG. 27.]
The first thing to be done toward carrying out the work is to saw out
a piece from the plank that is laid on the saw trestles (Fig. 27).
Mark with a pencil the lines to be sawed; holding the rule in the left
hand, and the pencil in the right, and placing the index finger of the
left hand against the edge of the plank, as shown in Fig. 28, draw both
hands toward the body, thus marking out the piece lengthwise; then
measure the length required and place the try-square (Fig. 29) against
the edge of the plank, and draw a line along the blade through the
point marked.
The piece should be marked out larger than the finished exercise so
that there will be stock enough in the piece to perform the operations
required, say 8½ inches × 2½ inches, the plank being thick enough to
provide for the work on the sides.
[Illustration: FIG. 28.]
Having “laid out” the piece on the plank, take the rip-saw and hold it
as shown in Fig. 30: saw down the line, taking care that the “kerf” is
square to the side of the plank; then take the cross-cut saw, and saw
across the line marked. Hold the cross-cut saw as in Fig. 30.
After having cut the piece from the plank take the jack-plane and put
it in good condition for work. A sectional view of the Bailey Iron
Plane is shown in Fig. 31, and the parts are as follows:
A—Plane-Iron.
B—Cap Iron.
C—The Iron Lever.
D—Thumb piece and Cam.
E—Screw which acts as a fulcrum when the thumb piece is pushed
into position.
F—Thumb screw by which the Plane-Iron A is regulated for any
thickness of shaving.
G—Lever which is in contact with Plane-Iron.
H—Screw which holds the iron bed piece in place.
I—Bed piece.
K—Lever.
[Illustration: FIG. 29.]
The plane-iron should be ground on the grindstone if nicked or rounded.
To grind the plane-iron it should be held in the hand as shown in Fig.
32.
[Illustration: FIG. 30.]
[Illustration: FIG. 31.]
Apply the iron to the stone, as indicated by dotted line A, Fig. 33;
then raise it until the proper angle is reached, a position indicated
by full lines B.
[Illustration: FIG. 32.]
Move the tool gradually from one side of the stone to the other. See
that there is plenty of water on the stone. The tool should be held
during the operation so that it revolves toward the person grinding.
The tool thus held is not so liable to have a “wire edge” as it is if
held on the stone while it is revolving away from the operator.
[Illustration: FIG. 33.]
The “whetted” edge should never be ground away unless the plane-iron is
in very poor condition.
The grinding is complete when the bevel reaches the cutting edge,—a
condition which can readily be determined by holding the finger along
the flat side of the iron and having the light fall in the proper
direction; a thin bright line will be seen which will determine whether
the iron is ground enough. The plane-iron is shown before it is ground
in Fig. 34, and Fig. 35 shows it after it is ground.
[Illustration: FIG. 34.]
[Illustration: FIG. 35.]
[Illustration: FIG. 36.]
To whet or sharpen the iron an oil stone is used. Oil stones are of
different grades; a stone of medium hardness is best, as it will cut a
little faster and leave a fairly smooth edge; whereas if the stone be
hard much time is required to whet the iron, but it leaves a smoother
edge. A coarse stone leaves a rough edge. Use oil that will not become
gummy on the stone. Several good artificial stones have lately come on
the market which give good service. To sharpen the iron, apply it as
shown in Fig. 36, 1 and 2, and move it back and forth as indicated in
Fig. 37.
[Illustration: FIG. 37.]
Many persons sharpen their plane irons as indicated in Fig. 38; at
first thought this may appear to be right, but many mechanics of long
experience sharpen the “iron” as indicated in Fig. 36. This method
gives a stronger edge, which is not so liable to get nicked when the
iron strikes a knot or a hard spot in the work.
[Illustration: FIG. 38.]
Great care should be taken to avoid giving the iron a rocking motion on
the oil stone, as this will round the edge and the iron will not be any
sharper than it would be if it were in the form shown in Fig. 39.
[Illustration: FIG. 39.]
[Illustration: FIG. 40.]
After having whetted the bevel side of the iron sufficiently, turn the
iron so that it will rest perfectly flat on the stone, as shown at
3, Fig. 36, and whet it in this position; this will remove the “wire
edge.” Care should be taken to see that the iron is not raised in
whetting the flat side; if raised as in Fig. 40 the cutting qualities
of the edge will be injured.
The iron is now sharpened. Replace the cap iron, keeping it back
from ¹/₆₄ to ¹/₃₂ of an inch from the cutting edge; then place it
in position and fasten it; look down the face of the plane and see
that the edge protrudes far enough to cut the required thickness. The
adjustments are made by the thumb screw F and lever K, Fig. 31.
[Illustration: FIG. 41.]
Place the block already sawed on the bench against the bench stop, Fig.
41, and then follow the method here given for planing a piece to the
given dimensions.