Having prepared Harry for the serious work to come by his explanation
of the plane and its operation, Ralph prepared to start his pupil on
the most important and difficult problem in shopwork--squaring up stock.
"Anybody," he said "can hack away at a piece of wood with tools, and
get some kind of result, but if this work is worth doing at all, it
is worth doing well, and to be able to square up stock is perhaps the
most important operation you will ever do. It is like mathematics, the
answer is either right or wrong. When you finish, the stock is either
square or not square.
"To square up stock means to reduce it to three definite dimensions,
length, breadth, and thickness, with all adjoining edges or surfaces at
right angles. It sounds easy.
"Suppose we want a piece 12 inches × 2 inches × 7/8 inch. First, saw
out your stock about 12-1/4 inches × 2-1/4 inches × 1 inch. This allows
something each way for the tools to remove in the process--for sawdust
and shavings. It is considerably more than necessary, but on the first
trial you waste more than later, when you have become skilled in this
work.
"Second. Dress down one of the flat faces with the jack plane; follow
with the smoothing plane and test, with straight edge, with the grain,
across it, and diagonally across corners. When this face is finished it
constitutes the foundation of the process, and is called the 'working
face.'
"Third. Make a pencil mark on the working face near one of the edges.
This is called a witness mark, and it indicates that the edge it
touches is to be the next face dressed.
"Fourth. Dress down the edge, making it square with the working face,
and testing its whole length with the try square. This is the 'joint
edge' (Fig. 116).
"Fifth. Set the marking gauge, as shown in Fig. 117, holding it in the
left hand and the rule in the right, to two inches, the width of the
finished piece. The reason for this is that the scale on the gauge
stick is sometimes inaccurate.
"With the gauge block against the joint edge, gauge a line the entire
length of the working face. In doing this, the gauge may be used in
either hand, and in fact it is well to practise so as to be able to
use either at will. The tool should always be pushed from you, and at
the same time tilted from you, until the steel point makes only a fine
line. If it is held upright, the point will try to follow the grain,
which is very seldom parallel with the edge.
[Illustration: Fig. 116. Steps in the process of squaring up stock]
"You have now laid out on the working face your first dimension--the
width.
"Sixth. Plane down the edge opposite to the joint edge, almost to the
gauge line just drawn. Remember that the tendency is always to take off
too much, and when a piece is too small there is no way of making it
larger, but if it is left a little too large, it is a simple matter to
take off one more shaving. In other words, always be on the safe side,
and take off too little rather than too much. Test this edge to see
that it is square with working face before reaching the gauge line. Get
into the habit of marking all high spots with a pencil, and planing out
the marks.
[Illustration: Fig. 117. "Setting" the marking gauge]
"Seventh. Set the gauge at the required thickness, in this case 7/8
inch--and with gauge block against working face, make a line full
length on both of the squared edges.
"Eighth. Dress down the remaining rough face to or near both gauge
lines just drawn, and test with straight edge, as in the working face.
The stock is now to the second dimension--thickness.
"Ninth. Secure the last dimension--length. As near one end as possible
make a line across the working face with a knife and try square, and
continue it around the four sides back to the starting place. If it
does not come out exactly at this point, the stock is not square.
"From this knife line, measure off the length on the working face, and
square a knife line on the four sides, as on the first end. Block-plane
both ends to the knife lines, and test.
"If these nine successive steps are carried out accurately, the answer
is correct," as Ralph remarked after Harry had worked faithfully
throughout the whole explanation.
The boys realized that they needed a shooting board as a necessary part
of their equipment, and after Ralph had worked out the drawing shown in
Fig. 118, Harry was told to square up the four pieces of stock to be
used in its construction.
[Illustration: Fig. 118. The shooting board]
"Now let me show you a new trick," said Ralph. "It is always a good
plan after making a drawing to write out a bill of material something
like this:
1 pc. pine 14 × 8 × 1/2 1 pc. pine 6 × 2 × 1/2
1 pc. maple 14 × 6 × 1/2 4 1-1/4-inch f. h. screws
1 pc. pine 8 × 1-1/2 × 7/8 5 3/4-inch f. h. screws
"There you have in a nutshell all the items needed for the shooting
board, and you can proceed to square all your pieces to these
dimensions without consulting the drawing until you are ready to
assemble the parts. The five 3/4-inch screws are for fastening the
maple pieces to the flat piece of pine, and the 1-1/4 screws to fasten
the cleats. All the holes for screws are to be bored and countersunk."
"What's countersunk?" asked Harry.
This led to a talk on screws and boring tools, and as it is valuable to
the young worker in wood, we will give it as fully as possible.
[Illustration: Fig. 119. The use of screws]
"There are several kinds of screws," began Ralph, "but the two most
commonly used are flat heads and round heads. (Fig. 119). Flat-head
screws are those we generally think of, but unless the hole which has
been bored or drilled is reamed out at the top, countersunk as we call
it, the screw head will stand out from the surface ready to tear your
clothes and to scratch anything it may come in contact with, so you can
readily see the importance of sinking them below the surface.
"On the other hand, there are often cases where we have no desire to
hide the screw. The round heads are used for such cases, and because of
their shape they do not catch hold of things. These screws are usually
blued--treated with acid to give them a dull, more artistic colour.
Screws treated in this way do not rust as readily as the bright ones.
You can buy brass screws in both flat and round head forms; in fact you
can get tinned, Japanned, lacquered, bronzed, copper, nickel, and even
silver plated screws--if you have the money.
"In buying them, you must always give two numbers--the length, in
inches, and the diameter. This is the diameter of the wire forming the
body and runs from 0 to 30, number 0 being about 1/16 inch.
"A one-inch screw No. 8 would be fatter or larger in diameter than a
one-inch No. 6, which is of comparatively slight or thin proportions.
They are sold in boxes containing a gross.
"In fastening two pieces of wood together, they should be prepared as
shown at _a_ (Fig. 119) for a flat head and as at _b_ for a round head.
The screw slips through the first board, and the screw threads engage
only in the second in each case."