TOOL TEMPERING, ETC.
The great object is to harden at as low a heat as possible, so as not
to injure the steel. The tool must not be treated as a blacksmith does
iron, nothing like so hot, but so as to be of a dull cherry color.
Steel that will not harden at this heat is poor stock. When so heated,
plunge it into cold water. This will make the tool hard and brittle,
like glass, so that it is not fit to cut with; you must then rub it
bright on a piece of emery paper or a grindstone, and hold it in the
fire for a second or so at a time, until the temper is drawn to the
right degree of toughness and tenacity. This will be, for turning-tools
for _hard_ wood, of a dull blue-brown, say violet, color. Straw brown
is hard enough to cut steel, and you do not want such a temper for wood
in general, but for some purposes, it is desirable to have a very hard
tool. When the edge _crumbles_, it is too hard, and must be lowered in
temper; when it rounds over, or dulls quickly, it is too soft, and
needs to be hardened. This much in the way of tools of which more will
be said hereafter.
Many things are not held in the centers at all, but are grasped by
chucks, of different patterns or shapes. This, to me, is the most
satisfactory way of turning, inasmuch as it allows perfect liberty and
sweep in all directions, and does not restrict the fancy or imagination
of the workman.
[Illustration: Fig. 57.]
[Illustration: Fig. 58.]
It is not necessary to mention _what_ kinds of work can be done, for
that will occur to every one, but I will merely give here an
illustration of the facility which the chuck affords for all kinds of
work. Fig. 57 is a box cover, and being held at first by the corners,
permits the inside to be turned out to fit the bottom. Afterwards,
whatever finish or pattern is desired, can be given to the top. There
is in every lathe, a center screw, like Fig. 58, which is useful for
holding work that has, or is to have, a hole in it, but for fine work
it is not suitable, for the obvious reason that the screw spoils it.
Fig. 57 is the scroll chuck, and is a favorite instrument of mine. I
could dispense with many things—the face-plate of the lathe for
one—better than I could with this. If I want to make a sleeve-button,
there is my friend, the scroll chuck, ready to hold the piece true to
the center, without any adjustment whatever and hold it firmly, too. If
I wish to bore out a ring, the chuck will grasp true, and hold it
without spring: in fact, not to dilate unnecessarily, I call it the one
thing no turner can afford to be without. There are many in the market,
but the best one for general work of this class, I have found to be
that made by A. F. Cushman, of Hartford, Connecticut. He makes a very
small chuck, also, for holding drills, that is exceedingly convenient
for them, and for holding screw wire, or any work of that class. The
“Beach Chuck,” made by the Morse Twist Drill Company of New Bedford,
Massachusetts, is also a good chuck, but as I am not now discussing the
merits of chucks, I will return to the subject in hand—treatment of
woods.
I do not design, in this little work, telling any one how to hold a
tool, for it is to be presumed that at least that part of the craft has
been acquired. Even if I did essay to tell them, I could no more impart
such knowledge than one could skate by seeing another person do it.
Observation and practice are the only teachers.