in making chasers, as shown in Fig. 3, the difference between this hub
and the other one referred to, is that the thread has one straight
side corresponding with the radial side of the tooth. The blank from
which the saw is made is placed on a stud projecting from a handle
made specially for the purpose, and having a rounded end which
supports the edge of the blank, as the teeth are formed by the cutters
on the hub.

The saw, after the teeth are formed, may be hardened and tempered by
heating it slowly until it attains a cherry red, and plunging it
straight down edgewise into cool, clean water. On removing it from the
water it should be dried, and cleaned with a piece of emery paper, and
its temper drawn to a purple, over a Bunsen gas flame, over the flame
of an alcohol lamp, or over a hot plate of iron. The small saw shown
in Fig. 4 is easily made from a rod of fine steel. It is very useful
for slotting sheet brass and tubes, slotting small shafts, nicking
screws, etc. Being quite small it has the advantage of having few
teeth to keep in order, and it may be made harder than those of larger
diameter. A series of them, varying in diameter from one eighth to
three eighths of an inch, and varying considerably in thickness, will
be found very convenient.

These cutters or saws, with the exception of the smaller one, may be
used to the best advantage in connection with a saw table, like that
shown in Fig. 8. This is a plane iron table having a longitudinal
groove in its face to receive the guiding rib of the carriage, shown
in Fig. 9, and a transverse groove running half way across, to receive
a slitting gauge, as shown in Fig. 8. The table is supported by a
standard or shank, which fits into the tool-rest socket. The saw
mandrel is supported between the centers of the lathe, and the saw