66 
THE YOUNG SCIENTIST. 
and the fret saw, which, had previously 
been heated at the ends and turned over, 
was inserted in the grooves, and the ten- 
sion on the bow kept the saw taut. This 
little device did excellent work, and was 
easily adjusted, as the saw could be in- 
stantly removed by simply bending the 
bow. 
Fig. 2 will convey an idea as to how the 
saw was formed. It will be seen that the 
fret saw forms the string, as it were, of an 
Fi,^. 2. 
ordinary bow. A little ingenuity displayed 
in this direction, and the expenditure of a 
few cents for saws, will enable any boy to 
make a saw frame like the one just de- 
scribed, and when once in possession of a 
saw capable of doing good work, it will 
not be saying much for the owner's intel- 
ligence and industry, if he does not soon 
make it earn money enough to purchase 
a good foot-power machine. 
Fig. 3 shows another style of a Jiome- 
made saw frame, which can be constructed 
at small cost by any one who can use car- 
penter's tools. The jaws, o o, are made of 
Fig. 3. 
dry, straight-grained beech or maple, and 
are about twenty inches in length, and 
one inch square. They require to be made 
tapering toward the ends, as shown in 
the drawing, the ends near the saw being 
finished to about half an inch square, and 
the other end finishing up to about three- 
quarters of an inch square. At the point 
where the stretcher is mortised into the 
jaws, the latter should be left the full size 
of the wood, for it i'S there where the 
greatest strain exists, and the jaws will be 
weakened somewhat by the mortises being 
made in them. The jaws should be 
rounded off or chamfered a little to the 
outside of the frame from end to end, as 
it makes the frame look so much neater 
and workmanlike. 
The next thing will be to make the 
stretcher, which should be about nine 
inches long and one inch square. A piece 
of straight-grained pine is good enough 
for this purpose, as it has not much strain 
to resist. Cut tenons on each end, as 
shown in Fig. 4, about half an inch long, 
and three-eighths of an inch thick. Cut 
Fig. 4. 
out the sides with a spokeshave, same as 
shown, then mortise the jaws, to receive 
the tenons on the stretcher, about five 
inches from the tail ends, and see that the 
tenons fit nice and snug, but not too tight. 
It is very important that this part of the 
work should be well done, for if there is 
any lost motion crosswise of the saw, 
it will be very difficult to make it cut 
straight. 
Notch the jaws at the tail ends on the 
outside edges, to receive a cord, as 
shown at s, in Fig. 3. The use of 
the cord is easily understood ; the slat 
of wood that runs through it is about 
three-quarters of an inch wide, and 
about one-quarter of an inch thick. 
In tightening up the cord, the slat 
will require to be pushed up until 
there is room enough for it to pass 
the stretcher, when the saw can be 
made taut, after which the slat can 
be slipped down until it assumes the 
position shown in Fig. 3. 
The next thing will be to make a 
neat handle, which can be done as follows : 
Take a piece of good tough wood, about 
one and a quarter inches by one inch, and 
six inches long ; bore a straight hole, halt 
an inch in diameter near one end and 
through the fiat side : fit it to one of the 
