THE YOUNG SCIENTIST. 
171 
Something About Saws— V. 
BY "our NED." 
OMETIMES the amateur may 
have occasion to use and care 
for saws that are not intended 
for cutting wood; and when 
such is the case, he will find it to his ad- 
vantage to possess some knowledge of the 
manner in which such saws are filed and 
used, and such other useful information 
about them that may be requisite. Doubt- 
less every boy who reads the Young Sci- 
entist has noticed a tool hung up in his 
father's kitchen shaped something like 
the illustration shown at Fig. 1 ; and al- 
Fig. i. 
though he may have seen it often, unless 
he saw it used by the cook, he would 
probably never suspect its real mission. 
This is a butcher's saw, and its chief use is 
to sever bones, but unfortunately for the 
saw, when it gets into the kitchen it is 
made to do service for a half-dozen tools. 
It is frequently used by the " hired help " 
for cutting kindling-wood, and it often 
finds itself struggling " tooth and nail " 
with some tack or tenpenny nail that re- 
fuses to move from the path it is forced to 
follow, and there are instances where it 
has been known to do service as a 
hatchet. 
The form of teeth for tins kind of a sa w 
are shown at Fig. 2; they are equilateral, 
The surgeon's saw— which may also be 
said to partake somewhat of a butcher's 
saw— is treated a little differently from 
the legitimate butcher's saw, though botli 
of them are intended for cutting bones^ 
This is owing to the fact that the human, 
bone in a live person is not nearly so hard 
and brittle as the bones usually operated 
on by the ordinary butcher's saw. 
Being softer and somewhat porous, the 
living human bone requires a saw with a 
little more pitch, and a more acute bevel 
than is necessary for a butcher's saw, and 
it should be filed and jointed with the 
greatest care, every tooth being on a line, 
and jointed so that every tooth 
will be in a lino on their side- 
cut-ting edges. 
Fig. 3 shows the form of 
teeth adapted for these saws. 
It will be noticed that the 
form of teeth shown is some- 
thing similar to teeth prepared 
for cutting hard wood. The 
number of teeth to the inch required 
for these maybe from fourteen to twenty, 
according to the work required to be 
done. 
Fig. 3. 
The next saw under notice will be the 
" hack-saw," or the blacksmith's saw, as 
it is sometimes called. This is used for 
cutting iron or brass. The blade should 
be hard, and the line of teeth perfectly 
straight. 
! Fig. 4 shows one of the better sort of 
Fig. 2. 
which gives the pitch of the teeth an 
angle ' of forty-five degrees, front and 
back. To work nicely these saws should 
be well and truly jointed, filed square on 
front and back, and should liave from 
twelve to eighteen teeth to the inch. Very 
little set is required in these saws. 
Fig. 4. 
these saw^s. Like the butcher's saw and 
buck-saw, it comes in for a good deal of 
hard usage, but its character and vitality 
is such as to render it invincible, and 
though in many cases it w^ould work bet- 
ter if cared for properly, it manages to 
perform its duties with a fair degree of 
satisfr.ction. 
