The Manitowoc pilot. [volume] (Manitowoc, Wis.) 1859-1932, 1884-03-20
Huge Circular Saws That Do Not
Need Sharpening.

The largest circular saw that has
been sent out of this city recently, says
the New York Sun, was exactly six
feet in diameter. 1t was ordered by q
match company and went to Michigan.
tifty-two teeth projected from its rim.
1t is now revolving at the rate of 672
revolutions a minute, and is capable of
making ten-inch to twelye-inch cut
with each revolution. 1t can saw off
a forty-foot plank. therefore in an in
6nitesimal portion OF a minute, though
as matter of fact the frame on which
logs are fed to saw is adjusted to
move at about the speed at which
man can walk. At the rate, there is
nothing but whirr and a shrek to
announce the journey OF logs length.
This is not solid saw or it would have
more than one hundred teeth. y is one
of the new patterns, in which the teeth
are separate from the plate and can be
inserted and removed at pleasure. The
teeth in the sort of saw OF which this
monster is a specimen are little curved
bits of steel pointed like chisels at the
cutting end. They fit into round sock
cts cut cut of the edges of the saw
plates, and their little chisel blades
project slightly beyond the circle of the
plate.
SO4ld saws continue to be made in
great numbers. but the inventors of the
movable teeth, different patterns of
which are made by all saw manufac-
turers, are deriving fortunes, because
new teeth can be replaced for few
cents and in few minutes, and the
body of the saw remains the size it was
made, whereas solid saws have to be
newly filed and set and sharpened ev-
cry time they dull, process that con-
sumes time and requires the services
of a sawyer whose skill commands
good wages. Every cutting reduces
the size of the saw. A 72-inch saw is
big one. even in Michigan, where the
66-inch saw is in common use. There
these 53-ioot saws are run at a speed
OF tive TO seven hundred revolutions in
Norway pine logs, and they cut as
deep with each revolution as the mon
ster above described. The little chis-
el-bit teeth VIII chew out pine during
a whole working day, and an entire
set OF dull ones can be replaced next
day IN tive minutes for cents a tooth.
Some of the sawdust from one of these
great saws was sent from Michigan to
the establishment of q great sawmaker
tn this city. 1t was esteemed as a
curiosity. 1t was not dust at all, but
mass Of little pellets of wood, three
eighths of an inch in thickness. The
lumDermen prefer to waste lumber in
this way, provided they get speed out
Of their tools. These huge saws are
used singly in saving rough loo into
planks. Afterward the planks are re-
duced to desired widths bv edger saws.
which are smaller implements reyolv-
ing together at the proper distances
one from another.
A saw-maker must know whether or
not his customer wants to run his pur-
chase at a high rate of speed before
the saw is made. Saw-makers, in de-
veIoping disk of steel into a saw.
hammer it so as to leave either hard
or soft center. A saw that has soft
center will wabble in the middle if q
person takes hold of it by the edge and
shakes 1t. Ii 1t has hard center one
part will not shake more than anoth-
CT. A saw with q hard center, if driv-
Ell at high rate of speed, will not cut
straight. lis edge viii wabble. But
If 1t has soft center, and is sent
around at 4 rate of 700 to 500 revolu-
tions minute, the centrifugal force
Straining at the center stiffens the saw
and keeps the edge steady. To the
average mind it would seem that there
has been the same straining after or
namental effect in the vertical saws.
so odd are the shapes of the teeth. But
here, again, the study has been solely
to produce strength and cutting power.
Some OF the vertical saws have dull
teeth alternating with the sharp ones.
The dull ones do not reach out quite so
far as the cutters. Their purpose is to
clear the sawdust before the cutl-rs.