Green-Mountain freeman. [volume] (Montpelier, Vt.) 1844-1884, 1852-04-08
The Tunelling Machine.

AS unSI1AuSo AAAS0AAO'
A report in Pittsfield paper that the tunel-
ing machine was in Berkshire county, on it's
wuv to its lob in the Hoosc mountain, made US
regret that we had been too late to see the won
der before it left our city, but on particular in
qury we found that we had plenty of time. The |
machine has not left the city, but it is at Mr..
Souther's works in South Boston, not yet finished.
We had the pleasure yesterday of looking at its
gigantic casting, and of inspecting model by
which its mode of operation can be readily un-
derstood.
1t is the application to the task of boring "a
foot hole through the mountain Of plan Of stone
cutting by machinery, which is now in use
at the Quincy granite quarries. The application
svery ingenious, but how we'll it will work re-
mains to be seen. Perhaps by brief descrip-
ton we can enable our readers themselves to
guess at the probability
The cutting tool to be employed is not a CHS
el, but small wheel the periphery of which is
brought to an edge. A series of these wheels
being carried back and forth over the face of
block of granite, are found to work it rapidly
Now suppose hoop "a feet in diameter 10 be
armed on one edge with those cutting wheels or
rollers, and to be turned on its axis with the
armed edge pressed against the face af the rock,
and we shall see that it will cut groove or chan
mel of its own dimensions. Such channel or
heading the machine is to carry in three feet,
and also drill hole in the center. 1t will then,
being mounted on trains, be moved back and
charge ofpowder or gun.cotton will be eXplo-
ded in the central hole which will tear out the
rock.
The mechanism by which the cutting of the
channel and the drilling Of the central holes are
to be effected, at the same time, seems well
adapted to the purpose. The immense hoop is
mounted on a strong wheel like tire, projecting
forward in front, 8 feet beyond the felloes'
There are on its periphery II Of the small cutting
wheels, placed at different angles, so as to cut
the grove larger than the hoop itself, and let 1t
work freely. These cutters are disposed IN four
groups of 2 or 3 each and behind each group Is
a scraper which collects the chips, and carrying
them off on an inclined plane, loads them at IN
tefvas into cart which stands underneath on
one side.
This great wneeT u aagSs4oit, is mounted on
large hollow shaft or arbor, from the center of
which drill worksto make the central hole.
Motion is given to the great wheel not through
its arbor, but by shaft, parallel with that arbor
and above it, bearing pinion, which tooths into
: the inside of the great hoop.
And fixed ring, toothed on its inside, gives
motion to the drill in the center the main shaft
The same shaft which drives the great Wheel
! also drives a feeding screw, which carries the
main shaft and wheel forward on ways, one-eight
an inch for each revolution of the cutting hoop
, The whole of this gigantic machinery is borne
upon mammoth railway carriage offour wheels,
: which, when the machine is boring, is to be
! braced firmly against the walls of the tunnel.
The driving power may be either a stationary
f steam engine at the mouth of the tunnel connec-
, ted by bands or it may be a locomotive, noun
ted on trains.
AS the boring machine is already set up on its
| broad gauge wheels, it begins to develope its
mighty proportions. 1t looks as if it might walk
: through mountuin. When finished it will
weigh 80 tons, every ounce of 1t is iron, steel
r and brass unless it be the habbtng of soft met
r al which lubncates its enormous joints. To
move it to the scene of its operations it will be
4 taken to pieces. The heaviest piece will weigh
:, only 8 tons.
$ AS the cutting quality of the invention has
r been tested satisfactorily on granite, there is no
reason to believe that it will fail on softer rock
h and as to the adequacy of the proposed machin,
cry to turn the cutting quality to good account in
y the tunnel, we think there cannot be two opin-
o ions among practical mechanics who nspects the
= model. 1t has every appearance of having the
J. living gn-uhead principle in it. To say nothing
4, of the Hoosc tunnel which it is expected to re.
d duce to feasibility, it can hardly fail to work
revolution in regard to deep cutting on railroad;
d generally.
e If this machine should, work as well as, ex
2. periments on Quincy granite have given reason
to hope it will, two such, working at both ends
of will finish the Hoosic tunnel IN two years, ant
IS keep most Of the Sabbaths, as required.
i'd mOntOealth.