The Washington times., 1921-03-26
HOW METAL |SCUT
IN BUILDING CARS
Use Of Special Machines Has
Put American Auto Indus
try to Front.

You don't look for romance In an
automobile factory, but when you go
there you find it in the mystical
cainery. the fascinating recriprocs-
lion of ponderous cutting tools, and
the smooth, functioning of the drills.
says II. +. Blanchard. in Motor. Ex-
ccpt to the initiated every part is a
mystery but the first thought that
al ises in the mind of the layman is,
How do they cut metal? Cutting
wood is simple enough, but metal is
fard and tough and seems quite in
capable of cutting"
AS a matter of fact. cutting metal
8 not greatly different from cutting
wood. In either case the cutting
substance must be harder. wooden
knife will cut butter cheese. and
most foods because It Is harder than
any OF these things. A steel knife
VIII cut wood and will even cut
glass If IL be harder than the glass.
Extremely hard steel will cut almost
anything. and ii Is used almost eX-
Clusivcly for cutting metals. The
process differs however, in that
whereas a whiting, pairing action
viii cut wood, steel-cutter must
Eouge and rip off the surface OF the
Taetal. AS parallel in wood .
working. II we hold the knife blade
perpendicular, to the face OF the
wood. we scrape Without cutting IL.
So in working with metal, tha
blade. sometimes an eighth of an
inch thick and bearing small re-
semblance TO knife, is held per-
pendiculsr to the part and the metal
Is scraped.
a N NJ mr. a
Sometimes many cutting edges arc
formed into cutting wheel two.
three or more inches in diameter
The rotation of this wheel in a suit
able machine being used to smooth
off the surfaces of the part. Or the
part may be rotated or rcciprocated
while the cutting tool is held i'm
movable.
For example, let us take a piston
which is made of cast iron or alumni
mum. The casting is put in lathe
and rotated at a rapid rate while the
stationary cutting took is racked
slowly along it's surface to cut off the
excess metal and bring it down to
size. The grooves for the piston rings
are cut similarly. after which the
hole for the wristpin is bored, and
the piston is done. Special mach lines
have been devised to handle several
pistons at once, and they are so
cleverly made that their operation is
almost automatic. The genius and in
spiration entering into the compost
ton of such tools would, il applied
to art or literature. bring fame and
everlasting tribute to their origina-
torc.
The, machining OF cylinder block
is done in several stages. each of
which is intensely interesting to the
proverbial man in the street who by
chance has wandered into a motor
car factory Assuming that the cylin-
der block is of the detachable head
type, the. casting is smoothed off on
machine that has disc-like cutting
tool suggestive in its action OF ro-
tary floor polisher. The casting is
clamped to a sliding bed and fed
under this rotating tool whose hard
metal teeth take Off perhaps a six
teenth- inch 6f metal, leaving a smooth
surface behind. All four or six sylin-
ders are bored at the same time. When
this operation is complete the cast
ing requires the boring OF numerous
small holes for valve stems bolts, and
studs, but many of these are drilled al
one time, as for instance, all the holes
in the top of the casting. Such a ma
chine may have as many as twenty
five or fifty drills, each drill being of
just the right size and situated in
just the right place, so that when the
cylinder casting is put under the ma
chine and all these drills arc brought
down each holes is bored with scien-
tific accuracy.
DROr FORGlsGs.
The crankshaft and connecting rods
are drop forgings, drop forging Is
similar TO forging made by black.
smith, but the work is done by heavy
machine instead of by hand. A steel
Sic, each half having a recess in /.
that is just the shape of the part to
be forged, is placed in the machine.
one-hslf on r. large anvil, and the
other in the steam operated hammer
Then a piece OF white hot steel IS
laid on the lower half of the die. and
the metal is forged by repeated blows y
&C the heavy hammer. When hammer
cd to the shape of the die II is tenn
percd and passed on to a lathe whero
II is rotated and the stationary cut
ting tool liz used to smooth off the
surfaces which will At the bearings.
Finally, TO give extreme smoothness
and accuracy, these faces may be
sround.
Camshsfts and front axles arc
made in a similar manner. but rear
axles are usually pressed from steel,
as are frame members and tenders
Where bodies are built in quantity
some of the parts may also be OF
pressed steel, the forming OF fender.
fer example. being done in an cX-
tremely powerful press. Dies are
made to just the shape of the fender
the lower die being mounted on the