Evening star. [volume] (Washington, D.C.) 1854-1972, 1940-09-04
Avoiding Boti|eneck
In Machine Tools Vital
ToDefense Production
Precise Measurements
Key TO Mass Production
Method for Weapons


This is the first of series OF
articles prepared by the National
Defense Advisory Commission to
oiue the public background on
the current program OF Building
for Defense"
What is the most important po-
tential bottleneck In the national
defense program?
It might well be any one of
number of problems that have con-
fronted the National Defense Ad-
visory Commission. For example,
the coordination of the resources of
American industry. Or the designing
of the particular equipment required.
Or the drawing of specifications for
contracts. Or provision Of adequate
facilities and materials to fulfill
contracts.
All these are important steps in
production. But the crucial factor,
the most potentially dangerous bot
tleneck, in the opinion of the Ma
tional Defense Advisory Commits
sion, is the preparation of machine
tools. Without machine tools there
could be no mass production OF au-
tomobileS, sewing machines, type
writers, airplanes, guns or tanks.
Trick in Measurement.
The technical definition of ma
chine tool is "a mechanically oper-
ated machine which removes metal
In the form of chips" Sounds
rather simple, but there's a trick
in it.
The trick is that a machine tool
manufacturer is man who meas
ures things down to two-millionths
of an inch.
When Eli Whitney built the first
cotton gin, he made an iron crank
to turn 1t and wooden handle to
fit the crank. When he built the
second, he made another iron crank
and another handle to fit that
crank. but the handle on machine
A wouldn't fit the crank on ma
chine B. Today. however, a motor
manufacturer can take any one of
million pistons and slip 1t into
any one of million cylinders, know
ing the fit will be perfect.
To make all this come out even,
It Is necessary to have standards
to 60 by. If pistons are to be made
that fit a million cylinders, they
can't be made about so big" That
is where the machine tool industry
ing devices. These are steel cubes
with square bases. They range
from 20 inches, absolutely even,
, down to two-hundredths of an inch,
plus or minus five one-millionths.
Casting Inaccurate.
The next step in the machine tool
industry Is production Of microm-
eter gauges which can be checked
for accuracy against these stand
ard blocks. The measurements can
be applied to finished work.
That is all preliminary to the
serious business of taking of those
little chips of metal. For instance,
no piece of metal can be cast &C
curately. If manufacturer starts
to make an airplane cylinder for a
thousand horsepower engine. he
casts a piece of metal. The foun-
dry men have shaped the mold but
as steel can't be cast accurately
with the holes, let us say, exactly
3 inches in diameter. so 1t Is cast
little smaller, about as inches.
1t is then put on a boring machine
where a drill spins around inside
the openings and cuts on the extra
metal, leaving holes that can be
finished to very accurate size.
Then, when the piston comes along
from another manufacturer, 1t has
been rnachined to the same accu-
racy and checked by a set Of the
blocks already mentioned, and 1t
fitsi
The business end of a machine
tool is always some sort of knife
or cutting edge. On a lathe, the
great ancestor of the machine tool
family. the work is mounted so
that it can spin around. As 1t
spins, the cutting tool is pressed
against it.
Cutter Must Be Steady.
To get that cutting edge to whit
de to the accuracy of a thousandth
of an inch, it is necessary to use
care in setting it. For that rea-
son, it may require ton or a 3-ton
machine to hold a few ounces OF
cutting tool. because If the tool IS
unsteady and gets a little out of
line, or is ever affected by heat, all
the fine accuracy OF the machine is
wasted.
But when these machines get cut
ting, they can turn out a sight OF
parts in short order. 1t may take
SIX months to build an automobile
gear cutter. But a good machine
tool can cut the main gear teeth Tor
the rear axle of tank In two min
utes. BY hand 1t would take
couple of days. That's why we get
production when the machines are
set
The production division OF the
commission reports that dennlte
progress has been made IN produc-
ing these machines and that no
actual delay exists in delivery thus
far. It takes several months for the
manufacturers to receive their con-
tracts. make ready their plant faclll-
ties to house these machines ana
locate skilled workrnen necessary 10
operate them. When all are ready,
the production can begin on a Dig
scale.
Coordination of Resources First.
Provision of machine tools, how
ever, comes far along in the pro-
cedureS that have concerned the Ma
tional Defense Advisory Commits
sion
First, it had to lay firm founda-
ton on which resources OF the
United States could be co-ordinateo
1t had to make every effort to speed
up current contracts for military
equipment.
Within eight weeks after forma-
ton Of the commission. Commission