Heavy duty oil engines: their application and production (Paper

Library Digitised Collections
Title:
Heavy duty oil engines: their application and production (Paper)
Date:
1943
Persistent Link:
http://hdl.handle.net/11343/24900
File Description:
Heavy duty oil engines: their application and production (Paper)
130
VICTORIAN INSTITUTE OF ENGINEERS.
PAPER
HEAVY DUTY OIL ENGINES : THEIR APPLICATION
AND PRODUCTION.
By B. J. Peakman.
To those not intimately acquainted with heavy duty oil
engines, I will say at the beginning of my paper that I
have no intention of wearying them with figures, diagrams and
graphs of designs and performances, of the innumerable engines
on the market at the present day. Anyone so interested can
obtain all the technical data he requires by ready access to
modern books devoted to those aspects of heavy oil engines.
The history and the application of the heavy duty engine
must of necessity run together. To obtain a comprehensive
appreciation of the modern oil engine, a brief statement of the
stages of development is advisable. The Internal Combustion
Engine was built and used long before Watt constructed his
atmospheric steam engine, and it was not until the latter part
of the nineteenth century that the gas engine came into favour
commercially.
The first prime mover to displace the steam engine was an
explosion engine. Huggens is credited with the production of the
first internal combustion engine in 1680, gunpowder being the
explosive force, but the reassertion of atmospheric pressure after
the creation of a vacuum by the natural cooling of the gases
after explosion of the gun powder was the actual force. From
here we step up to the forerunner of our present-day war-time
adventure, the "gas producer" engine. This engine was built
by an Englishman named John Barber in 1791. Gas was distilled from coal, and mixed with air in a mixing chamber, and
ignited. The resultant gases impinged on the blades of a paddle,
this obviously being an attempt to operate the old-time water
wheel arrangement by gas in motion, instead of by flowing
water.
In mentioning gas producers I know that I immediately create
an interest among you, who are "petrol starved." The older
ones among us have been forced to become producer gas manufacturers and consumers ; the younger ones among us
eagerly sought it; but the older ones have memories
that charcoal was black and dusty, and has still to
be used in the same manner as it was thirty or
more years ago. We have fought shy of it as long as possible.
HEAVY DUTY OIL ENGINES.
1S1
Incidentally, I may mention that gas producer plants were made
in Victoria as long back as 1910, and some of them, we have
reason to believe, are still in use to-day, operating stationary
engines. The general arrangement and operation were then much
the same as it is now, but its component parts were built
extremely heavy.
It was left to Lenoir, in 1860, to make the first marketable oil
engine. This was double acting, and of the flat ported-valve type,
similar to steam - engine practice ; this type of valve persisted
for a considerable time in the Otto engine. A Frenchman named
Beau de Rochas, in 1862, proposed the four-cycle operation as
we know it up to this day. Though he never built an engine, he
laid down the fundamentals of efficiency so necessary to improvement, and it must be remembered that the Lenoir doubleacting engine was only 4% efficient, compared with the most
efficient engine of to-day giving about 42% efficiency.
Previous to the Otto cycle, an American, George Brayton,
patented an engine different from all others; his engine ran on
gas or oil introduced into a compression cylinder and ignited,
the resultant gases being led to the engine cylinder at constant
pressure, the piston being acted upon by this pressure throughout its entire length instead of (as now in our modern car
engine) the piston being set in motion by an almost instantaneous explosion. This engine made by George Brayton was very
efficient, but cumbersome and expensive to make, and so it gave
way to the Otto type, which was far more simple.
The heavy duty oil engine of to-day retains to a certain extent
the advantage of Brayton's constant pressure engine, in as much
as the heavy oil fuel is slow burning compared with petrol. The
advent of Dugald Clark's 2-stroke cycle engine, and of Charles
Ackroyd Stuart's Surface Ignition engine, is comparatively
modern history, for it was not until 1910 that the hot bulb or
surface ignition oil engine came into favour.
Dr. Diesel, the German engineer, in 1892 invented and. made
at Munchen his air-injection diesel' engine, which he tried to
run on coal dust. This engine promptly blew itself to pieces. Dr.
Diesel contrived to develop his engine with the aid of Krupps,
but disappointments met him, and he committed suicide by
drowning in the North Sea, on a voyage between England and
Germany.
The engine lost favour in Germany, but an English firm, the
"British
Diesel Company," continued ; and much of the credit
for the successful development, which usually goes to Germany,
was actually due to the persistent activities of British manufacturers. The oil engine has had more rapid and continuous
132
VICTORIAN INSTITUTE OF ENGINEERS.
development than any other type of prime mover, and, like the
Diesel engine, has had considerable variation of design and principles of operation, so that modern oil engines are now available
which are acceptable to all classes of users, and every requirement is now catered for. In Central Stations, the true Diesel or
air-injection engine has found favour for big power units; ships
of all kinds are equipped similarly. Latterly the airless injection
or solid injection engine has, in many instances, won very much
favour by large and small power users, and the operating costs
are well under the usual steam-plant records, and compare quite
favourably with the installation and running costs of the largest
central power stations.
Refrigeration plant engineers have readily adopted the oil
engine because the operating cost per ton of ice is considerably
lower than with the typical steam plant Mines and quarries,
water works, flour mills, railways, farm machinery, factories,
road rollers, motor lorries, cars and aeroplanes, all have claimed
the oil engine in their own particular sphere of usefulness. The
advantage of the Diesel engine for small horse-power is its
marked economy over a steam plant, and over engines using
refined fuel. The gain is due to the fact that as steam equipment
becomes smaller, its fuel consumption per horse-power increases.
A Diesel engine, whether large or small, has approximately the
same fuel consumption. This advantage makes the Diesel engine
in smaller units very attractive. Several small units in one plant
are preferable to one of much larger power ; each engine can be
run at its most economical load, and the cost of buying and
maintaining a spare unit is kept down.
Most engineers, and very many laymen, have seen the modern
compression ignition oil engine using the Bosch type pump and
atomiser, and most of you know something about it. Comparatively few have any knowledge of a Compression Ignition
engine which does not have in its make-up a pump of some
description to supply its motive power—an engine we may call
a pumpless injection engine. I refer to the Brons type of Ignition engine, known in America as the livid engine, because this
was the name of a man who held the manufacturing licence in
1917 in America. I will later explain this ignition principle in
detail.. Very shortly after America took up the manufacture of
this type of heavy oil engine, a well-known Melbourne engine
firm, then making petrol-kero-spark-ignition and producer gas
engines, decided to adopt the Brons type of ignition, and within
a"very short time met the same sort of trouble as did Dr. Diesel.
The engine blew itself to pieces. Some of the interested experimenters had near-misses.
HEAVY DUTY OIL ENGINES.
133
Nothing daunted, we .proceeded to cast a new crankcase, and
tie the whole contraption together with 14 in. studs through a
22 in. dia. bosses cast the full depth of the crankcase, and to
stiffen up sundry other parts which gave us fears of parting,
and so finishing the job it tried to do previously. This engine
weathered all the storms we could shower upon it, and from
then on we went ahead, and after experimenting and testing for
about two years what is believed to be the first Diesel-type
engine made in Australia was put on the Australian market by
way of the Melbourne Royal Agricultural Show about 1919.
For the most part, the engine is a typical 4-stroke cycle heavy
duty oil engine, but the ignition is entirely different, n.) blow
lamp, no spark plug, no hot bulb, no magneto, no fuel pump, yet
it started from cold by revolving the crank by hand.
In the Brons engine the cycle is, in principle, the same as the
Diesel cycle, and therefore the Brons engine has the same high
efficiency as the Diesel engine. The simple and safe spraying
device gives very important advantages to the Brons engine,
working without an air compressor for high pressure, and without a fuel pump. By these advantages it is possible to build at
reasonable cost even small oil engines, with low fuel consumption, and very easy to attend to.
A mixture of fuel and air is introduced into an ignition
chamber during the inlet stroke. This ignition chamber, in the
form of a steel cup, is located directly underneath the cylinder
head, and communicates with the combustion chamber proper
through a number of small orifices in the wall of the cup near
the bottom thereof. Toward the end of the compression stroke,
air is forced into the ignition chamber through the small orifices, and the heat of this air ignites the mixture of air and fuel
therein. In normal operation the wall of the ignition chamber
is at a high temperature, and since the fuel remains in the
chamber for a period corresponding to more than the time of a
piston stroke, the greater part of the fuel probably is vaporised.
The mixture within the ignition chamber is over-rich, and only a
portion of the fuel can burn in the chamber, but this partial
combustion of the ignition chamber contents results in a rise
in pressure, which causes a large portion of the contents, including most of the still unburned fuel, to be ejected from the
chamber through the small orifices, and combustion to continue
in the regular combustion chamber. The operatior of the cup is
based on the fact that every oil, no matter how heavy it may be,
contains some light hydrocarbons that will vaporise or distil at a
fairly low temperature. The explosion of these lighter parts of
the fuel provides the means whereby the remainder of the fuel
is injected into the engine cylinder in a finely atomised condi-
134
VICTORIAN INSTITUTE OF ENGINEERS.
tion. A further matter of common knowledge is that the temperature of ignition of an oil is dependent upon the degree of
atomisation.
Air only is drawn into the cylinder, The air intake valve is
held open until near the end of the suction stroke, as is also the
fuel valve. The amount of oil drawn into the fuel cup does not
depend upon the length of time that the valve is open, but on
the amount passed by the needle valve connected to the governor.
Fig. 1.—Brons Engine Ignition Device.
The foregoing was the inventor's theory of the operation of
the engine, but diagrams taken with an engine indicator, set 90°
out of phase with the crankshaft, show that under full load at
least ignition began in the main combustion chamber earlier
than in the ignition chamber. This is not at all surprising, because during the suction stroke there is a tendency to draw fuel
through the orifices during that stroke. During the compression
stroke, owing to the strangling effect of the orifices, the pressure
is always higher in the cylinder than in the ignition chamber,
and the temperature therefore also is higher in the cylinder,
which would naturally lead to an earlier ignition in the cylinder,
provided sufficient fuel is present there. However, the mixture
in the cylinder is exceedingly lean, while that in the chamber is
over-rich, with the result that after ignition is initiated the
pressure rises more rapidly in the ignition chamber than in the
cylinder.
HEAVY DUTY OIL ENGINES.
135
The ignition cup and associated parts are the distinctive features of the Brons engine. This engine was developed to a certain
degree by Deutz. Motor Works, in Germany, during the first
decade of the present century, but was later abandoned by that
concern. It was built also by firms in England, Holland, and
Belgium. The unit shown (Fig. 1) is built in the form of a plug
set into a bore in the detachable cylinder head. The ignition cup
at the bottom of the plug is closed on top by a small valve, which
in the earliest designs opened automatically under the effect of
suction, but in later designs was opened positively by a cam
mechanism. Fuel entered the space around the valve stem
through a pipe connection on one side, while air entered through
a small drill hole on the opposite side.
The arms of the valves were connected by a link, which in
turn was connected through another link to the governor. Thus,
while the Brons was very sensitive to changes in load, and was
consequently used mainly for marine service, the Hvid was capable of a certain speed control, and more suitable for land
service.
A 54 by 9 in. single-cylinder engine of the Hvid type was
tested by Prof. Daniel Roesch, of the Armour Institute, Chicago.
Employing a compression pressure of 390 lbs. per sq. in. it developed a maximum pressure of 670 lbs. per sq. in., and an
i.m.e.p. of 87.3 lbs. per sq. in. In a later design the inventor,
R. M. Hvid, is said to have used a small quantity of compressed
air to inject fuel into the ignition cup during the inlet stroke.
This permitted of operating the engine on the two-stroke cycle,
using kerosene for fuel. It is understood that the main difficulty which led to their abandonment was inability to prevent
gumming up of the fine orifices in the ignition cup.
The Brons-Hvid type engine manufactured to-day in this
country does not suffer in the least degree from gumming of
atomiser holes, nor from the formation of carbon in or about
the atomiser. This type of engine will operate successfully on
any oil which will flow. An enterprising dairy farmer was unfortunate enough to run out of crude oil and kerosene, so the
bright idea struck him that cream spilt on the fire a few evenings previously had blazed itself out, and so, armed with a cream
can, he went !to his engine shed, charged the fuel tank with
cream, and finished his milking
Many thousands of this type of engine have been made in
sizes from 2 h.p. to 20 h.p., and at the present time Government
Departments are being supplied with a large number of 3-ton
road rollers, fitted with a 6 h.p. Brons engine of a type embodying many desirable features, such as entirely enclosed dry sump
136
VICTORIAN INSTITUTE OF ENGINEERS.
crankcase, the cylinder, the big-end, and main bearings all being
independently pressure lubricated by an all-Australian made
and designed mechanical oiler of novel design. The main bearings of the engine are white metal lined gun-metal cases, and
are easily adjustable for wear, making it independent of imported roller or ball bearings so difficult to obtain at the present time. The engine was designed for the roller to undertake
the arduous work of road and drome making in the deserts of
Syria and the East, and for Australia, so a very efficient aircleaner is, of course, standard equipment. I may mention here
incidentally, that Masonite, instead of the usual 1 in. pitch corrugated iron, is used for the roof, making for more comfort in
the intense heat of the tropics.
This type of engine is made in two other sizes, and is particularly suitable for farmers and farm conditions for operating
milking machines, pumps and electric generators, also for light
railway engines and marine engines, and so on. Incidentally, I
have known them used for the very base purpose of killing rabbits by putting the exhaust into a rabbit burrow, but though the
average exhaust of a Diesel engine is not so clean as that of a
petrol engine, it is not nearly so deadly.
The hot bulb engine is an exceptionally rugged prime mover,
particularly suitable for driving saw-mills, pumps, tractors and
mining machinery, and are made in Australia up to 50 h.p. in
single cylinder sizes, making for simplicity of operation and
attention, small number of replacements, and low running costs.
This type of engine is started by heating the tip of the bulb by
a blow lamp or the like, the fuel being gravity fed to a high
Hot Bulb Ignition Engine (35-40 H.P.}.
HEAVY DUTY OIL ENGINES.
137
pressure plunger pump, given a variable stroke by the governor,
the fuel being pumped to a spraying device directly over the hot
bulb where, under compression, it is ignited, and the usual cycle
operates. This is a two-stroke cycle low compression engine, in
the regions of 100 lbs. compression pressure,
~
~.~.......~~~\\\\\\\\\\\\1\\w~: • :•v~.d~~~\\~~~•~~~id
%n..,,.
Fig. 2.
The hot spot or hot tube engine (Fig. 2) is more dependent
on a higher compression pressure for its ignition. It is started in
a similar manner to the hot bulb engine, but the area of heated
surface is considerably less. The high pressure pump is gravity
fed, and directs its charge of fuel, in a governed quantity, to a
spraying device, situated at an angle to the hot tube, and only
part of the fringe of the atomised fuel enters the tube. The compression pressure, about 240 lbs. per sq. inch, causes ignitiol,
and the usual cycle of operations continue.
Single cylinder engines of these types, operating on the twostroke cycle, constitute one of the simplest forms of modern
engines, and are therefore highly suitable for farm work, and
for power units of road rollers, saw-mills, water pumps, power
stations, an,d the like, in the hands of semi-skilled attendants.
138
VICTORIAN INSTITUTE OF ENGINEERS.
PRODUCTION.
The production of engines of any type calls for extreme care
and research in design and manufacture, and the heavy duty oil
engine is no exception. In a wet sump engine even the shape of
the crankcase and the parts operating therein can have, amongst
other things, a big effect on oil consumption; lubricating oil
pipe-leads, carelessly or indiscriminately placed, can also have
a detrimental effect. This applies to four-stroke cycle engines,
whilst the shape and volume of the crankcase of two-stroke cycle
Fig. 3.
engines are also of vital importance. These points are sometimes
overlooked by some designers, and I mention them to stress the
necessity for careful attention to detail in designing a satisfactory product.
The largest component of heavy duty oil engines is the body
or crankcase, which sometimes includes the cylinder and/or the
water jacket to receive the liner. These castings are inspected
before being stored for seasoning. They must be free from porosity and have a smooth skin A little extra care in moulding more
than offsets the cost of fetling and filling before painting. When
they are required for the machine shop they are tested, and if
O.I. the first operation is proceeded with. The suitability and
quality of materials generally must be determined for every
component.
Rigid testing of material and detail inspection are essential
during manufacture. No component is "good enough" if it is
HEAVY DUTY OIL ENGINES.
139
not up to specification in every way. This means that all parts
must therefore be interchangeable, and to obtain the necessary
accuracy, jigs, gauges, and special tools must be designed and
used for every operation.
Whenever possible, tool setting pads are provided on jigs; and
always liberal use of gauges is resorted to to ensure accuracy and
its resultant interchangeability. Crankshafts made of forged
alloy steel are heat treated and then machined on special crankturning lathes, and are finished by grinding to fine limits set on
"go" and "not go" limit gauges. The first component at every
operation is inspected and must be passed by a viewer before
batch is proceeded with. This rule holds good for all components.
Cylinder heads with intricate cores need special care in moulding, and in the selection of material used. Castings must be perfect in shape and solid in mass. Careful inspection and high
pressure air and water testing are resorted to to minimise waste
time in machining undesirable castings. All heads are machined
to gauges and drilled in jigs; then again tested before final inspection. Connecting rods and all the smaller parts are jig produced and subjected to the same system of inspection. The production of atomisers for the Brons-Hvid type of engine, which
engine was described in the first part of my paper, entails
material quality and machining accuracy to the same degree as
any other atomiser used in oil engines. Once again the use of
jigs and gauges and special tools makes it a comparatively easy
component to produce, and once again a sound casting is
essential.
The needle valve body of special steel, and the fuel cup of
special steel, are machined so that very slight grinding-in is
required to make a metal to metal high-pressure, gas-tight joint
on the pressure face, a copper joint being sufficient for the top
or non-pressure face.
The fuel cup must be very accurately and smoothly machined,
especially inside, to ensure correct capacity and the uninterrupted flow of fuel and combusted gases; turning is done on
capstan lathes to precision gauges. The milling of the flat is also
an accurate operation to maintain a given length of jet hole,
which is jig-drilled on a high speed drilling machine running at
about 16,000 r.p.m. All the component parts of the governor are
produced with the due accuracy required, as are also the lubricating oil pump, flywheels, and all other parts. After inspection
they are received by the component store, and are issued from
there in planned batches to component assembly benches. Once
again the inspection plays its part before assembled components
140
VICTORIAN INSTITUTE OF ENGINEERS.
are returned to the component store to be issued to the engine
fitting benches, from which the engines arrive at the test beds,
where testing is proceeded with. Adjustments are made, as found
necessary, and after a running-in period a test brake is applied
until the performance satisfies a given specification. The piston
is withdrawn and inspected, then replaced, and a final run and
adjustment on a maximum brake horse-power load must satisfy
the keen inspection of the chief tester.
In the paint shop the engines are fitted with metal and rubber
hoods, also grease is applied over the working external parts to
prevent the paint spray adhering thereto, and so interfering
with the satisfactory functioning of the engine. The average
purchaser of an engine likes a bit of colour so, after the final
coat is dry, a lining machine lays red and yellow lines on the
green base; the engine works just as well without this waste of
good material and time, but the purchaser, especially the farmer,
likes it, so he must have it.
The Brons-Hvid system of engine is made in wet sump and
dry sump types, but in the case of the dry sump a mechanical
oiler is used to force-feed oil to working parts, whereas in the
wet sump a circulating gear-pump is used. The mechanical forcefeed oiler with visible flow is made with the same precision as
the engine. The war caused the substitution, for the Americanmade oiler used for many years, of an oiler made on the premises. A brief description of the oiler may be of interest, as it
embodies the use of two well-known systems in a new way. The
cast-iron body contains a rotary gear pump and a number of
plunger pumps. This rotary gear pump is the primary which
forces oil to a gallery reservoir at constant pressure. From this
gallery the oil is bled off through adjustable needle valves to
drip through sight glasses; the drops of oil fall into bell-topped
tubes ; at this stage the independent plunger displacement
pumps force the measured oil, through each pipe lead, to the
working part selected, such as the cylinder, the main bearings,
big-end bearing and so on. The oiler has been fitted to a large
number of 3-ton road rollers, originally made for the British
Government, as mentioned earlier. These are being used for
road-making and rolling, aero runways, and, by the cement penetration method, for the making of storage floors, and the like.
Larger rollers are fitted with 2-stroke cycle engines of the hot
spot type, made in 10-15 h.p. and 20 h.p. These engines are similar to those used for stationary work. Two-stroke cycle engines of
the hot bowl, low compression type are produced in 25 h.p., 35
h.p., and 50 h.p., and, as with the production of small 4-stroke
cycle engines, jigs, gauges and special tools are used extensively,
HEAVY DUTY OIL ENGINES.
141
shop inspection is resorted to for all large components, whilst
the smaller components follow the same route as those of the
smallest engines. Liners, all of which are of the wet type,
are bored on a duplex boring machine, turned on mandrel
centres, and ground in a home-made cylinder grinder of unique
design. Two-thousandths of an inch is the allowed total error in
grinding, that is, out of round, out of straight, and out of parallel for diameters over 5i in. Under this size, one-thousandth is
the required limit. All liners are air tested under water. All
crankshafts up to 10 h.p. are of ground finish, whilst on larger
sizes big-end bearing surfaces are lapped. Roller bearings are
used for main bearings ; ` ` go" and "no go" ring gauges being
used for the bore of cases, and for the inner ring position on the
crankshafts. These ensure keeping sizes within the limits of the
roller bearing manufacturers' specifications. Fuel pumps for all
these 2-stroke cycle engines are made of hard phosphor-bronze,
-with hardened steel plungers, ground and lapped to extreme
accuracy, and the pump barrel is honed. A leather gland is
fitted, but this serves to keep out dirt rather than prevent leaks.
The fit of the plunger is such that a gland to prevent leakage is
not necessary. The governor assembly of the larger engines is
composed- of two eccentrics operated by flyweights, the speed of
the engine varying the amount of eccentricity, alters the length
,of travel of a tappet operating on the plunger of the pump, thus
controlling the amount of fuel forced through the atomiser. All
parts of -the governor are interchangeable, being completely
machined in jigs. Limits of accuracy are fixed according to requirement. No time is wasted on unnecessary finish and unnecessary accuracy. Cylinder heads are all of the water-jacketed type,
and after machining are subjected to the usual inspection and
are water tested. Pistons after heat treatment are turned, bored
and ground to give the requisite clearance in the liner, the correct type of iron having been used to avoid ageing and temperature growth, and to resist wear. The gluts of pistons are
machined on the ring pressure face to a perfectly flat plane. It is
useless to fit well-made flat-face rings into gluts which are not
equally flat. The periphery of piston rings will quickly make a
bearing for themselves, but the sides must be gas-tight right
from the start.. Time will not permit going into technical details
of ring design aind manufacture, but I will say that gluts and
rings, accurate enough for petrol engines, are not necessarily
accurate enough for Diesel engines; therefore a high degree of
accuracy must be maintained in these components. The rings of
two-stroke cycle engines are pegged to locate the split of the
rings in staggered positions (Fig. 4) ; the ends of the rings
should be of Y formation, not the usual combination of semi-
142
VICTORIAN INSTITUTE OF ENGINEERS.
•
Fig. 4.
r"-
.~í~~
i~í~í~i~N~i~i~i~/~í~i~í~í~~
~
.~i~i~i~
.
í
~ ~. N~. ~~í~
S~Âf~í~í~. ~. ~í~Â'
. ~~. ~..~ÂI~.
SMALL, END BUSH
Fig. 5.
HEAVY DUTY OIL ENGINES.
143
circle and square formation. This design ensures freedom from
loose peg trouble, so often met with. I think this procedure is
superior to that of the German Junkers engine firm, who fit
brass pegs, the only apparent reason for this being to prevent
damage should a peg come adrift. Since fitting pegs and rings
as described no trouble whatever has occurred.
The lubrication of the small-end bearing of two-stroke cycle
engines has demanded and received much experiment and research. A very unconventional type of bearing, which has stood
up to hard work in hundreds of engines built in the last four
years, can be best described by stating that the gudgeon pin
transfers its pressure not to the phosphor-bronze bearing, but
.rather to the surface of a lake of oil, four-thousandths of an inch
in thickness, retained within four walls (Fig. 5). This b-aring
has proved itself, and has confounded all its critics.
Before fitting this type of bearing, an overload of 14% on a
35 h.p. two-stroke cycle engine, could be maintained for twenty
minutes. At the end of this time the bearing was quite dried out
,and the gudgeon pin had become heated that it had become quite
blue from excessive heat. With the use of this new bearing, the
same overload (that is 14%) can be carried for any length of
time without showing any tendency to dryness or excessive heat.
The big-end bearing is lubricated through the crankshaft, to
which is attached a banjo carrying the oil feed into it by a forcef eed oiler through a drilled hole in the crankshaft leading to the
big-end bearing.
The bolts holding that bearing are locked by means of flat
sheet-steel washers, one square edge of which lies along a straight
machined shoulder, and one corner of the washer is finally
turned up flat against one flat of the nut. We find this method
far preferable to the split pin, which is always likely to wear
through, and fall adrift if the slightest looseness develops. No
originality is claimed for this flat lock-washer. It was adopted
from a Citroen car of 1926, and has been used wherever possible
since that date, and is undoubtedly the safest method, except
perhaps the very drastic one adopted by the Wolseley Tool and
Gauge Co. on an early racing car made by them about the year
1904; after one race it was found that quite a number of bolts
had become loose, so, to make sure this did not happen again,
every nut had its bolt rivetted over it. I don 't think the man
who had the job of stripping that car down after the next race
ever finished the job. I happened to know him. Andree Citroen
must have struck similar trouble, which caused him to adopt the
flat steel lock-washer.
144
VICTORIAN INSTITUTE OF ENGINEERS.
These washers, by the way, are a simple press job. It is surprising to see the number of ways press work can be introduced
Into the building of an engine. Generally it is much cheaper
than any other method, and if the finished product does not
suffer in any way from the introduction of pressed components,
then it is justified on the score of economy; not only that, pressed
components are usually lighter, stronger, and often more suitable than machined parts, which also cost more to produce.
The long experience of many mechanical engineers in Australia and abroad has made possible the armament production
brought to the successful issue, of which we hear so much. To
say that I, personally, am satisfied with the results would be
stating an untruth. I am of the opinion that what has been done
is not the wonderful achievement the newspapers would have us
believe. We all agree that a large amount of good work has been
accomplished, but a lot more could have been done, and at less
cost, if all the sources of knowledge and experience had been
tapped in the initial stages of armament development and production. If the necessary capital is available, then the same
technique, the same practice and experience necessary to produce heavy oil engines successfully are all the requirements
necessary to produce guns and shells, and all the armaments of
modern warfare.
On the screen were sh own cinema views of the finished
machines in operation in many parts of Australia, also of their
production; and the .production of some of the important parts
of a gun.
In conclusion, the author and Mr. E. J. McDoNALD expressed
their thanks to Mr. C. D. TIIOMPSON and the staff of the Melbourne Technical College for their valuable help and courteous
co-operation in the reproduction of diagrams and other illustrations.