QUESTIONS ASKED ENGINEERS WHEN APPLYING FOR A LICENSE.[7]
Footnote 7: Furnished by courtesy of a friend of Aultman & Taylor Co.
Q. If you were called on to take charge of a plant, what would be your
first duty?
A. To ascertain the exact condition of the boiler and all its
attachments (safety valve, steam gauge, pump, injector), and engine.
Q. How often would you blow off and clean your boilers if you had
ordinary water to use?
A. Once a month.
Q. What steam pressure will be allowed on a boiler 50 inches diameter
⅜ inch thick, 60,000 T. S. 1-6 of tensile strength factor of safety?
A. One-sixth of tensile strength of plate multiplied by thickness
of plate, divided by one-half of the diameter of boiler, gives safe
working pressure.
Q. How much heating surface is allowed per horse power by builders of
boilers?
A. Twelve to fifteen feet for tubular and flue boilers.
Q. How do you estimate the strength of a boiler?
A. By its diameter and thickness of metal.
Q. Which is the better, single or double riveting?
A. Double riveting is from sixteen to twenty per cent stronger than
single.
Q. How much grate surface do boiler makers allow per horse power?
A. About two-thirds of a square foot.
Q. Of what use is a mud drum on a boiler, if any?
A. For collecting all the sediment of the boiler.
Q. How often should it be blown out?
A. Three or four times a day.
Q. Of what use is a steam dome on a boiler?
A. For storage of dry steam.
Q. What is the object of a safety valve on a boiler?
A. To relieve pressure.
Q. What is your duty with reference to it?
A. To raise it twice a day and see that it is in good order.
Q. What is the use of check valve on a boiler?
A. To prevent water from returning back into pump or injector which
feeds the boiler.
Q. Do you think a man-hole in the shell on top of a boiler weakens it
any?
A. Yes, to a certain extent.
Q. What effect has cold water on hot boiler plates?
A. It will fracture them.
Q. Where should the gauge cock be located?
A. The lowest gauge cock ought to be placed about an inch and a half
above the top row of flues.
Q. How would you have your blow-off located?
A. In the bottom of mud-drum or boiler.
Q. How would you have your check valve arranged?
A. With a stop cock between check and boiler.
Q. How many valves are there in a common plunger force pump?
A. Two or more--a receiving and a discharge valve.
Q. How are they located?
A. One on the suction side, the other on the discharge.
Q. How do you find the proper size of safety valves for boilers?
A. Three square feet of grate surface is allowed for one inch area of
spring loaded valves; or two square feet of grate surface to one inch
area of common lever valves.
Q. Give the reasons why pumps do not work sometimes?
A. Leak in suction, leak around the plunger, leaky check valve, or
valves out of order, or lift too long.
Q. How often ought boilers to be thoroughly examined and tested?
A. Twice a year.
Q. How would you test them?
A. With hammer and with hydrostatic test, using warm water.
Q. Describe the single acting plunger pump; how it gets and discharges
its water?
A. The plunger displaces the air in the water pipe, causing a vacuum
which is filled by the atmosphere forcing the water therein; the
receiving valve closes and the plunger forces the water out through the
discharge valve.
Q. What is the most economical boiler-feeder?
A. The (Trix) Exhaust Injector.[8]
Footnote 8: So says one expert. Others may think otherwise.
Q. What economy is there in the Exhaust Injector?
A. From 15 to 25 per cent saving in fuel.
Q. Where is the best place to enter the boiler with the feed water?
A. Below the water level, but so that the cold water can not strike hot
plates. If injector is used this is not so material as feed water is
always hot.
Q. What are the principal causes of priming in boilers?
A. To high water, not steam room enough, misconstruction, engine too
large for boiler.
Q. How do you keep boilers clean or remove scale therefrom?
A. The best “scale solvent” and “feed water purifier” is an honest,
intelligent engineer who will regularly open up his boilers and clean
them thoroughly, soaking boilers in rain water now and then.
Q. If you found a thin plate, what would you do?
A. Put a patch on it.
Q. Would you put it on the inside or outside?
A. Inside.
Q. Why so?
A. Because the action that has weakened the plate will then set on the
patch, and when this is worn it can be repeated.
Q. If you found several thin places, what would you do?
A. Patch each and reduce the pressure.
Q. If you found a blistered plate?
A. Put a patch on the fire side.
Q. If you found a plate on the bottom buckled?
A. Put a stay through the center of buckle.
Q. If you found several of the plates buckled?
A. Stay each and reduce the pressure.
Q. What is to be done with a cracked plate?
A. Drill a hole at each end of crack, caulk the crack and put a patch
over it.
Q. How do you change the water in the boiler when the steam is up?
A. By putting on more feed and opening the surface blow cock.
Q. If the safety valve was stuck how would you relieve the pressure on
the boiler if the steam was up and could not make its escape?
A. Work the steam off with engine after covering fires heavy with coal
or ashes, and when the boiler is sufficiently cool put safety valve in
working order.
Q. If water in boiler is suffered to get too low, what may be the
result?
A. Burn top of combustion chamber and tubes, perhaps cause an explosion.
Q. If water is allowed to get too high, what result?
A. Cause priming, perhaps cause breaking of cylinder covers or heads.
Q. What are the principal causes of foaming in boilers?
A. Dirty and impure water.
Q. How can foaming be stopped?
A. Close throttle and keep closed long enough to show true level of
water. If that level is sufficiently high, feeding and blowing off will
usually suffice to correct the evil.
Q. What would you do if you should find your water gone from sight very
suddenly?
A. Draw the fires and cool off as quickly as possible. Never open or
close any outlets of steam when your water is out of sight.
Q. What precautions should you take to blow down a part of the water in
your boiler while running with a good fire?
A. Never leave the blow-off valve, and watch the water level.
Q. How much water would you blow off at once while running?
A. Never blow off more than one gauge of water at a time while running.
Q. What general views have you in regard to boiler explosions--what is
the greatest cause?
A. Ignorance and neglect are the greatest causes of boiler explosions.
Q. What precaution should the engineer take when necessary to stop with
heavy fires?
A. Close dampers, put on injector or pump and if a bleeder is attached,
use it.
Q. Where is the proper water level in boilers?
A. A safe water level is about two and a half inches over top row of
flues.
Q. What is an engineer’s first duty on entering the boiler room?
A. To ascertain the true water level.
Q. When should a boiler be blown out?
A. After it is cooled off, never while hot.
Q. When laying up a boiler what should be done?
A. Clean thoroughly inside and out; remove all oxidation and paint
places with red lead; examine all stays and braces to see if any are
loose or badly worn.
Q. What is the last thing to do at night before leaving plant?
A. Look around for greasy waste, hot coals, matches, or anything which
could fire the building.
Q. What would you do if you had a plant in good working order?
A. Keep it so, and let well enough alone.
Q. Of what use is the indicator?
A. The indicator is used to determine the indicated power developed by
an engine, to serve as a guide in setting valves and showing the action
of the steam in the cylinder.
Q. How would you increase the power of an engine?
A. To increase the power of an engine, increase the speed; or get
higher pressure of steam, use less expansion.
Q. How do you find the horsepower of an engine?
A. Multiply the speed of piston in feet per minute by the total
effective pressure upon the piston in pounds and divide the product by
33,000.
Q. Which has the most friction, a perfectly fitted, or an imperfectly
fitted valve or bearing?
A. An imperfect one.
Q. How hot can you get water under atmospheric pressure with exhaust
steam?
A. 212 degrees.
Q. Does pressure have any influence on the boiling point?
A. Yes.
Q. Which do you think is the best economy, to run with your throttle
wide open or partly shut?
A. Always have the throttle wide open on a governor engine.
Q. At what temperature has iron the greatest tensile strength?
A. About 600 degrees.
Q. In what position on the shaft does the eccentric stand in relation
to the crank?
A. The throw of the eccentric should always be in advance of the crank
pin.
Q. About how many pounds of water are required to yield one horsepower
with our best engines?
A. From 25 to 30.
Q. What is meant by atmospheric pressure?
A. The weight of the atmosphere.
Q. What is the weight of atmosphere at sea level?
A. 14.7 pounds.
Q. What is the coal consumption per hour per indicated horsepower?
A. Varies from one and a half to seven pounds.
Q. What is the consumption of coal per hour on a square foot of grate
surface?
A. From 10 to 12 pounds.
Q. What is the water consumption in pounds per hour per indicated
horsepower?
A. From 25 to 60 pounds.
Q. How many pounds of water can be evaporated with one pound of best
soft coal?
A. From 7 to 10 pounds.
Q. How much steam will one cubic inch of water evaporate under
atmospheric pressure?
A. One cubic foot of steam (approximately).
Q. What is the weight of a cubic foot of fresh water?
A. Sixty-two and a half pounds.
Q. What is the weight of a cubic foot of iron?
A. 486.6 pounds.
Q. What is the weight of a square foot of one-half inch boiler plate?
A. 20 pounds.
Q. How much wood equals one ton of soft coal for steam purposes?
A. About 4,000 pounds of wood.
Q. How long have you run engines?
Q. Have you ever done your own firing?
Q. What is the source of all power in the steam engine?
A. The heat stored up in the coal.
Q. How is the heat liberated from the coal?
A. By burning it; that is, by combustion.
Q. Of what does coal consist?
A. Carbon, hydrogen, nitrogen, sulphur, oxygen and ash.
Q. What are the relative proportions of these that enter into coal?
A. There are different proportions in different specimens of coal, but
the following shows the average per cent: Carbon, 80; hydrogen, 5;
nitrogen, 1; sulphur, 2; oxygen, 7; ash, 5.
Q. What must be mixed with coal before it will burn?
A. Atmospheric air.
Q. What is air composed of?
A. It is composed of nitrogen and oxygen in the proportion of 77 of
nitrogen to 23 of oxygen.
Q. What parts of the air mix with what parts of the coal?
A. The oxygen of the air mixes with the carbon and hydrogen of the coal.
Q. How much air must mix with the coal?
A. 150 cubic feet of air for every pound of coal.
Q. How many pounds of air are required to burn one pound of carbon?
A. Twelve.
Q. How many pounds of air are required to burn one pound of hydrogen?
A. Thirty-six.
Q. Is hydrogen hotter than carbon?
A. Yes, four and one-half times hotter.
Q. What part of the coal gives out the most heat?
A. The hydrogen does part for part, but as there is so much more of
carbon than hydrogen in the coal we get the greatest amount of heat
from carbon.
Q. In how many different ways is heat transmitted?
A. Three; by radiation, by conduction and by convection.
Q. If the fire consisted of glowing fuel, show how the heat enters the
water and forms steam?
A. The heat from the glowing fuel passes by radiation through the air
space above the fuel to the furnace crown. There it passes through the
iron of the crown by conduction. There it warms the water resting on
the crown, which then rises and parts with its heat to the colder water
by conduction till the whole mass of water is heated. Then the heated
water rises to the surface and parts with its steam, so a constant
circulation of water is maintained by convection.
Q. What does water consist of?
A. Oxygen and hydrogen.
Q. In what proportion?
A. Eight of oxygen to one of hydrogen by weight.
Q. What are the different kinds of heat?
A. Latent heat, sensible heat and sometimes total heat.
Q. What is meant by latent heat?
A. Heat that does not affect the thermometer and which expands itself
in changing the nature of a body, such as turning ice into water or
water into steam.
Q. Under what circumstances do bodies get latent heat?
A. When they are passing from a solid state to a liquid or from a
liquid to a gaseous state.
Q. How can latent heat be recovered?
A. By bringing the body back from a state of gas to a liquid or from
that of a liquid to that of a solid.
Q. What is meant by a thermal unit?
A. The heat necessary to raise one pound of water at 39 degrees Fn. 1
degree Fahrenheit.
Q. If the power is in coal, why should we use steam?
A. Because steam has some properties which make it an invaluable agent
for applying the energy of the heat to the engine.
Q. What is steam?
A. It is an invisible elastic gas generated from water by the
application of heat.
Q. What are its properties which make it so valuable to us?
A. 1.--The ease with which we can condense it. 2.--Its great expansive
power. 3.--The small space it occupies when condensed.
Q. Why do you condense the steam?
A. To form a vacuum and so destroy the back pressure that would
otherwise be on the piston and thus get more useful work out of the
steam.
Q. What is vacuum?
A. A space void of all pressure.
Q. How do you maintain a vacuum?
A. By the steam used being constantly condensed by the cold water or
cold tubes, and the air pump as constantly clearing the condenser out.
Q. Why does condensing the used steam form a vacuum?
A. Because a cubic foot of steam, at atmospheric pressure, shrinks into
about a cubic inch of water.
Q. What do you understand by the term horse power?
A. A horse power is equivalent to raising 33,000 pounds one foot per
minute, or 550 pounds raised one foot per second.
Q. How do you calculate the horse power of tubular or flue boilers?
A. For tubular boilers, multiply the square of the diameter by length,
and divide by four. For flue boilers, multiply the diameter by the
length and divide by four; or, multiply area of grate surface in square
feet by 1½.
Q. What do you understand by lead on an engine’s valve?
A. Lead on a valve is the admission of steam into the cylinder before
the piston completes its stroke.
Q. What is the clearance of an engine as the term is applied at the
present time?
A. Clearance is the space between the cylinder head and the piston head
with the ports included.
Q. What are considered the greatest improvements on the stationary
engine in the last forty years?
A. The governor, the Corliss valve gear and the triple compound
expansion.
Q. What is meant by triple expansion engine?
A. A triple expansion engine has three cylinders using the steam
expansively in each one.
Q. What is a condenser as applied to an engine?
A. The condenser is a part of the low pressure engine and is a
receptacle into which the exhaust enters and is there condensed.
Q. What are the principles which distinguish a high pressure from a low
pressure engine?
A. Where no condenser is used and the exhaust steam is open to the
atmosphere.
Q. About how much gain is there by using the condenser?
A. 17 to 25 per cent where cost of water is not figured.
Q. What do you understand by the use of steam expansively?
A. Where steam admitted at a certain pressure is cut off and allowed to
expand to a lower pressure.
Q. How many inches of vacuum give the best results in a condensing
engine?
A. Usually considered 25.
Q. What is meant by a horizontal tandem engine?
A. One cylinder being behind the other with two pistons on same rod.
Q. What is a Corliss valve gear?
A. (_Describe the half moon or crab claw gear, or oval arm gear with
dash pots._)
Q. From what cause do belts have the power to drive shafting?
A. By friction or cohesion.
Q. What do you understand by lap?
A. Outside lap is that portion of valve which extends beyond the ports
when valve is placed on the center of travel, and inside lap is that
portion of valve which projects over the ports on the inside or towards
the middle of valve.
Q. What is the use of lap?
A. To give the engine compression.
Q. Where is the dead center of an engine?
A. The point where the crank and the piston rod are in the same right
line.
Q. What is the tensile strength of American boiler iron?
A. 40,000 to 60,000 pounds per square inch.
Q. What is very high tensile strength in boiler iron apt to go with?
A. Lack of homogeneousness and lack of toughness.
Q. What is the advantage of toughness in boiler plate?
A. It stands irregular strains and sudden shocks better.
Q. What are the principal defects found in boiler iron?
A. Imperfect welding, brittleness, low ductility.
Q. What are the advantages of steel as a material for boiler plates?
A. Homogeneity, tensile strength, malleability, ductility and freedom
from laminations and blisters.
Q. What are the disadvantages of steel as a material for boiler plates?
A. It requires greater skill in working than iron, and has, as bad
qualities, brittleness, low ductility and flaws induced by the pressure
of gas bubbles in the ingot.
Q. When would you oil an engine?
A. Before starting it and as often while running as necessary.
Q. How do you find proper size of any stay bolts for a well made boiler?
A. First, multiply the given steam pressure per square inch by the
square of the distance between centers of stay bolts, and divide the
product by 6,000, and call the answer “the quotient.” Second, divide
“the quotient” by .7854, and extract the square root of the last
quotient; the answer will give the required diameter of stay bolts at
the bottom of thread.
Q. In what position would you place an engine, to take up any slack
motion of the reciprocating parts?
A. Place engine in the position where the least wear takes place on
the journals. That is, in taking up the wear of the crank-pin brasses,
place the engine on either dead center, as, when running, there is
but little wear upon the crank-pin at these points. If taking up
the cross-head pin brasses--without disconnecting and swinging the
rod--place the engine at half stroke, which is the extreme point
of swing of the rod, there being the least wear on the brasses and
cross-head pin in this position.
Q. What benefits are derived by using flywheels on steam engines?
A. The energy developed in the cylinder while the steam is doing its
work is stored up in the flywheel, and given out by it while there is
no work being done in the cylinder--that is, when the engine is passing
the dead centers. This tends to keep the speed of the engine shaft
steady.
Q. Name several kinds of reducing motions, as used in indicator
practice?
A. The pantograph, the pendulum, the brumbo pulley, the reducing wheel.
Q. How can an engineer tell from an indicator diagram whether the
piston or valves are leaking?
A. Leaky steam valves will cause the expansion curve to become convex;
that is, it will not follow hyperbolic expansion, and will also show
increased back pressure. But if the exhaust valves leak also, one may
offset the other, and the indicator diagram would show no leak.
A leaky piston can be detected by a rapid falling in the pressure on
the expansion curve immediately after the point of cut-off. It will
also show increased back pressure.
A falling in pressure in the upper portion of the compression curve
shows a leak in the exhaust valve.
Q. What would be the best method of treating a badly scaled boiler,
that was to be cleaned by a liberal use of compound?
A. First open the boiler up and note where the loose scale, if any,
has lodged. Wash out thoroughly and put in the required amount of
compound. While the boiler is in service, open the blow-off valve for a
few seconds, two or three times a day, to be assured that it does not
become stopped up with scale.
After running the boiler for a week, shut it down, and, when the
pressure is down and the boiler cooled off, run the water out and take
off the hand-hole plates. Note what effect the compound has had on the
scale, and where the disengaged scale has lodged. Wash out thoroughly
and use judgment as to whether it is advisable to use a less or greater
quantity of compound, or to add a small quantity daily.
Continue the washing out at short intervals, as many boilers have been
burned by large quantities of scale dropping on the crown sheets and
not being removed.
Q. If a condenser was attached to a side-valve engine, that had been
set to run non-condensing, what changes, if any, would be necessary?
A. More lap would have to be added to the valve to cut off the steam
at an earlier point of the stroke; if not, the initial pressure into
the cylinder would be throttled down and the economy, to be gained from
running condensing, lessened.
Q. If you are carrying a vacuum equal to 27½ inches of mercury, what
should the temperature of the water in the hot well be?
A. 108 degrees Fahrenheit.
Q. Define specific gravity.
A. The specific gravity of a substance is the number which expresses
the relation between the weights of equal volume of that substance, and
distilled water of 60 degrees Fahrenheit.
Q. Find the specific gravity of a body whose volume is 12 cubic inches,
and which floats in water with 7 cubic inches immersed.
A. When a body floats in water, it displaces a quantity of water equal
to the weight of the floating body. Thus, if a body of 12 cubic inches
in volume floats with 7 cubic inches immersed, 7 cubic inches of water
must be equal in weight to 12 cubic inches of the substance and one
cubic inch of water to twelve-sevenths cubic inches of the substance.
As specific gravity equals weight of one volume of substance divided by
weight of equal volume of water, then specific gravity of the substance
in this case equals 1 divided by twelve-sevenths.
USEFUL INFORMATION.
To find circumference of a circle, multiply diameter by 3.1416.
To find diameter of a circle, multiply circumference by .31831.
To find area of a circle multiply square of diameter by .7854.
To find area of a triangle, multiply base by one-half the perpendicular
height.
To find surface of a ball, multiply square of diameter by 3.1416.
To find solidity of a sphere, multiply cube of diameter by .5236.
To find side of an equal square, multiply diameter by .8862.
To find cubic inches in a ball multiply cube of diameter by .5236.
Doubling the diameter of a pipe increases its capacity four times.
A gallon of water (U. S. standard) weighs 8 1-3 pounds and contains 231
cubic inches.
A cubic foot of water contains 7½ gallons, 1728 cubic inches, and
weighs 62½ pounds.
To find the pressure in pounds per square inch of a column of water
multiply the height of the column in feet by .434.
Steam rising from water at its boiling point (212 degrees) has a
pressure equal to the atmosphere (14.7 pounds to the square inch).
A standard horse power: The evaporation of 30 lbs. of water per hour
from a feed water temperature of 100 degrees F. into steam at 70 lbs.
gauge pressure.
To find capacity of tanks any size; given dimensions of a cylinder in
inches, to find its capacity in U. S. gallons: Square the diameter,
multiply by the length and by .0034.
To ascertain heating surface in tubular boilers, multiply two-thirds of
the circumference of boiler by length of boiler in inches and add to it
the area of all the tubes.
One-sixth of tensile strength of plate multiplied by thickness of plate
and divided by one-half the diameter of boiler gives safe working
pressure for tubular boilers. For marine boilers add 20 per cent for
drilled holes.
To find the horsepower of an engine, the following four factors must
be considered: Mean effective or average pressure on the cylinder,
length of stroke, diameter of cylinder, and number of revolutions per
minute. Find the area of the piston in square inches by multiplying
the diameter by 3.1416 and multiply the result by the steam pressure
in pounds per square inch; multiply this product by twice the product
of the length of the stroke in feet and the number of revolutions
per minute; divide the result by 33,000, and the result will be the
horsepower of the engine.
(Theoretically a horsepower is a power that will raise 33,000 pounds
one foot in one minute.)
The power of fuel is measured theoretically from the following basis:
If a pound weight fall 780 feet in a vacuum, it will generate heat
enough to raise the temperature of one pound of water one degree.
Conversely, power that will raise one pound of water one degree in
temperature will raise a one pound weight 780 feet. The heat force
required to turn a pound of water at 32 degrees into steam would lift
a ton weight 400 feet high, or develop two-fifths of one horsepower
for an hour. The best farm engine practically uses 35 pounds of water
per horsepower per hour, showing that one pound of water would develop
only one-thirty-fifth of a horsepower in an hour, or 7 1-7 per cent of
the heat force liberated. The rest of the heat force is lost in various
ways, as explained in the body of this book.
The following[9] will assist in determining the amount of power
supplied to an engine:
Footnote 9: J. H. Maggard in “Rough and Tumble Engineering.”
“For instance, a 1-inch belt of the standard grade with the proper
tension, neither too tight or too loose, running at a maximum speed of
800 feet a minute will transmit one horsepower, running 1,600 feet two
horsepower and 2,400 feet three horsepower. A 2-inch belt at the same
speed, twice the power.
“Now if you know the circumference of your flywheel, the number of
revolutions your engine is making and the width of belt, you can figure
very nearly the amount of power you can supply without slipping your
belt. For instance, we will say your flywheel is 40 inches in diameter
or 10.5 feet nearly in circumference and your engine was running 225
revolutions a minute, your belt would be traveling 225×10.5 feet =
2362.5 feet, or very nearly 2,400 feet, and if one inch of belt would
transmit three horsepower running this speed, a 6-inch belt would
transmit eighteen horsepower, a 7-inch belt twenty-one horsepower, an
8-inch belt twenty-four horsepower, and so on. With the above as a
basis for figuring you can satisfy yourself as to the power you are
furnishing. To get the best results a belt wants to sag slightly, as it
hugs the pulley closer, and will last much longer.”
KEYING PULLEYS.[10]
A key must be of equal width its whole length and accurately fit the
seats on shaft and in pulley. The thickness should vary enough to make
the taper correspond with that of the seat in the pulley. The keys
should be driven in tight enough to be safe against working loose. The
hubs of most of the pulleys on the machine run against the boxes, and
in keying these on, about 1-32 of an inch end play to the shaft should
be allowed, because there is danger of the pulley rubbing so hard
against the end of the box as to cause it to heat.
A key that is too thin but otherwise fits all right can be made tight
by putting a strip of tin between the key and the bottom of the seat in
the pulley.
_Drawing Keys._ If a part of the key stands outside of the hub, catch
it with a pair of horseshoe pinchers and pry with them against the hub,
at the same time hitting the hub with a hammer so as to drive pulley
on. A key can sometimes be drawn by catching the end of it with a claw
hammer and driving on the hub of pulley. If pulley is against box and
key cut off flush with hub, take the shaft out and use a drift from the
inside, or if seat is not long enough to make this possible, drive the
pulley on until the key loosens.
BABBITTING BOXES.[10]
To babbitt any kind of a box, first chip out all of the old babbitt
and clean the shaft and box thoroughly with benzine. This is necessary
or gas will be formed from the grease when the hot metal is poured in
and leave “blow holes.” In babbitting a _solid box_ cover the shaft
with paper, draw it smooth and tight, and fasten the lapped ends with
mucilage. If this is not done the shrinkage of the metal in cooling
will make it fast on the shaft, so that it can’t be moved. If this
happened it would be necessary to put the shaft and box together in
the fire and melt the babbitt out or else break the box to get it off.
Paper around the shaft will prevent this and if taken out when the
babbitt has cooled the shaft will be found to be just tight enough to
run well.
Footnote 10: Courtesy J. I. Case Threshing Machine Co., from “Science
of Successful Threshing.”
Before pouring the box, block up the shaft until it is in line and in
center of the box and put stiff putty around the shaft and against
the ends of the box to keep the babbitt from running out. Be sure to
leave air-holes at each end at the top, making a little funnel of putty
around each. Also make a larger funnel around the pouring hole, or,
if there is none, enlarge one of the air-holes at the end and pour in
that. The metal should be heated until it is just hot enough to run
freely and the fire should not be too far away. When ready to pour the
box, don’t hesitate or stop, but pour continuously and rapidly until
the metal appears at the air holes. The oil hole may be stopped with a
wooden plug and if this plug extends through far enough to touch the
shaft, it will leave a hole through the babbitt so that it will not be
necessary to drill one.
_A split box_ is babbitted in the same manner except that strips of
cardboard or sheet-iron are placed between the two halves of the box
and against the shaft to divide the babbitt. To let the babbitt run
from the upper half to the lower, cut four or six V-shaped notches, a
quarter of an inch deep, in the edges of the sheet-iron or cardboard
that come against the shaft. Cover the shaft with paper and put
cardboard liners between the box to allow for adjustment as it wears.
Bolt the cap on securely before pouring. When the babbitt has cooled,
break the box apart by driving a cold chisel between the two halves.
Trim off the sharp edges of the babbitt and with a round-nose chisel
cut oil grooves from the oil hole towards the ends of the box and on
the slack side of the box or the one opposite to the direction in which
the belt pulls.
The ladle should hold six or eight pounds of metal. If much larger it
is awkward to handle and if too small it will not keep the metal hot
long enough to pour a good box. The cylinder boxes on the separator
take from two to three pounds of metal each. If no putty is at hand,
clay mixed to the proper consistency may be used. Use the best babbitt
you can get for the cylinder boxes. If not sure of the quality, use
ordinary zinc. It is not expensive and is generally satisfactory.
MISCELLANEOUS.
Lime may be taken out of an injector by soaking it over night in a
mixture of one part of muriatic acid and ten parts soft water. If a
larger proportion of acid is used it is likely to spoil the injector.
A good blacking for boilers and smokestacks is asphaltum dissolved in
turpentine.
To polish brass, dissolve 5 cents’ worth of oxalic acid in a pint of
water and use to clean the brass. When tarnish has been removed, dry
and polish with chalk or whiting.
It is said that iron or steel will not rust if it is placed for a few
minutes in a warm solution of washing soda.
Grease on the bottom of a boiler will stick there and prevent the water
from conducting away the heat. When steel is thus covered with grease
it will soon melt in a hot fire, causing a boiler to burst if the steel
is poor, or warping it out of shape if the steel is good.
Sulphate of lime in water, causing scale, may be counteracted and scale
removed by using coal oil and sal soda. When water contains carbonate
of lime, molasses will remove the scale.
CODE OF WHISTLE SIGNALS.
One short sound means to stop.
Two short sounds means the engine is about to begin work.
Three medium short sounds mean that the machine will soon need grain
and grain haulers should hurry.
One rather long sound followed by three short ones means the water is
low and water hauler should hurry.
A succession of short, quick whistles means distress or fire.
WEIGHT PER BUSHEL OF GRAIN.
The following table gives the number of pounds per bushel required by
law or custom in the sale of grain in the several states:
====================+==+==+==+==+==+==+==+==+==+==+==
| | | | | | | | | S| |
| | | | | | | | | h| |
| | | | | | | | | e| |
| | | B| | | | | | l| |
| | | u| | | | | | l| |
| | | c| | | | | | e| T|
| B| | k| C| | M| | | d| i|
| a| B| w| l| | i| | | | m| W
| r| e| h| o| F| l| O| | C| o| h
| l| a| e| v| l| l| a| R| o| t| e
| e| n| a| e| a| e| t| y| r| h| a
| y| s| t| r| x| t| s| e| n| y| t
| .| .| .| .| .| .| .| .| .| .| .
--------------------+--+--+--+--+--+--+--+--+--+--+--
Arkansas |48|60|52|60|..|..|..|56|56|45|60
California |50|..|40|..|..|..|32|54|52|..|60
Connecticut |..|..|45|..|..|..|32|56|56|..|56
District of Columbia|47|62|48|60|..|..|32|56|56|45|60
Georgia |40|..|..|60|..|..|35|56|56|45|60
Illinois |48|60|52|60|56|45|32|56|56|..|60
Indiana |48|60|50|60|..|..|32|56|56|45|60
Iowa |48|60|52|60|56|48|32|56|56|45|60
Kansas |50|60|50|..|..|..|32|56|56|45|60
Kentucky |48|60|52|60|56|..|32|56|56|45|60
Louisiana |32|..|..|..|..|..|32|..|56|..|60
Maine |48|64|48|..|..|..|30|..|56|..|60
Manitoba |48|..|48|60|56|34|..|56|56|..|60
Maryland |48|64|48|..|..|..|32|56|56|45|60
Massachusetts |48|48|..|..|..|..|32|56|56|..|60
Michigan |48|..|48|60|56|..|32|56|56|45|60
Minnesota |48|60|42|60|..|48|32|56|56|..|60
Missouri |48|60|52|60|56|50|32|56|56|45|60
Nebraska |48|60|52|60|..|..|34|56|56|45|60
New York |48|62|48|60|..|..|32|56|58|44|60
New Jersey |48|..|50|64|..|..|30|56|56|..|60
New Hampshire |..|60|..|..|..|..|30|56|56|..|60
North Carolina |48|..|50|64|..|..|30|56|54|..|60
North Dakota |48|..|42|60|56|..|32|56|56|..|60
Ohio |48|60|50|60|..|..|32|50|56|45|60
Oklahoma |48|..|42|60|56|..|32|56|56|..|60
Oregon |46|..|42|60|..|..|36|56|56|..|60
Pennsylvania |47|..|48|62|..|..|30|56|56|..|60
South Dakota |48|..|52|60|56|50|32|56|56|..|60
South Carolina |48|60|56|60|..|..|33|56|56|..|60
Vermont |48|64|48|..|60|..|32|56|56|42|60
Virginia |48|60|48|64|..|..|32|56|56|45|60
West Virginia |48|60|52|60|..|..|32|56|56|45|60
Wisconsin |48|..|48|60|..|..|32|56|56|..|60
--------------------+--+--+--+--+--+--+--+--+--+--+--