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i
FOUNDRY WORK
FOUNDRY WORK
A Text on Molding, Dry-sand Core-Making,
and the Melting and Mixing of Metals
R. E: WENDT
Head Instructor in Foundry Practice, Purdue University ; Member of
American Foundrymens Association and the Society for
the Promotion of Engineering Education
First Edition
Third Impression
McGRAW-HILL BOOK COMPANY, Inc.
NEW YORK: 370 SEVENTH AVENUE
LONDON: 6 & 8 BOUVERIE ST., E. C. 4
1923
TS
Copyright, 1923, by the
McGraw-Hill Book Company, Inc.
PRINTED IN THE UNITED STATES OF AMERICA
PREFACE
In preparing this book, it has been the author's aim to
provide a suitable text for schools and colleges and for
use by apprentices in commercial shops. It is elementary
to the extent that the student can grasp the fundamental
principles of foundry work, yet deep enough to give a
general working knowledge of foundry practice.
The book consists of three parts. The first will enable
the student to secure a general knowledge of foundry work,
of the sizes and types of blast furnaces, and of the making
of pig iron.
The second provides instructions for practice in molding,
coremaking and other parts of foundry work.
The third part is devoted to the mixing and melting of
metals.
The material contained in this volume was obtained as
a direct result of the author's experience in teaching
apprentices in commercial shops and engineering students
at Purdue University. The information on making coke,
mining iron ore, operating blast furnaces, and chemical
analysis of iron has been inserted to round out the volume
and represents good commercial, practice.
For many of the drawings the author is indebted to
students taking foundry work under him, and for other
illustrations to foundry supply firms.
R. E. Wendt.
W. Lafayette, Ixd.
June, 1923.
^77S
CONTENTS
PAGE
Preface v
PART I
FUNDAMENTAL PRINCIPLES
CHAPTER I
Foundry Cokes 1
Iron Ores — The Blast Furnace.
CHAPTER II
Commercial Foundry Layout 8
Foundry Product and Branches of Molding.
CHAPTER III
Molding Sand 13
Composition and Selecting of Sand, Tempering and Caring
for Sand.
CHAPTER IV
Ramming the Sand 16
Venting the Mold — Facing for Molds — Parting Materials.
CHAPTER V
Flasks 21
Molding and Bottom Boards — Clamps and Weights.
CHAPTER \T
Gating Molds , 29
CHAPTER VH
Shrinkage 34
Churning — Breaking Gates and Feeders from Castings.
CHAPTER VIII
Gaggers 41
Setting Cross Bars and Gaggers — Chaplets — Setting Chap-
lets, Wedges.
vii
viii CONTENTS
PAGE
CHAPTER IX
Tools 48
Questions on Part I 51
PART II
EXERCISES AND PROBLEMS
CHAPTER X
Bench Molding and Molding Exercises 55
Exercises: No. 1, Face Plate; No. 2, Hexagonal Nut; No. 3,
Ball Handle; No. 4, Oil Drip Cup; No. 5, Split Pattern of
Collar; No. 6, Split Pulley; No. 7, Governor Pulley; No. 8,
Sheave Wheel; No. 9, Bevel Gear Blank; No. 10, Embed-
ding Face Plate; No. 11, Thinning a Plate; No. 12, Making
Pulley Longer than Pattern.
CHAPTER XI
Floor Molding Exercises 82
Exercises: No. 13, Cone Pulley; No. 14, Flywheel; No. 15,
Sugar Kettle; No. 16, Steam Engine Piston; No. 17, Lathe
Bed; No. 18, Machine Base; No. 19, Lifting Dry-sand Core
out of Pattern; No. 20, Open-sand Mold; No. 21, Sweep
Molding— Pit Molding— Problems.
CHAPTER XII
Metal Patterns, Follow Boards, Match-Plates 120
CHAPTER XIII
Molding Machines 127
CHAPTER XIV
Dry-sand Core Making 132
Exercises: No. 1, Round Cores; No. 2, Cone Pulley Core;
Plates — Ramming — ^^enting Cores — Rodding Cores — Lifting
Hooks— Pasting and Daubing Cores— Core Ovens and Bak-
ing — Core Making Benches.
CHAPTER XV
Exercises in Dry Sand Core Making 142
Exercises: No. 1, Round Cores; No. 2, Cone Pulley Core;
No. 3, Lathe Bed Core; No. 4, Machine Base Core; No. 5,
Making Core with Pattern— Coremaking Machines.
Questions on Part II 148
CONTENTS ix
PART III
MELTING AND MIXING METALS
-^ — PAGE
CHAPTER XVI
Furnaces, General C onstruction of Cupola . Tuyeres, Cupola
Linings and Lining the Cupola 153
General Construction of Cupola — Sizes of Cupolas — Tuy-
eres—Cupola Linings— Lining the Cupola— Ladles — Blowers
and Fans.
CHAPTER XVn
Preparing, Charging and Operating the Cupola 164
CHAPTER XVin
Record Forms 174
CHAPTER XIX
Foundry Irons 178
Mixing Irons by Fracture and Chemical Analysis — General
Purpose Mixtures— Testing Gray Cast Iron.
CHAPTER XX
Non-ferrous Metal Founding 187
Alloying Non-ferrous Metals.
Questions on Part III 195
Tables 197
Foundry Books for General Reading 198
Glossary of Foundry Terms 199
Index 203
PART I
FUNDAMENTAL PRINCIPLES
FOUNDRY WORK
CHAPTER I
FOUNDRY COKES
There are two methods of manufacturing the coke used
for melting metals. They are known as the Beehive-oven
and By-product, or Retort, methods. The beehive method
is the older and until recently the leading method.
In the beehive process the air is admitted to the coking
chamber for the purpose of burning all the volatile products
of the coal. There is left a hard coke, silvery in appear-
ance, good for melting metals. However, all the other
products of the coal are wasted, and for that reason the
beehive method is being replaced rapidly by the by-product
method.
In the manufacture of by-product coke, almost all of
the useful ingredients in the coal are saved, yet the coke
is of good quality for melting purposes. The by-product
coke is darker than coke made by the beehive process and
frequently is not so hard. When the two cokes are used
for melting metals there seems to be very little difference
between them.
A beehive oven is shown in Fig 1, A indicating the fur-
nace, B the charging level, C the receiving level, D the
receiving door, E the charging hole, and F the car tracks.
These ovens are built in sizes ranging from 10 to 12 ft. in
diameter and from 6 to 8 ft. high. The inside of the oven
is made of fire brick and the outside of stone.
Bituminous coal is dumped into the oven from the top to
a depth of about 2 ft. for 48-hr. coke or 21/2 ft. for 72-hr.
coke. From 3 to 7 tons of coke are made every time the
3
4 FOUNDRY WORK
oven is fired, the amount depending upon the size of the
oven. After the impurities are burned off, the coke is
drawn out and cooled with water. From 60 to 70 per cent
of the coal charged is obtained as coke. The analysis of
a good foundry coke should be as follows: Carbon from
88 to 92 per cent, ash from 6 to 10 per cent, and sulphur
not over 1 per cent (as low as possible).
Although beehive-oven and by-product cokes are almost
always used for melting metals, both can be used for heat-
ing purposes.
/;^j^f^^^--^&^m\v
Fig. 1. — Beehive coke oven.
IRON ORES
Iron ore is found in many parts of the United States.
The largest iron-ore district is known as the Lake Superior
district. The mines are scattered over the northern part
of Michigan, Wisconsin, and Minnesota. About four-fifths
of the iron mined is obtained in this region, and the ores
are known as northern ores. The district next in size is
known as the Birmingham district. It is located in the
southern part of the country, and its ores are called south-
ern ores.
There are many varieties of iron ore. The ores most
frequently used are known as the red and brown hematites.
FOUNDRY COKES 5
The red hematite ore is used more than the brown hematite
or any other ore. Magnetite and carbonate are used, but
very little in comparison with the red hematite. The ores
generally used to make pigs for gray-iron castings contain
from 50 to 70 per cent of iron. An ore that contains less
than 30 per cent is seldom used. The pig iron that the
founder uses generally contains from 92 to 96 per cent of
metallic iron.
THE BLAST FURNACE
The blast furnace, shown in Fig. 2, is used to extract
iron from the ore, and the iron thus produced, called pig
iron, is run into forms known commercially as pigs. All
the iron that is used commercially is first passed through
such a furnace.
The size of the furnace varies in diameter from 20 to 35
ft., and in height from 100 to 125 feet. Fire brick and fire
clay are used as linings. The bricks are made of silica,
carbon, ganister, coke, magnesia and asbestos. About 450
tons of fire brick and 60 tons of fire clay are required to
line a furnace of the size shown in the illustration. Four
brick masons and twelve helpers are needed for approxi-
mately 30 days to do the work. A space from 4 to 5 in.
wide, between the bricks and the shell, is filled with granu-
lated furnace slag mixed with water.
From 1 to 2 weeks' time is required for the lining to dry.
It is claimed that the lining will last for about 5 years
under continuous operation. After the furnace has run
a short time, the lining becomes protected by a carbona-
ceous concrete from 2 to 12 in. thick.
The furnace is charged from the top. All material is
dumped into what is known as the bell, indicated by C,
Fig. 2. From the bell the charge is dumped into the fur-
nace. The separate charges are made up of about 800 lb.
of ore, 450 lb. of coke, and 160 lb. of limestone. About
100 tons of coke, 160 tons of ore, and 35 tons of limestone
(530 tons in all) passes through a furnace of the size shown
6
FOUNDRY WORK
in 24 hours. It is considered that a ton of coke is required
to make one ton of pig iron. The metal is drawn out at the
;^^/:^V4:.;v^,^/
^py^^^
Fig. 2. — Blast furnace.
bottom of the furnace through the tap hole A, and the slag
is run out through the slag hole B. The slag hole is located
directly opposite and a little higher than the tap hole.
FOUNDRY COKES 7
It is claimed by some blast furnace men that when a
furnace is working hot the iron is high in silicon, and that
when the furnace is working cold the iron is high in sulphur.
When the slag is dark and dense, it is generally considered
that the silicon content is low and the sulphur content high.
From 600 to 1,000 lb. of slag are produced to every ton
of iron.
The air used for draft in the blast furnace is heated to
about 1,100 deg. F. and is blown into the furnace under a
pressure of from 6 to 24 lb.
There are usually four stoves used to heat the blast.
While one is in operation the other three are being heated.
The stoves are from 18 to 24 ft. in diameter and from 24
to 40 ft. high. The inside of a stove is made with a checker
work of brick. The stoves are heated by the blast furnace
gases.
When sand-cast pig iron is made, there are generally
two casting floors to a casting house. The sand beds are
from 2 to 3 ft. deep. Long channels are made in the beds
and the metal is poured into the channels to cool. While
a tap is solidifying in one bed, the other bed is run full
from the next tap. Furnaces of the size mentioned are
tapped about five times in 24 hr., a schedule that allows
for removing 40 tons of metal from the casting floor after
each tap. After the pig bed is run full and the metal has
solidified, sand is thrown over the iron to a depth of about
1 in. Then men having shoes with wooden soles about l^^
in. thick walk over the iron, break it up into pigs, and
remove it from the casting floor. It is analyzed and graded
according to chemical composition. When used for making
gray-iron castings it is known as Nos. 1, 2, 3, 4, and 5
pig iron.
Pig-casting machines have come into use in recent
years. They are known as the E. A. Vehling, R. W. Davis,
and H. R. Geer machines.
CHAPTER II
COMMERCIAL FOUNDRY LAYOUT
A typical commercial foundry is shown in Fig. 3. The
building is 56 x 84 ft. and has the features that are common
to all commercial foundries.
Molding Room. — The molding room is 52 x 56 ft. The
heap of molding sand with one-half of the space between
it and the next heaps is called a floor. From 12 to 24
molders can work in such a room at one time, the number
depending upon the class of castings made. In the morning,
the molder begins work on one end of the heap, say the end
which is furthermost from the outer wall, and by the time
the iron is ready to pour in the afternoon, the floor is filled
with molds. After the molds have been poured they are
shaken out, the castings sent to the cleaning room, and the
sand prepared for the next day's work. Castings that are
too hot to handle are left in the sand until the next morn-
ing, or until they have cooled. The conveying of materials
such as molds, castings and melted iron about the room is
done by means of trucks, overhead trolleys, or cranes which
run on tracks. The trolleys, trucks and cranes are oper-
ated by electric motors in some shops, while in others the
workmen push or pull them from place to place.
Pattern Storage. — Since processes of molding require
patterns, foundries very quickly accumulate great quan-
tities that require storage. The pattern storage room in
this shop is shown in the upper right hand corner of the
sketch, surrounding the office. One man is in charge. The
patterns are stored on shelves, one above the other, from
floor to ceiling, and each pattern is numbered and regis-
tered on a card index list. Patterns are withdrawn for
8
COMMERCIAL FOUNDRY LAYOUT
9
foundry use and when the work is finished they are cleaned
and returned to the pattern storage room.
Core Room. — In the lower left hand corner is the core
room, containing all the apparatus for the making of cores
and the core oven for drying them. Core boxes and other
XmTmJsromn
?4xl0 I
0' 5' 10 15' 20 25
"ffaHlers
Cinder Mill-' Scales " Elevaiop
RAILROAD SIDING
1^
1?
I"*
is
Fig. 3. — Typical layout for small foundry.
materials relating to core making are stored in the pattern
storage room.
Cupola Room. — Next to the core room is the cupola
room. It is in charge of the cupola tender and has to do
with the charging of the cupola, the melting of the iron
and the delivering of melted iron to the ladles in the
10 FOUNDRY WORK
molding room. All iron, coke, coal and other materials
used in the cupola are weighed on the ground floor and then
taken by elevator to the charging floor, 10 to 18 ft. above
the main floor of the cupola room, from which they are
charged into the cupola.
Cleaning Room. — When the castings are taken from the
sand they are sent to the cleaning room which is shown in
the lower right corner of the building. They are dumped
into metal barrels, called rattlers, that are revolved until
the sand and dirt have been jarred from the castings,
from here they are taken to the abrasive wheels and chip-
ping benches, after which they are ready for shipment,
A side track is generally put in for switching purposes,
and coke, sand and clay sheds are built within easy reach
of the main foundry building. The iron is usually stored in
a yard close to the side track and the cupola room.
The wooden flasks generally are stored in a yard out
of doors convenient to the molding room. Iron flasks are
stored in sheds or rooms to prevent rusting.
THE FOUNDRY PRODUCT AND BRANCHES OF
MOLDING
The foundry product is castings. Some foundries make
gray-iron castings, some make steel castings, some produce
malleable iron castings, while others make brass, bronze
and aluminum castings.
Castings are produced by making molds and then filling
them with molten metal. After the metal has solidified
and the castings are cool enough to handle, the molds are
broken up and the castings are taken from the sand. Cast-
ings are made that range in weight from a few ounces to
many tons. In order to make the different sizes of castings
successfully, it has been found necessary to employ various
materials in constructing the molds.
Molding operations are classified under five general head-
ings according to the material used and the method of
COMMERCIAL FOUNDRY LAYOUT 11
working with it: Green-sand, skin-dried, dry-sand, loam,
and iron molds.
Green-sand molding is the cheapest method of making
a easting and is the one most commonly used. The name
green sand indicates that the metal is poured into the
molds while the sand is in a damp state, the same state it
was in when the mold was made.
Skin-dried molds are green-sand molds with a facing
composed of a mixture of molding sand and wheat flour
(or some other mixture) surrounding the pattern to a
thickness of 1 in. or more. Before pouring, these molds
are dried by a torch flame or some other flame on all parts
that will come into contact with the melted metal. This
eliminates the steam troubles encountered in green-sand
molding.
Dry-sand molds are made of green molding sand mixed
with a binder such as wheat flour, resin, core compound, or
linseed oil, the entire mold being baked in an oven. The
baking process drives off the moisture content of the sand,
and the binder holds the mold firmly intact during pouring.
Such a mold is usually free from steam troubles.
Loam Molds as a rule are used in the production of large
castings only. Forms, built of bricks, are plastered over
with loam mortar which is rich in clay. Skeleton patterns
and sweeps are used to shape the surface of the mold.
When the mold is completed it is thoroughly dried before
pouring.
Iron Molds. — Some molds are made of iron, the advan-
tage being that many castings can be made with each of
these molds before a replacement of the mold is necessary.
Before pouring, the molds are coated with either oil or a
graphite paint. Owing to the sizes and shapes of castings
the use of iron molds is limited.
A further division of molding is called bench molding.
Molds that are too large to be handled on a bench are made
on the floor and the process is called floor molding. Mold-
ing that requires the use of a crane in handling the molds
12 FOUNDRY WORK
is called crane molding. Large castings generally are
molded in a pit whence the term pit molding.
Holders or foundries usually specialize in one or two
branches of molding. One seldom finds a molder who
follows all branches of molding, or a foundry that makes
all classes of castings.
CHAPTER III
MOLDING SAND
Good molding sand is found along rivers and lakes in
many parts of the United States. Albany, N. Y., San-
dusky, Ohio, Ottawa, 111., and other localities are well
known to foundrymen as molding sand centers. Sand suit-
able for green-sand molding must be cohesive when mois-
tened to the proper degree of dampness and rammed to
sufficient hardness. It must stick together when the mold
is handled and must be tough enough to allow the metal
to run over it without washing or cutting into it. The
sand must be refractory enough to stand the high tem-
perature of melted cast iron (2,500 deg. F.) without fusing.
It should be porous in order to allow the free escape of
all steam and gases that are generated when the mold is
poured. The sand should be strong so that it will neither
wear out ciuickly nor crumble under heat. A good sand
will bake a little when subjected to heat.
COMPOSITION AND SELECTION OF SAND
The composition of molding sand, as given by many
chemists, is: 80 to 90 per cent silica, 6 to 10 per cent
alumina (clay), and small percentages of other ingredi-
ents such as lime, magnesia and metallic oxides.
A good foundryman is very careful when selecting mold-
ing sand, for he knows that in order to be successful in
making castings he must have sand suitable for the par-
ticular class of castings he wants to make. For small cast-
ings, requiring a smooth surface, a molding sand of fine
grain must be used. When making heavy castings a sand
of coarse grain is required to allow the steam and gas to
13
14 FOUNDRY WORK
pass out of the molds freely while the metal is solidifying.
The sand must be rammed harder for large castings than
for small. As the outside surface of a heavy casting need
not be as smooth as that of a small one, a coarse and open
grained sand is more suitable for it. If a sand suited for
light castings is used for heavy castings, there is danger of
scabbing, and at times the metal may be blown out of the
mold, since the steam and gas cannot escape. Chemical
analysis is not frequently used in the selection of molding
sand and it is best to leave the selection to some one experi-
enced along that particular line of work. One may write to
the foundry supply houses, informing them as to the class
of castings to be made, and they will give good advice as
to the kind of sand to use.
TEMPERING SAND
The tempering of sand means the mixing of the sand
with water to the proper degree of dampness. Water is
added to the sand by means of sprinkling can, hose or
water bucket. It never should be thrown on to the sand
in body or bulk that would produce mud holes, but should
be added evenly over the surface. It is best to spread the
sand out a little before wetting it.
A shovel is generally used to mix, or ''cut," the sand,
although some shops use sand mixing machinery. No mat-
ter by what method the sand is prepared, all dry and wet
parts must be mixed together evenly and all large lumps
broken up. If there is more moisture in the mold than
can be driven out when the mold is poured, the metal may
be blown out by the steam formed. When the sand is too
dry it may drop out of the flask when the mold is handled,
or the metal is likely to cut into the sand and wash it,
causing sand holes in the castings. The production of good
or bad castings often depends entirely upon the condition
of the molding sand.
When preparing sand the molder examines it by feeling
a handful. If it is too dry he adds water sparingly. If
MOLDING SAND 15
too wet he adds dry sand. By repeated test and adjust-
ment the correct consistency will be obtained. In testing
by feeling, a handful of sand is squeezed into a long lump
that is then held between the first finger and the thumb
and shaken w^ith a swift motion. If the lump does not
break, the sand is considered to be in good condition for
molding. Another test may be applied by breaking the
lump apart. If the edges remain sharp and firm after
the lump has been broken, into small pieces, it is a good
indication that the sand is in molding condition.
CARE OF SAND
When the sand is in use every day it is likely to be-
come weak, causing a great deal of trouble, not only in
making molds, but because the sand will wash when the
metal is poured. After it has been used many times the
sharp edges have become rounded, partly from wear and
partly from the high temperature of the molten metal,
and the clay has burned out. These changes are the main
causes for the weakening of sand in use. New sand, that
is, sand that has not been used for molding, is stronger
than it need be for molding and when added, makes up
for the weakening of the old sand. In this manner sand
may be used over and over without a complete replace-
ment at any time.
When shaking out molds, some of the sand will adhere to
the castings and be lost. If the amount of sand lost be re-
placed by new sand, the resulting mixture will be suitable
for molding and the molder's supply will be kept up to
normal.
After sand has been used for a time and is somewhat
burned, it will give better results than when new. Gen-
erally speaking, castings made in old sand, or sand partly
burned, will be smoother than those made in all new sand.
CHAPTER IV
RAMMING THE SAND
The sand must be rammed solidly within the flask and
around the pattern. It must be rammed firmly enough to
withstand the flow and pressure of the molten metal, and
hard enough so that the mold can be handled without hav-
ing the sand drop out of the flask. With soft ramming
the casting is likely to be larger than desired. If the mold
is soft in spots only, the casting may have bulges or lumps.
Yet sand must not be rammed harder than is necessary,
because the denser the sand, the less chance the steam and
gas have to pass through it, and because too hard ram-
ming will cause blowholes in and scabs on the castings.
There is no way to learn how hard to ram a mold except
by actual practice. At first a great deal of trouble may
be experienced, but by keeping at it with a determination
to learn, a great deal of skill may be acquired in a very
short time.
VENTING THE MOLD
There is considerable air, steam and gas in all molds,
and these must be driven out through the sand when the
mold is poured else the castings will probably be full of
blowholes. Blowholes are usually found in the part of the
casting that was uppermost when the mold was poured.
Some blowholes may be seen plainly when inspecting the
casting, but it is not uncommon for castings to be full of
small blowholes that are found only by machining.
Air is found in all molds. Steam is formed when hot
metal is poured into damp molds. When fluid metal comes
into contact with a mold (the mold may be made of either
16
RAMMING THE SAND 17
green or dn- sand) the sand next to the metal is heated to
a very high temperature and a rapid chemical reaction
takes place. This reaction liberates gases from the sand,
some of which pass into the open spaces in the mold. If
they do not escape quickly they will be caught and enclosed
by the metal, or pass to the top of the mold and prevent
the metal from filling the mold completely. At times the
gases may be confined until their increasing pressure blows
the metal from the mold with great force, an occurrence
that is dangerous to the workers.
When the ramming is done properly and a porous sand
is used, the steam, gas and air will pass out of the mold
between the grains of the sand. However, almost all molds
must be vented, which means that vent holes must be
punched into the sand to afford the steam, air and gas free
passage out of the mold. Various methods used in venting
molds will be explained when the making of molds is taken
up in detail.
FACING FOR MOLDS
Small or thin castings could be made successfully with
a fairly smooth surface if the metal were poured into a
mold that had no facing. However, if the mold is faced,
the castings are smoother than those obtained from an
unfaced mold, and usually small castings must have a
smooth skin or surface.
The facing materials mostly used for producing small
castings are Ceylon lead, East India plumbago, and soap-
stone or talc. The facing material ordinarily is put into
a small bag, and after the patterns are drawn from the
sand and the gates cut, a thin layer of the facing material
is dusted onto the surface of the mold with the bag. Rub-
bing the facing onto the surface of the mold with the hand,
or brushing it down with a camel's hair brush, will give a
smoother surface than that obtained by simply shaking
on the facing and leaving it as it falls.
When smooth castings are wanted and the mold has
18 FOUNDRY WORK
small projecting parts of sand that are likely to be knocked
off if the mold is touched with a brush, the pattern may be
replaced in the mold after the facing has been dusted on
and is tapped down. The facing is pressed into the sand
and the pattern is then withdrawn. This process of facing
a mold is known as the printing back method. Since the
facing becomes damp from the moisture in the sand, if the
pattern is left in the sand too long the facing and sand are
apt to stick to it causing the mold to be impaired or de-
stroyed when the pattern is drawn.
When heavy castings are to be produced, the part of the
mold with which the metal comes into contact should be
made from a material that is sufficiently refractory to with-
stand the high temperature of molten metal without fusing.
Molding sands are generally not refractory enough to with-
stand such high temperatures for any great length of time,
and a facing must be used which is put next to the pattern
when making the mold. The surface of the mold prepared
in this manner must also be treated by about the same
method as that explained in describing the facing of small
molds.
The facing material most commonly used for this purpose
is known as sea-coal facing. Sea-coal facing is made from
soft or bituminous coal, ground fine or coarse as desired.
The fine facing is used for small castings and the coarse
facing for large castings. The sea coal is mixed with mold-
ing sand in proportions depending upon the size or weight
of the castings and the thickness of the metal. A mixture
known as No. 10 is composed of one part of sea coal to
ten parts of sand. Usually the sand consists of 75 per
cent old molding sand and 25 per cent new molding sand,
by volume. The sand is mixed well and the sea coal is
then added. This mixture is suitable for castings having
a metal thickness of from V^ to 1 in. When the metal
thickness is greater than 1 in. a little more sea coal should
be used. Too much sea coal will cause the castings to be
rough and streaked due to the fact that the metal burns
RAMMING THE SAND 19
the facing away in places. It is seldom necessary to use
sea-coal facing on castings that are less than V2 in. thick,
but if desired, the facing should be mixed so that there is
a little less than one part of sea coal to ten parts of sand.
A good way to mix sea-coal facing is to estimate the
number of shovelfuls that will be needed to cover the pat-
tern to a depth of from i/> to 2 in. Measure the sand and
spread it out on the foundry floor, the old sand first, then
the new sand spread over the old. The sea coal should
then be spread evenly over the sand. To get a well-mixed
facing, shovel over the mixture twice and sift it through a
No. 2 riddle before tempering it. After the facing has been
sifted, sprinkle it with water and temper it in the same
manner as molding sand is tempered. The facing will then
be ready for use. It has been found that if the facing is
tramped down after the water is put on, it will mix better
and will be a little tougher than it would be if it were
merely mixed with the shovel.
PARTING MATERIALS
For almost all castings it is necessary to make molds in
parts, that is to say, one part is made on top of the other.
These parts will stick together when an attempt is made
to separate them, unless some parting material is put be-
tween them. The most common material used for this pur-
pose is called parting sand, and the sand best suited for
the work is one that has little or no clay in it.
A fine sand which is found along the shores of Lake
Michigan makes a good parting material, but some molders
prefer to use burned core sand or the burned sand that is
cleaned from the castings. Any of these sands is suitable.
There are also manufactured parting materials, known as
parting compounds, sold to the foundry trade. They are
in powder form and are used by being put into bags and
dusted onto the mold. Parting compounds give good re-
sults but cost more than parting sand and therefore are
not used as much commercially. One of the best parting
20 FOUNDRY WORK
materials known is lycopodium. This material is used when
oil has been mixed with the sand, and the only objection to
its use is its very high cost. Brick dust and powdered
charcoal also are used as parting materials, but they are
not recommended.
CHAPTER V
FLASKS
Flasks of some kind are needed for making practically
all types of molds. They may be made of wood, iron or
steel. Wooden flasks are quickly made and they are the
cheapest in first cost. Jobbing foundries use more of them
than of the other kinds because they are light in weight,
and can be altered without much work. The objections to
them are that they soon wear out and burn easily. Metal
flasks are the best where they are to be used continuously
for producing similar castings, or where altering them would
not be too expensive. With ordinary care they will last
many years without any expense other than the original
cost.
A flask consists of as many parts as are needed to make
the casting desired. When a flask has two parts, it is
called a two-part flask ; when it has three parts, it is known
as a three-part flask. A two-part flask consists of drag
and cope. A three-part flask is composed of a drag, cope
and cheek. The drag is the lower part, the cope the upper
part, and in the three-part flask, the cheek is the part be-
tween the cope and the drag. When beginning a mold,
whether the cope, drag or cheek is rammed first depends
upon the shape of the pattern. The various parts of the
flask are held in alignment by pins and sockets. The
molder should always see that the pins fit accurately in the
sockets. If they fit loosely there is likely to be a shift in
the mold. Loose pins may also cause trouble when making
a difficult lift.
Small castings usually are made in snap flasks, so called
because they have snaps or catches on one corner and
hinges on the corner diagonally opposite. They range from
21
22
FOUNDRY WORK
8 to 18 in. square in the form shown in Fig. 4, and from
10 to 20 in. in diameter in the form shown in Fig. 5. The
advantage of a snap flask is that any number of molds can
be made with one flask without requiring the flask for
Fig. 4. — Square snap flask.
pouring them. After the mold has been finished, the flask
is unsnapped and moved away from the completed mold.
Should there be any danger that the sand might burst
out due to the pressure of the metal when pouring, the
mold is protected with a bottomless box, called a slip
Fig. 5. — Round snap flask.
jacket. The slip jacket is slipped over the mold before
pouring.
Slip jackets may be made of either wood or metal.
FLASKS
23
Figure 6 shows a metal jacket. The number of jackets
required for one mokler depends on the number of his
molds that can be poured with one ladle of metal. Usually
a molder needs from three to ten jackets for a day's work.
Fig. 6.— Slip jacket.
After the metal has solidified the jackets are taken from
the poured molds and slipped over some that have not been
poured. This shifting process is continued until the day's
output of molds has been poured.
Fig. 7. — Wood flask for floor molding.
The type of wooden flasks used in floor molding is shown
in Fig. 7. Flasks larger than 18 in. square should have cross
rods varying in size from i/4 to 1 in. in diameter at the end.
Such rods are shown at A, Fig. 7. For some of the smaller
flasks, one rod at each end of the cope and one at each end
24
FOUNDRY WORK
of the drag are all that are necessary. Larger flasks must
have two or more rods at the ends and one or more in the
middle, especially when the cope is deep.
Large flasks should be equipped with trunnions or lift-
ing hooks, which serve as handles when lifting the flasks
Fig. 8.
A ~-B
-Trunnion and lifting hook.
A B
Fig. 9. — Flask pins and sockets.
by means of a crane. Figure 8 shows at A a trunnion and
at B a lifting hook.
In Fig. 9 are shown two styles of flask pins used on
wooden flasks. The open slot style A is used more than
the pin hole style B. There are advantages as well as dis-
advantages to either style.
Fig. 10. — Small pressed steel flask.
Small pressed steel flasks, similar to the one shown in
Fig. 10, are used instead of snap flasks for bench molding
in many technical school foundries. They are very service-
able and have been proved to be quite a success.
Table I gives flask sizes, thickness of lumber required
for different sizes, and the number of cross bars necessary
FLASKS
25
in each flask. The number of cross bars required is based
on the assumption that it is good practice to allow about
6 in. of sand between bars.
Table I. — Dimensions for Wooden Flasks
Flask sizes
in inches
Thickness
of sides
and ends
in inches
Depth of
cope and
• drag in
inches
Thickness
of cross
bars in
inches
Number
of cross
bars
required
per flask
From 10x10 to 16x16. .
1
2
2H
3
4 to 6
4 to 8
5 to 10
6 to 18
6 to 24
6 to 30
From 18x18 to 30x30. .
From 32x32 to 48x48..
From 50x50 to 60x60..
From 62x62 to 70x70 . .
From 72x72 to 84x84..
1
2
2 to 4
4 to 7
7 to 9
10 to 12
12 to 13
MOLDING AND BOTTOM BOARDS
There should be at least one smooth board for each size
of flask. This smooth board is called the molding board
Fig. 11. — Molding Board
and is used to rest the pattern and flask on when starting
to make the mold. A molding board should be as large as
the outside of the flask and stiff enough to hold up the sand
and pattern without springing when the sand is rammed.
Cleats of suitable size should be nailed to the under side
26
FOUNDRY WORK
of the molding board. Their purpose is to stiffen the board
and to raise it from the bench or floor (see Fig. 11) to allow
the molder to get his hand under it when rolling over the
mold. They also provide space for clamps when the mold
is clamped for rollover.
One bottom board is required for each mold, since the
sand must rest on a support until after the mold has been
poured. Bottom boards are similar to the molding board
shown in Fig. 11, but need not be finished so smoothly.
Table II gives the thickness of lumber required to make
bottom boards for different sizes of flasks.
Table II. — Lumber Required for Bottom Boards
Board sizes
in square inches
Thickness
of
boards
in inches
Thickness
of
cleats
in inches
Number of
cleats
to
board
From 10 to 16
^tol
1 to m
iMtoli^
11^ to 2
1^x1^
2x3
3x3
4x5
2
From 18 to 30
2
From 32 to 48
3
From 50 to 84
4 to 5
CLAMPS AND WEIGHTS
Almost all molds except those which have been made in
snap flasks must be clamped before they are poured, in
order to prevent the different parts of the mold from lifting
up and separating, due to the pressure of the metal. Snap-
flask molds are held together by weights during pouring.
Three types of clamps used commercially are shown in
Fig. 12. They are the Thompson clamp. A; Chaleau clamp
B; and an unnamed clamp, C, the most widely used. Those
shown at A and B are adjustable and can be made to fit
flasks of different sizes. All of the three types can be made
of gray cast iron, malleable iron or steel.
The number of clamps required on a mold depends upon
FLASKS
27
the pressure of the metal and the size of tlie mold. Fast
pouring gives more lifting pressure than is produced by
slow pouring. When a mold is poured with dull or cold
metal, there is likely to be more lifting pressure produced
than if the mold is poured with hot metal. This is due to
the fact that the molder naturally pours the cold metal
faster in order to run the casting before the metal solidifies.
Molds should always be clamped in such a manner that the
metal will not run out at the joints. When there is doubt
as to the number of clamps needed, it is a good rule to put
on an extra clamp or two rather than not enough.
/>■
ff^
^
Fig. 12.— Clamps.
Sometimes molds are weighted instead of being clamped.
When no other suitable weights are at hand, pig iron or
heavy pieces of scrap iron can be used. Almost all
foundries, however, make weights to suit their particular
kinds of work. Weights are usually made of gray iron,
and when they are made for snap flask use, they should
be from 1 to 2 in. thick and large enough to cover the
entire top surface of the cope. They should have slotted
holes in the center to permit the metal to be poured into
the mold, and openings at the ends to facilitate handling.
A style of weights commonly used for snap-flask molds is
illustrated in Fio;. 13.
28 FOUNDRY WORK
Computation of the weight needed to hold down a cope
is not often required. The following rule will be of -assist-
ance: Multiply the area of the surface of the metal which
presses against the cope by the height from the surface to
the top of the sprue, and the product by 0.26. (The factor
0.26 is the weight of one cubic inch of iron.) From the
second product subtract the weight of the cope. The result
will be the approximate weight that must be placed on top
of the mold.
To find the approximate weight of the cope after it has
been rammed, multiply the width of the cope in inches, by
Fig. 13. — Snap flask weight.
the length in inches, the result by the height in inches, and
that product by 0.06. (The factor 0.06 is the weight of one
cubic inch of rammed sand.)
Example. — Assume that a casting 12 in. wide, 18 in. long and
1 in. thick is to be molded in a wooden flask, 18 X 20 in., with a
cope 5 in. deep. How much weight should be put on the mold
to hold the cope down?
Solution.— 12 X 18 X 5 X 0.26 = 280.8 lb., which is the fluid
pressure acting to force up the cope. The weight of the cope is:
18 X 20 X 5 X 0.06 = 108 lb. The fluid pressure is 280.8 lb. and
deducting the weight of the cope (108 lb.) leaves 172.8 lb., the
weight that must be added.
CHAPTER VI
GATING MOLDS
There is always more or less dirt and scum floating on
top of and mixed with molten metal, and many castings
have to be scrapped because this dirt finds its way into the
molds. Some of the dirt can be skimmed off while the
metal is in the ladle. Even though the iron be skimmed,
there will be some dirt to deal with and it must be kept
out of the mold as much as possible by proper gating and
pouring.
The term gate, as applied in molding, is any opening
in the mold through which metal is poured to run the
castings. There are many styles of gates, but they can be
classified in two groups, common and special. The gate
with funnel-shaped top, the skimming gate, and pouring
basins compose the common group, while the horn and
whirl gates are called special. The kind of gate to be used
depends upon the size and shape of the casting and upon
whether or not the casting must be clean. Some castings
may be full of dirt holes and still not be disqualified for
use, while others have to be scrapped if they have a dirt
hole the size of a pin head.
Points to remember when gating a mold are: Cut the
gate a little deeper under the sprue than next to the pattern,
so that some of the metal will stay in the gate when pour-
ing. This metal acts as a cushion for the following metal
to fall on, and prevents cutting of the sand in the gate.
Gates should be cut just large enough to allow the metal
to run through at a speed that will not fail to run the
castings. They should not be so large that when the gate
is broken off it will break into the casting proper, nor so
29
30
FOUNDRY WORK
large that when the mold is poured the gate cannot be kept
full of metal. Dirt is not so apt to run into the castings
when the gates are kept filled as it is when they are kept
only partially filled. The reason is that the dirt, being
lighter than the metal, floats on top, allowing the clean
metal to run into the mold. This is one of the reasons why
castings gated from the bottom are cleaner than if gated
from the top. Thin castings should be gated with a wide
and shallow gate, which will allow the metal to run through
fast and will leave the gate weak so that it can be broken
off without breaking the casting.
Fig. 14. — Mold gated with common gate
There is always more or less danger that the metal will
cut the sand when pouring. It is a danger that can be
partially eliminated in three ways: First, by so placing the
gates that the metal will flow into the mold without running
against obstructions; second, by placing the gates where
the metal will not have too much fall w^hen entering the
mold; and third, by running the metal into deep places
where it will form a puddle for the rest of the metal to
run into.
The gate most extensively used for small and thin cast-
ings or for castings that need not be very clean, is shown in
Fig. 14, in which A is the sprue made with a funnel shape
at the top, B is the gate cut in the drag, and C is the
casting.
The gate shown in Fig. 15 is known as the skimming
GATING MOLDS
31
gate. It is used chiefly on castings that are to be as nearly
as possible free from dirt. The skimming gate is made by
setting the sprue, A, and the skimmer, B, in the cope and
connecting them by the channel, C, after the cope is lifted
off. The channel should be made a little larger than the
gate, D. The metal must be poured into the sprue fast
enough to force it to rise to the top of the skimmer and
the sprue and skimmer must be kept full throughout the
pouring. If not, the dirt that passes through the sprue will
not float to the top of the skimmer but will run into the
casting. Skimming gates require more metal than the one
1^^ m^mmmm:mm
Fig. 15. — Mold gated with skimming gate.
shown in Fig. 14 and therefore should be used only when
clean castings are to be made.
Pouring basins are used for running large castings. The
sprue may be set on top of the pattern or the castings may
be gated on the side. When the basins are made properly
they will collect and hold the dirt. Great care, skill and
good judgment must be exercised in building proper basins.
The size of the basin depends upon the size of the sprue and
the amount of metal required to fill the mold. It also
depends upon the time in which the mold must be filled.
Basins must always be made in such a manner that they
can be kept full of metal when pouring, because if they
are not kept full the dirt will flow into the casting and the
32
FOUNDRY WORK
result will be just as bad as though no basin had been used.
A mold gated with a pouring basin is illustrated in Fig. 16.
The basin is shown at A, the sprue at B, and the casting
at C. It will be noted that the basin is lower at D than
■ggn TFT
Fig. 16. — Mold gated with pouring basin.
at E. The metal should be poured into the basin slowly
at D until it begins to run over at E into the sprue, when
the basin should be filled as quickly as possible.
Many large castings must be gated from the bottom
because of the long fall the metal has to make to reach
Wl M"
Fig. 17. — Mold gated from the bottom.
the bottom of the mold. It is best to gate very deep molds
at the bottom and to run the metal to the bottom of the
mold by steps. Figure 17 shows a step gate suitable for
GATING MOLDS 33
large and deep castings, especially if the castings must be
made clean. One of the objections to bottom pouring is
that extra work is required to make the gates. However,
if the metal is run through a bottom gate core, as shown
at A, Fig. 17, the amount of extra work is very slight.
Sometimes it is desirable to fill the mold quickly, in which
case more than one gate core may be used. All jobbing
shops should carry bottom gate cores in stock. They are
easily made in halves, as shown at BB, Fig. 17, the halves
being pasted together after they are baked. They may be
made smaller by rubbing the halves together, or larger by
filing the runner, before pasting. A good size of core to
carry in stock is one that has a runner about 1 in. dia. The
core may be about 5 in. long, 3 in. wide and 3 in. thick.
Cores of this size will run any casting similar to a steam
engine piston weighing approximately 800 lb.
CHAPTER VII
SHRINKAGE
Iron contracts, or shrinks, as it passes from a liquid form
to a solid state. The shrinkage will be more noticeable in
large castings than in small ones, although of course the
coefficient of expansion (and therefore of contraction) is
a constant. More time is required for metal to solidify
in large bodies than in small amounts so that in a large
casting the mold will have been filled while the metal is
still molten. In small castings, the iron shrinks almost as
it is poured, providing opportunity at once to make up for
a part of the contraction. The metal in large castings will
stay in a fluid state for several hours and in such cases
much shrinkage trouble may be experienced.
Shrink holes are generally found in that part of a cast-
ing where the metal has solidified last. One may look for
shrink holes at or near the top of a casting, that is, in the
part that was uppermost when the mold was poured.
While nearly all metals shrink when they solidify, there
are scarcely two that shrink to the same extent. Aluminum
and steel shrink more than brass or gray iron, and not all
grades of gray iron have the same shrinkage. That being
the case, it is necessary for a molder to study the metals,
not forgetting to take into consideration the size of the
casting and the length of time that will be required for
the metal to solidify. The pouring temperature of the
metal, also, is a factor that must be watched, because
metal poured when hotter than necessary will cause more
shrinkage than it would have caused if poured at the
proper temperature.
There are two ways in which shrinkage may be counter-
acted. One method is to feed metal into the casting while
34
SHRINKAGE 35
it is solidifying. The other method is to chill the heavy
sections of the casting to cause them to solidify as cjuickly
as the lighter sections. If all parts of the casting solidify
at about the same time there is not much danger that shrink
holes will be produced, but if one part solidifies much before
some of the other parts there is great danger that shrink
holes will exist in the parts that harden last.
There is shown in Fig, 18 a dumb-bell casting with a
shrink hole in each ball. It will be noticed that the shrink
hole at B is on the inside of the casting, with a shell of
metal around the hole. This kind of shrink hole is common.
It exists because the metal becomes hard on the top sur-
face of the casting before it has solidified on the inside.
The shrink hole shown at C is even more common. The
Fig. 18. — Dumb-bell casting with shrink holes in each ball.
metal remained fluid on top until the inside became hard
and the metal that was at C was drawn into the casting.
When a casting of the type shown in Fig. 18 solidifies,
the handle A and the metal next to the damp sand becomes
hard first and while so doing draw metal from those parts of
the casting that are still fluid. If the parts drawn upon
cannot in turn draw metal from somewhere else, the shrink
holes are bound to exist. They can be prevented by feeding
metal into the balls as will be shown.
In Fig. 19 the method of feeding a dumb-bell casting is
shown. It is necessary to feed each ball separately, wiiich
is done by placing a feeder on each end as shown at B and
C. If the casting were fed in one ball only, the other might
contain a shrink hole, because the handle would probably
freeze and not allow the metal to feed through. The con-
36
FOUNDRY WORK
nections between feeders and balls, as shown at DD, must
be large enough that they will not freeze too quickly.
Holders who have had very little experience in feeding
castings often make the connections between the feeders
and casting so small that the metal in the feeders and
casting is still fluid after the connections are frozen. When
feeders contain shrink holes as shown at B and C, they
have generally done their duty and the castings are almost
certain to be free from shrink holes.
Feeders may be placed on top of the casting as shown
in Fig. 20. When so placed, the size of the feeder depends
upon the length of time necessary for the metal in the cast-
FiG. 19. — Dumb-bell casting with feeder attached.
ing to solidify. Many times feeders that are too small are
used and they cause more damage than they do good.
When a feeder, placed on top of a casting, solidifies before
the casting does, metal will be drawn from the casting by
the feeder instead of being fed into the casting from the
feeders. On the other hand, if the feeders used on large
castings are made large enough for the metal to remain in
a fluid state until the casting has solidified, they have to be
so large that their removal is very costly.
CHURNING
One of the greatest difficulties found in feeding castings
is to keep the metal in the feeder in a fluid state until the
castings are solid. This always has been a problem under-
stood by few molders, and those who do understand it are
those who have worked a great deal in jobbing shops or
SHRINKAGE
37
where large castings are made. Feeding large castings
successfully requires not only good judgment but also a
great deal of experience with large work.
The term churning as applied to foundry work refers
to a method of agitating the iron after a mold has been
poured. A wrought iron rod is pushed through the metal in
the feeder, down into the casting and is then moved up and
down continually being gradually withdrawn as the iron
y^lj;
■ /;
t,...,.v.,v...,.v.... ---••Ob»,£^/
'.-.■".'■■:'V;';/-1x-;.
Fig. 20. — Mold gated from the bottom with feeder placed on top.
solidifies. In Fig. 20, A represents the feeder, B the cast-
ing, and C the churning rod.
A rod 1/4 in. in diameter may be used for a feeder 3 in.
in diameter, A % in. rod would be suitable for a 4 in.
feeder. For a feeder 6 in. in diameter a feeding rod about
1/2 in. in diameter would work well. For feeders larger
than 6 in. in diameter still larger churning rods must be
used. Rods may be from 18 in. to 4 ft. long. The length
of rod to use depends upon the height of the feeder and
the depth of the casting to be churned.
38 FOUNDRY WORK
A churning rod should be heated before it is inserted
into the metal. If it is not heated, the metal surrounding
it will chill and stick to it making the operation of churn-
ing difficult.
To churn a casting properly, select two rods of the
required size. One rod is sufficient for some castings, but
it is well to have the second ready if the first becomes
unwieldy due to the weight and volume of the metal that
will adhere to it. Where there are two feeders on the cast-
ing, two rods are necessary of course. Heat the rods before
the mold is poured. After it is poured, watch the metal in
the feeder. When it begins to show signs of freezing, gently
push the hot churning rod through the feeder into the cast-
ing and carefully work it up and down. Do not strike the
sides of the feeder, push the rod to the bottom of the mold
or push it into a core. Continue to pour hot metal into the
feeder, whenever the feeder begins to show signs of freez-
ing, until the casting is solid. It is easy to tell by feeling
the resistance offered to the motion of the churning rod,
when solidification is taking place, and therefore, the time
when the rod must be withdrawn. After the rod has been
withdrawn, fill the hole in the feeder with hot metal.
BREAKING GATES AND FEEDERS FROM CASTINGS
Gates and feeders are generally broken from gray-iron
castings by striking the sprue or feeder a hard blow with a
hammer. When gates and feeders are small they break off
nearly even with the castings. When large there is danger
of breaking into the castings, especially if the feeder con-
nections are as large as shown in Fig. 19. There is also
more or less danger of breaking into the casting when the
feeder is placed on top as shown in Fig. 20.
When making a feeder connection a fillet should be
allowed next to the casting, as shown at EE in Fig. 19. The
weakest parts of the connections are shown by the dotted
SHRINKAGE 39
lines. The feeders should break on the dotted lines, leaving
about % in. of metal on the casting, which must be romoved
by chipping or grinding. This method requires a little
extra work, but this is amply repaid by the prevention of
scrap.
s, ^
v^
<
^O
■cX"*
cN
.«-" .^^
# ^^
i^
CHAPTER VIII
GAGGERS
Gaggers are generally used to support hanging bodies of
sand when making molds on the floor. They can be made
of cast or wrought iron and can be round or square. Figure
21 shows a type of gagger generally used. The toe A is
from 3 to 5 in. long, and the shank B may be made from
4 to 20 in. long, as required. In some shops cast-iron
gaggers have the preference, while in others the wrought-
iron gaggers are chosen.
-H
4"
I
31'
3
Fig. 21. — A gagger.
Almost all foundries make their own gaggers. They are
easily molded when made of cast iron, especially if the
patterns are fastened to a plate or board as shown in Fig.
22. It will be noticed that gaggers of various sizes may be
made at one time in one mold. When using the gagger
board, they can be made either in open sand or in a flask,
a matter that each foundry must decide for itself.
A handy gagger mold with two working-sides is shown in
Fig. 23. This mold is known as the Falls air-cooled mold.
It is made of cast iron and is hung on trunnions on a frame,
as shown at A. When used it must be set in a level position
for pouring. As soon as the metal is solid, the mold is
GAGGERS
41
turned over and the gaggers drop out. The. ft^gtcond side can
then be poured. The advantage of a mold liKethis is that
many gaggers can be made before the mold weafso.ut.
Fig. 22. — A gagger plate.
Some molders prefer to shake a little graphite or black
lead on the mold each time that they pour in metal. It is
a good plan, because it prevents the metal from sticking.
The mold should be free from rust when in use. If rust
is present the metal may blow out.
Fig. 23. — Falls air-cooled gagger mold.
SETTING CROSS-BARS AND GAGGERS
The sand on the inside of a pattern must be lifted out of
the pattern with the cope and it is supported by cross-bars
and gaggers. The bars are nailed to the sides of the cope
and should be from 5 to 6 in. apart. They should not be
more than I/2 to 1 in. from the pattern. Bars 1, 2, 3, 6 and
7, shown in Fig. 24, are placed in the flask properly, but
bars 4 and 5 are too far from the pattern. When bars are
far from the pattern, there is too much hanging sand under
them and it is likely to fall due to its own weight when the
cope is lifted.
42
FOUNDRY WORK
Good judgment must be used when setting gaggers. The
molder should always study the pattern and set the gag-
gers where the sand is apt to break when the cope is lifted.
The sand that is likely to fall when the mold is closed must
be supported by gaggers, nails or rods. In other words it
must be reinforced. There should not be more than i/4 in.
of sand between the gaggers and the pattern. The gaggers
should stand straight against the cross-bars, as shown in
Fig. 24. Those shown at B, F, I and J are set properly.
Those shown at C, D and H are not set properly; they
would interfere with the ramming of the sand. The gaggers
shown at A, E and G are too far from the pattern ; the sand
under them would be apt to stay down when the cope is
lifted or drop off when the mold is closed.
Fig. 24 —Proper and improper methods of setting gaggers.
Gaggers long enough to support the sand must always be
selected. They may stick out of the flask as shown at F,
bar 5, but it is better if they are even with the top of the
flask. The gagger shown at E would not support the sand,
because it is too short. As iron is about four and one-half
times as heavy as rammed sand, the gagger referred to
would only add extra weight to the sand instead of afford-
ing support.
CHAPLETS
Chaplets are metal supports that are used to hold dry-
sand cores in place when they are set and when the mold
is poured. The metal in the casting should burn on to the
chaplet and form a union with it. Otherwise the chaplet
GAGGERS
43
may be loose and a weak casting result. Or if the metal
in the casting and that in the chaplet are not well fused,
an air, water or steam test will probably show a leak
around the chaplet.
There are shown in Fig. 25 some of the many types of
chaplets extensively used. Those lettered A and B are
known as perforated chaplets, a style used for light and
thin castings. The cup chaplet, C, is used to a great extent
Fig. 25.— Chaplets.
in making small steam engine pistons. The double flanged
chaplet, D, the bridged chaplet, E, and the right angle
chaplet, G, are used in a great many varieties of castings.
The straight stem chaplet, F, is used when the pressure of
the metal is so great that the other types cannot be used.
Chaplets are generally made from sheet and wrought iron.
They are made from thin sheet iron known as tin in sizes
up to 2 in. thick. Many foundries make their own chap-
lets, others buy them from the foundry supply houses.
They should be kept in a dry place to prevent rusting.
44
FOUNDRY WORK
Coating them with tin, oil, red-lead or chalk will protect
them. A rusty or wet chaplet must never be set in a mold
as the metal will not lie against rust or dampness.
Care must be used in selecting the proper chaplets for
the job. They must be stiff enough to hold the core in
place, not only when it is set, but while it is under the
pressure of the metal during pouring. If the chaplets bend
at any time before the metal has solidified, the core will
float, because it is only one-fourth as heavy as cast iron.
Chaplets must not be so heavy or thick that the metal
around them will chill instead of fusing with them.
SETTING CHAPLETS
The shape of the casting, the shape of the core, the
thickness of the metal in the casting, and the pressure to
Fig. 26 — Core supported with chaplets.
which the core is subjected when pouring are factors that
must be considered when selecting and setting chaplets.
One of the ways in which a core may be supported in a
mold is shown in Fig. 26. The core, B, is held in place
and located by the two core prints, CC. The chaplets
AA, are placed on top of the core. These chaplets should
be of the same thickness as the metal on top of the core.
When the mold is closed the cope will fit down on the
chaplets and the core will be held in place assuming that
the chaplets do not melt before the metal has solidified
GAGGERS
45
and that the pressure under the core is not so great that it
will press the chaplets into the sand of the cope.
In Fig. 27 there is shown a core supported by straight
stem chaplets, and a method generally used in securing the
chaplets. The chaplet at F is driven into the bottom board,
which gives it a solid support. The chaplet G is driven
into a board embedded for that purpose in the sand when
the drag was rammed. Eitlier method may be used, but
driving the chaplet into the bottom board is the better and
should be followed when possible. In either case the chap-
FiG. 27. — Proper and improper methods used in setting chaplets.
let should project out of the sand a distance equal to the
thickness of the metal to be in the casting. The core, H,
is located by the core print, J, and is held up by the two
chaplets to which reference has been made.
The chaplets A, B, C, D and E, should project out of the
top of the cope about i/i in. when they are down on the
core, that is, after the mold is closed. They should be in a
vertical position and not slanting like the one shown at D,
which is incorrect because it does not offer as much resist-
ance to the pressure of the iron as do the vertical ones.
The chaplets on top of the core in the cope need blocking
46
FOUNDRY WORK
and wedging, which can be done in different ways. The
method shown in Fig. 27 is safe and is used a great deal
for small as well as large cores. The blocks shown at 3 3
are placed on top of the flask after it is closed. They are
about IV2 in. thick and as long as necessary to afford a
rest for the beam, 1. The beam should be made of either
iron or steel. Wood is not desirable because it will burn
readily and because it is not strong enough.
The beam should be placed across the mold and chaplets
with a space of about 1 in. between chaplets and beam.
A
-=~=:Sl^^~ -~- ' ~"^
1
^
...A.. 5" J
Fig. 28.— Wedges.
That amount of space is needed for blocking and wedging.
Before putting in the wedges the mold should be clamped
by clamps that reach from the bottom of the mold to the
top of the beam as shown at 2. Proper and improper
methods of blocking between the chaplets and the beam are
shown at A and B, and C, D, and E, respectively. The
methods shown at C, D and E, are likely to give, allowing
the core to float.
WEDGES
The wedges used for blocking on top of the chaplets
should be made of iron. Wooden wedges will burn, espe-
cially if a long time is required for the metal to solidify.
Any foundry can make its own wedges or they may be
GAGGERS 47
bought from foundry supply houses. They should be made
of either hard wood or iron.
The wooden wedge shown at A, Fig. 28, is used when
clamping molds for rolling over and for pouring. It is of
the proper shape, style and size. The iron w^edge, B, is of
the type used for wedging on top of chaplets.
CHAPTER IX
TOOLS
Many types of tools and appliances are used for making
molds. The kind of tools to select depends upon the shape
and size of the castings to be made. Only such tools as
are needed in this course will be taken up.
A line of tools commonly used by all molders is shown
in Fig. 29. The shovel, shown at A, is indispensable. It
should always be kept clean, not only to protect it from
wear but because a clean shovel can be handled more easily
and faster than a dirt}^ one. A rusty shovel or one coated
with sand is a very clumsy tool.
There are two types of rammers. The one shown at B
is used for making molds on the floor and is known as the
floor rammer. It is usually about 4 ft. long. The rammer
shown at C is used in making molds on the bench and is
known as the bench rammer. It is usually from 16 to 20
in. long. The wedge-shaped end of a rammer is called the
peen and the other end is called the butt. The terms peen
and butt are used for both floor and bench rammers.
The bellows, D, is a standard type, used for both bench
and floor molding.
The riddle, E, is used to sift sand that is put next to the
pattern. Riddles are numbered according to the size of
the openings between the wires. A No. 2 riddle has two
openings to the inch, a No. 10 has ten openings and so on.
The No. 4 and No. 6 are used more than the other sizes.
The brush, K, used by the majority of foundries, is one
of the standard types.
The swab, L, is used to moisten the sand around the
patterns before they are drawn. The one shown is made
of hemp. Sponges or waste can also be used for swabbing
around patterns.
48
TOOLS
49
Fig. 29.— Molding tools.
50
FOUNDRY WORK
The straightedge, F, is used to cut the sand level with
the flask, after the mold is rammed.
The wire, /, is called a vent wire. The object of vent-
ing, and the necessity for it, were explained in Chap. IV.
All patterns must be rapped before they are drawn from
the sand. The draw-spike, G, is driven into the pattern by
means of the rapping-bar, H. The wood screw, M, is also
used for drawing patterns. If the patternmaker has put
threaded draw holes into the pattern, which is often the
case, the draw-screw, J, should be used.
A molder should supply himself with a set of small tools.
It is common practice to see an apprentice select all kinds
Fig. 30.— Molders tools.
and sizes of tools, only to find later that he has many for
which he has no use. That is a mistake. It is better to
select a few tools and add to them when necessary. The
illustration. Fig. 30, shows a set of tools that will meet
nearly all of the requirements for bench or floor molding
in commercial foundries as well as in schools. However,
for special work, many other tools are needed.
The trowel, A, is known as the finishing trowel. The
one shown at B, is called the square trowel. These trowels
should be about V/^ in. wide and from 5 to 6 in. long.
The lifter, C, is used chiefly for floor work and usually
two lifters only will be necessary. One should be i/4 in. wide
TOOLS 51
and 10 in. long, the other % in. wide and from 14 to 18 in.
long.
The slick, D, is known as the double-end slick and
spoon. This slick should be about 1 in. wide for ordinary
work.
The tool, E, called a Yankee lifter is a combination of
slick and lifter. It is used in bench molding. A slick about
V4. to % in. wide is a good size.
The tools just described are used to make parting sur-
faces, slick down joints, repair any broken parts of the
mold and clean loose sand out of the mold.
The gate-cutter, F, is used to cut gates from the bottom
of the sprue hole to the pattern. It can be made from thin
sheet iron about 4 in. square, or from thin copper sheeting.
When the cutter is made, the iron or copper sheet should be
bent as shown in the illustration. Then when cutting gates,
it can be bent to suit any requirement.
QUESTIONS
1. Name the essential properties of a good molding sand.
2. How is the sand tempered for making molds?
3. If the sand is used too dry, what effect will it have when making
molds?
4. What is the effect on the casting if the sand is too wet?
5. When a mold is rammed too hard what will be the result?
6. What will be the result if the sand is rammed too soft?
7. What is a green-sand mold?
8. What is a skin-dried mold?
9. What is a dry-sand mold?
10. How do the steam and gases escape from the mold?
11. What is a green-sand core?
12. What is the difference between two- and three-part flasks?
Name the parts of each.
13. Of what materials are flasks made?
14. What are the advantages of using a snap flask?
15. What are slip jackets and snap -flask weights, and why are they
used?
16. Why should not the partings of a mold be slicked down after the
cope is lifted from the drag?
17. Name two possible causes of blow holes in a casting.
52 FOUNDRY WORK
18. Explain the different methods of facing molds, and name the
materials used in each case.
19. Make a sketch of a mold showing it gated with a common skim-
ming gate, and name the parts.
20. Make a sketch of a mold showing it gated with a pouring basin,
and name the parts.
21. Explain from a sketch the operation of a skimming gate.
22. Explain from a sketch the operation of a pouring basin.
23. Make a sketch of a mold gated from the bottom and made with
a feeder.
24. If the gates are too small what will be the result?
25. What are some of the causes of dirty castings?
26. Why are cross bars used in large flasks?
27. What materials are considered good materials for making
partings?
28. Why must heavy sections of castings be fed and how is the
feeding done?
29. What is meant by churning a casting?
30. What precautions must be used when removing large feeders
from castings?
31. What are gaggers?
32. When must gaggers be used?
33. Name some of the important things to be taken into consideration
when setting gaggers.
34. What are chaplets, and why are the}^ used?
35. Name some of the important things to be considered when select-
ing and setting chaplets.
36. Name at least five tools used in molding.
37. Is the molding sand used for heavy castings the same as that
used for hght castings? If not, why not? If so, why?
38. Why must flask pins fit?
39. How should gaggers be treated before setting them in a mold?
40. Is the same type of rammer used for floor molding as for bench
molding?
PART II
EXERCISES AND PROBLEMS
CHAPTER X
BENCH MOLDING AND MOLDING EXERCISES
Small castings can be made to a better advantage if the
molds are made on a bench, that is, if suitable flasks of the
proper sizes are used. Flasks 16 in. square, with the depth of
the cope and drag 5 in. each, are about as large as one man
can handle.
A flask of the proper size for the average college student
to handle is 14 in. square with the cope and drag each 5 in.
deep. For high school students a flask 12 in. square with
5 in. cope and drag is suitable.
The castings for which the bench molding exercises in this
course have been provided can be molded in flasks 14 in.
square with 5 in. cope and drag. The snap flask shown in
Chap. V, Fig. 4, or the steel flask shown in Chap. V, Fig. 10,
can be used.
Either a group of small patterns or one large pattern
can be used in the exercises. When a group of patterns is
put in a flask there should be 1 in. of sand between the
patterns. If the patterns are nearer together than 1 in.
there is danger that the sand will be too weak to stand the
pressure of the metal allowing the castings to run together.
There must be 1 in. of sand between the patterns and the
flask to prevent the metal from running out of the mold at
the joints. At least 1 in. of sand must separate the patterns
and the bottom board or the bottom board may burn when
the castings are cooling. The sand in the cope should be
at least 3 in. above the top of the pattern.
A wall type molding bench and tool arrangement are
shown in Fig. 31. They have been used with success for
school foundries. Figure 32 shows a typical portable mold-
55
56
FOUNDRY WORK
ing bench that can be used for school as well as for com-
mercial foundries.
Fig. 31. — Wall type molding bench and tool arrangement.
The exercises in the bench course take up the making of
molds in two- and three-part flasks, with and without the
use of dry sand cores. The rolling methods of making
Fig. 32. — Portable molding bench.
molds as well as the method of bedding the patterns in the
sand will be studied. Two of the exercises show how cast-
ings can be made that will differ from the pattern used.
EXERCISE 1. MOLDING TWO FACE PLATES
When studying the patterns for this exercise it will be seen that the
draft runs in one direction, from A to B and from C to D, as shown in
Fig. 33. The parting line is at ^4.
Fig. 33. — Face plate pattern.
Procedure in Molding
Place the patterns and drag on the molding board, with the pins on
the drag down as showTi in Fig. 34. Riddle molding sand over the
patterns to cover them to a depth of about 1 in., using a No. 6 riddle.
Fig. 34. — Pattern and drag placed on molding board.
Press the sand around the edges of the patterns against the molding
board with the fingers. Shovel the drag heaping full of molding sand
as shown in Fig. 35. Peen-ram around the sides of the flask first and
then in between the patterns.
I
1^^
Fig. 35. — Drag filled heaping full of molding sand.
Again fill the drag heaping full and butt-ram it nearly even with the
edge of the drag. With the straightedge strike off any sand that may
be above the edges of the drag. Punch vent holes with a wire 1/16 in.
in diameter, about 1 in. apart and reaching from the bottom of the
drag (now uppermost) to within Y^ in. of the patterns, as shown at
57
58
FOUNDRY WORK
A in Fig. 36. Throw sand, free from lumps, over the drag to a depth of
about }4, in. Rul) the bottom board on the sand until it lies on the drag
without rocking. Figure 36 shows the drag ready to be rolled over.
Grasp the molding and bottom boards at the ends with both hands
holding the drag firmly between the two boards and roll the whole over
Fig. 36. — Face plate drag rammed.
on the molding bench. Take off the molding board. SUck down the
sand with the trowel, to make a sohd parting. With the bellows, blow
all loose sand from the drag. Sprinkle parting sand on the surface
Fig. 37. — Face plate drag ready for the cope.
of the sand in the drag. Blow all parting sand from the patterns.
Figure 37 shows the drag ready for the cope.
Place the cope on the drag and see that the pins fit into the sockets.
Set the sprue pin half way between the patterns as shown in Fig. 38.
Jl jJlillL
^r^ —
tr:
.iliUi
^r
Fig. 38. — Cope and sprue set in making face plate mold.
Sift sand to a depth of 1 in. over the patterns. Fill the cope heaping
full of unsifted sand. Ram the cope just as the drag was rammed.
Strike off the sand even with the top of the cope. Vent the cope as
was done with the drag. Remove the sprue pin and cut the sprue hole
to a funnel shape at the top. Pack all loose sand around the sprue
BENCH MOLDING AND EXERCISES
59
hole with the fingers before lifting the cope. Figure 39 shows the mold
rammed, ready for the cope to be lifted.
Lift the cope and place it on the molding board, with the impression
taken from the drag, uppermost. The drag, after the cope has been
^
f
Ml m .
Fig. 39. — Face plate mold rammed ready to lift the cope.
lifted, is shown by Fig. 40. The cope, properly placed, is shown in
Fig. 41. Blow off any loose sand that may be on the mold. Swab the
sand next to the patterns with water, being careful not to get it too wet.
(Blow holes in the castings may result from wet sand.)
Lp^^
ZTT^
t^H: - ^
/ V//////^ ]|
y. .. .<,
1 ul
if
Fig. 40. — Shows drag of face plate mold after cope has been lifted off.
Drive the draw spike into each pattern in turn rapping on all sides
of the spike to loosen the patterns. Draw the patterns from the sand
carefully so as not to break the sand. If the sand does break the
broken places must be repaired and all loose sand in the mold must
^.zTv-,- "-: ^*-^^
^^T
^1
Fig. 41. — Shows cope of the face plate mold lifted from the drag.
be cleaned out, using either the lifter or the slick. If the tools are
dipped in water the sand will stick to them better than if they are used
dry. With the gate cutter, cut the gates in the drag, deepening slightly
60
FOUNDRY WORK
that part into which the metal will enter from the sprue. The gates
should be about 3^ in. deep and 3^ in. wide.
After the mold is patched and all the loose sand has been cleaned out,
close the mold by placing the cope on the drag with the pins in the
Fig. 42. — Face plate mold closed.
sockets as shown in Fig. 42. The mold must then be clamped together
as shown in Fig. 43, or a suitable weight must be placed on it. (See
Fig. 43. — Face plate mold clamped.
Chap. V.) The castings as taken from the mold, with the gates and
sprue attached, are shown in Fig. 44. A casting of the size made in
Fig. 44. — Casting with sprue attached.
this exercise should remain in the mold about 20 min. before the mold
is broken up.
EXERCISE 2. MOLDING TWO HEXAGONAL NUTS
The pattern of a hexagonal nut is shown in Fig, 45. It is made in
such a manner that it forms its own core which remains in the drag
when the pattern is drawn. The draft is in one direction, from A to B.
The procedure in molding is similar to that used in the first exercise,
but there are some differences.
\ r
T
Fig. 45. — Hexagonal nut pattern.
Procedure in Molding
Place the drag and patterns on the molding board with the pins
down as shown in Fig. 46. Riddle molding sand over the pattern.
Fig. 46. — Pattern and drag placed on molding board.
Press the sand into the inside of the pattern with the fingers to insure a
core that will not be too soft. Fill the drag heaping full of molding
i
^
li_LL
YT
t
Fig. 47. — Cope and sprue set when making hexagonal nut mold.
sand and ram as in Exercise 2. Strike off the excess sand, vent, place
the bottom board and roll the drag over. Take ofif the molding board.
61
62
FOUNDRY WORK
Before making the parting, press the sand that is to form the core and
if it sinks down as shown at C, in Fig. 47, fill the depression with molding
sand, even with the top of the pattern as shown at D. Make the
parting and sprinkle parting sand on the drag.
Set the sprue pin between the patterns and ram the cope. Level
the sand even with the top of the flask, vent, remove the sprue pin,
^ m
[r^-^J
Fig. 48. — Hexagonal nut mold closed.
and cut the sprue hole to a funnel shape. Lift the cope and place it
on the molding board with the face up. Blow all loose sand from the
drag and swab around the pattern being particularly careful not to
dampen the green sand core too much. With the vent wire, punch a
hole through the core as shown at ^ in Fig. 48, from the top down to
the bottom board. Rap and draw the patterns. Cut the gates, as
in the first exercise. Close the mold and clamp. It is now ready for
pouring.
EXERCISE 3. MOLDING A BALL HANDLE
The pattern used in this exercise is shown in Fig. 49. The parting
hne is at yl, the draft running in opposite directions. When the draft
runs in opposite directions it is good practice to have the parting Hne
even with the joint of the flask. This may be done by placing two
strips of wood half the thickness of the pattern, between the drag and
the molding board.
Fig. 49. — Ball-handle pattern.
Procedure in Molding
This exercise should be begun by placing the pattern and drag on
the molding board with the two strips of wood under the drag as shown
A "^D mi
Fig. 50. — Pattern and drag placed on molding board.
at A A, Fig. 50. The drag is then rammed as in the preceding exorcises.
After the drag is rolled over, remove the strips and molding board from
Fig. 51'; — Drag rolled over and parting made.
the drag. Make the parting by cutting away the sand from the edges
of the flask to the parting line of the pattern. One-half of the pattern
will then be above the drag as shown in Fig. 5L Set the sprue and cope
as shown in Fig. 52. Ram and vent the cope. Lift the cope and
63
64
FOUNDRY WORK
place it on the molding board. Blow all loose sand from the drag.
Swab, rap and draw the pattern. Cut the gate as shown in Fig. 53.
Fig. 52. — Cope and sprue set to make ball handle mold.
i
r~\.
V^
U'
'Hf
M^
Fig. 53. — Mold closed.
If the mold in the cope is broken, repair it by replacing the pattern in
its impression and patching around it. Close and clamp the mold.
EXERCISE 4. MOLDING AN OIL DRIP CUP
The pattern of the drip cup, shown in Fig. 54, has its parting hne at A.
The mold can be made with the pattern in either the cope or drag.
When made with the pattern in the drag, the sand on the inside of the
pattern has to be lifted with the cope, an operation that is troublesome
on account of the tendency of the sand to stick in the pattern. A
Fig. 54. — Drip cup pattern.
better method is to place the pattern on the molding board and ram the
cope first. Then the sand on the inside of the pattern will be in the
drag and will not have to be lifted out. This method is followed here.
Fig. 55. — Pattern, sprue and cope placed on molding board.
Procedure in Molding
Place the pattern, cope and sprue on the molding board as shown
in Fig. 55. Sift sand over the pattern. Fill the cope with sand and
Fig. 56. — Drag placed on top of cope.
ram as in the preceding exercises. Vent, draw the sprue pin, and roll
the cope over. Make the parting and sprinkle parting sand over the
65
66
FOUNDRY WORK
cope,
out.
The parting sand that falls into the pattern must be blown
Place the drag on the cope as shown in Fig. 56. The sand must be
kept out of the sprue hole when ramming the drag. To do so, press
a handful of molding sand into a ball about 3 in. in diameter, break
Fig
Mold. ready to roll over.
the ball into halves, and place one-half over the sprue hole. Sift sand
over the pattern and ram the drag as in the preceding exercises. Vent
the drag and roll the mold over. Figure 57 shows the mold ready to
be rolled over.
Fig. 58. — Mold ready to pour.
Lift the cope and place it on the molding board. Blow all loose sand
from the mold. Swab, rap and draw the pattern. Cut the gate, which
should be about 1}4 in. wide and 3^ in. deep. Clean all loose sand
out of the mold. Figure 58 shows the mold closed, ready for pouring.
EXERCISE 5. MOLDING FROM A SPLIT PATTERN
The pattern used in this exercise, shown in Fig. 59, is spht on the
parting hne. The parts are held together by means of dowel pins on
one side and dowel-pin holes on the other. There is to be an opening
through the casting made by a dry-sand core. Dry-sand coremaking
@
Fig. 59.— Split pattern.
will be taken up later. The pattern has two projections, A and B,
called core prints, used to locate the core and to hold it in place.
Place the drag and the half of the pattern containing the dowel-pin
holes on the molding board as shown in Fig. 60. Ram the drag, roll
Fig.
-Pattern and drag placed on molding board.
it over and make the parting. Place the cope half of the pattern on
the drag half with the dowel pins in the dowel-pin holes. Sprinkle
parting sand on the drag after the cope patterns are in place. Set
Fig. 61. — Cope, sprue and pattern placed on drag.
the cope and sprue as shown in Fig. 61 Ram the cope, vent it, and
draw the sprue pin. Lift the cope and place it on the molding board.
Blow all loose sand from the mold. Swab, rap and draw the pattern
from the cope and drag. Cut the gate and set the dry-sand core.
67
68
FOUNDRY WORK
The gas, which is freed in the core, can be let out of the mold through
holes punched into the cope sand as shown at ^^, Fig. 62. The gas
i
c
T^
i \
t-
:
bg^l"^'
Fig. 62.— Mold closed.
will pass through the hole in the core and out of the holes in the cope.
Close the mold and clamp it. Figure 62 shows the mold closed.
EXERCISE 6. MOLDING A PULLEY
The pattern, shown in Fig. 63, is spht on the parting Une, A A.
Fig. 63.— Pulley pattern.
Procedure in Molding
Place one half of the pattern and the drag on the molding board as
shown in Fig. 64. Sift sand over the pattern and ram the drag. Roll
the drag over and make the parting. Place the cope half of the pat-
FlG.
64. — Pattern and drag placed on molding board.
tern on the drag half. Set the cope and sprue pin. as shown in Fig. 65.
Ram the cope, lift it, and place it on the molding board. Swab and
rap the pattern in the cope and drag. Draw the pattern and cut the
gate. Set the core and make a vent channel through the cope, for the
Fig. 65. — Cope, pattern and sprue placed on drag.
escape of the core gas, as shown at A, Fig. 66. Close the mold, as
shown in Fig. 66, and clamp it.
Note. — The sand on the inside of the pattern in the cope may have
to be reinforced, especially if the molding sand is a little weak, so that
it will not drop when the mold is closed. Nails, about 1 in. longer
69
70
FOUNDRY WORK
than the width of the half-rim, should be used for this purpose. They
must be pushed into the sand before the pattern is rapped, until the
;i
■.^::};
iHii
4y
:;^,
1^^
':::_:■,
•■-•■-I/
•-it^ 1 ■
Fig. 66. — Mold closed.
heads are even with the sand. One nail between each two arms
usually is sufficient for a small pulley although more may be used.
EXERCISE 7. MOLDING A GOVERNOR PULLEY
Tho pattern, shown in Fig. 67, is in two parts, spl't at A A. It has
two parting Hnes, one at B and one at C. The draft runs from B to
A and from C to .4. While the mold must be made in three parts, it
Fig. 67. — Governor pulley pattern.
can be made in either a two- or three-part flask. The three-part
flask wall be used in this exercise. The core prints D should be attached
to the pattern by dowel pins.
Fig. 68. — Pattern and cheek placed on molding board.
Procedure in Molding
Place the pattern and cheek on the molding board as shown in Fig.
68. Ram the cheek, make the parting, and sprinkle on the parting
Fig. 69. — Cope and sprue placed on cheek,
sand. Place the cope and sprue as shown in Fig. 69. Ram and vent
the cope and draw the sprue pin. Place a bottom board over the
71
72
FOUNDRY WORK
cope and roll over the cope and cheek. Remove the molding board,
make the parting, and sprinkle on the parting sand.
Fig. 70. — Drag placed on cheek.
Fig. 71. — Mold ready to roll over.
f^J '"" E^_J
Fig. 72.— Mold closed.
Place the drag and core print as shown in Fig. 70. Ram and vent
the drag, lift it, and place it on the bottom board. Swab, rap, and
BENCH MOLDING AND EXERCISES 73
draw the drag half of the pattern. Rap the cope half of the pattern.
Place the drag back on the cheek. Sprinkle molding sand which is
free from large lumps over the drag and rub the bottom board down.
Roll the mold over. Figure 71 shows the mold ready to roll over.
Lift the cope and place it on the molding board. Swab and draw the
pattern from the cheek. Make the vent hole, A, for the escape of
core gas. Set the core. Close and clamp the mold, as shown in
Fig. 72.
EXERCISE 8. MOLDING A SHEAVE WHEEL
The pattern, Fig. 73, is split at A A. The parting hnes are at B
and C. The mold must be made in three parts, cope, drag and cheek,
using either a two- or a three-part flask. In this exercise it will be
shown molded in a two-part flask, with a false cheek, so named be-
cause it cannot be seen after the mold is closed.
Fig. 73. — Sheave wheel pattern.
Procedure in Molding
Place one half of the pattern and the cope on the molding board.
Set the sprue pin as shown in Fig. 74 and sift sand over the pattern.
Fill the cope heaping full of sand, ram, vent, and draw the sprue pin.
Fig. 74. — Pattern, cope and sprue placed on molding board.
Place a bottom board over the cope and roll it over. Make the part-
ing as shown in Fig. 75, sprinkle on the parting sand, and place the
drag half of the pattern. Sift molding sand onto the cope, tucking it
Fig. 75. — Parting made.
firmly into the sheave part of the pattern as shown at AA, Fig. 76.
Make the parting from the flange, CC, to the cope, Fig. 76. Sprinkle
parting sand over the cheek (on the parting and the cope but not on
the sand above the pattern). Ram the drag, lift it, and place it on
74
BENCH MOLDING AND EXERCISES
75
the molding board. Swab, rap and draw the drag lialf of the pattern.
Rap the cope half of the pattern. Place the drag back on the cope.
Fig. 76. — Cheek and drag rammed.
Roll over the mold. Lift the cope and place it on the molding board.
Swab and draw the cope half of the pattern. Make the vent-hole for
Fig. 77. — Mold closed
the escape of core gas as shown at A, Fig. 77. Set the core. Close
and clamp the mold, as shown in Fig. 77.
EXERCISE 9. MOLDING A BEVEL-GEAR BLANK
The pattern, Fig. 78, is in one piece with the parting hne at ^^.
A two-part flask is used and the pattern is arranged so that the parting
Hne is even with the joint of the flask. To do that it is necessary to
Fig. 78. — Bevel gear blank pattern.
ram a false cope and then embed the pattern to the parting hne as
shown in Fig. 79.
Fig. 79. — Pattern imbedded in false cope.
Procedure in Molding
After the pattern is arranged in the cope, place the drag and sift
sand over the pattern. Fill the drag heaping full of sand and ram.
Roll the mold over, lift the cope and shake the sand from it.
1^^^
Fig. 80. — Cope and sprue set on drag.
Make the parting and place the cope and sprue as shown in Fig. 80.
Ram and vent the cope, remove the sprue and lift the cope. Swab,
rap, and draw the pattern. Make the vent hole for the core gas and
set the core. Close and clamp the mold.
76
EXERCISE 10. MOLDING TWO FACE PLATES BY
EMBEDDING PATTERNS
In the exercise, the patterns will be embedded in the drag instead of
rolling the drag over, a method used under some conditions, frequently-
resulting in the saving of time.
Procedure in Molding
Place the drag with the pins up on the molding board as shown in
Fig. 81. Shovel it level full of unsifted sand. Peen-ram the sand
Fig. 81. — Bottom board and drag placed in place for bedding in face plate.
around the flask. Sift sand over the drag and strike it off level with
the top. Place the patterns on the sand and press them down even
with the top of the drag. With the fingers tuck the sand firmly under
the pattern. Peen-ram the sand around the pattern until it is even
"Ji:^^-i-^^r-
Fhj. 82. — Cope and sprue set.
with the top of the pattern and the drag. Make the parting and
sprinkle on the parting sand. Set the sprue and cope as shown in
Fig. 82. Ram the cope and finish the mold as in the preceding
exercises.
77
EXERCISE 11. THINNING A PLATE
The pattern is a plate 10 in. square and 1 in. thick. The casting
to be made is to be only 3^ in. thick. It is necessary to use two strips
of wood 3^ in. square and as long as the flask.
Procedure in Molding
Place the pattern and drag on the molding board with the pins
down. Lay the two strips of wood, AA, between the molding board
Fig. 83. — Drag and pattern placed on molding board.
and the drag as shown in Fig. 83. Sift sand over the pattern and ram
the drag. Roll the drag over, remove the molding board and make
the parting. Set the sprue pin and the cope, allowing the strips of
wood to remain on the drag and the cope to rest on them as shown in
Fig. 84. Make the cope as in the preceding exercises.
Fig. 84. — Cope and sprue set on drag.
After the cope is lifted, remove the strips of wood, and cut down
the sand around the pattern level with the top of the drag as shown in
Fig. 85. Swab, rap and draw the pattern. Cut the gate. Before
closing the mold, put some parting sand or wheat flour on the drag
near the edge of the flask to insure a tight point.
After the mold is closed the cope should be lifted again to observe
whether or not the sand in the cope touched the sand in the drag at
all points. If there are spots on the cope not marked by the flour,
78
BENCH MOLDING AND EXERCISES
79
more sand should be added to the drag, and the process repeated until
the bearing is complete.
Fig. 85.— Mold closed.
To prevent the metal from running out between the cope and drag,
which is likely to happen with this type of mold, tuck wet sand or damp
clay into the joint, after the mold is closed, but just before it is clamped.
EXERCISE 12. MOLDING A PULLEY LONGER THAN
THE PATTERN
The pattern is the one used in Exercise 6. The rim and the hub of
the casting are to be 3^ in. longer than the pattern. It is necessary
Fig. 86. — Pattern and drag placed on molding board. }(
to have two wooden strips 3^ in. square and as long as the diameter
of the pattern.
Fig. 87. — Pattern, cope and sprue set on drag.
Procedure in Molding
Place the pattern and the drag on the molding board, with the two
strips of wood, A A, under the pattern as shown in Fig. 86. Make
Fig. 88.— Mold closed.
the drag as in the preceding exercises. After the drag is rolled over,
take the strips of wood from the pattern. The pattern must now be
80
BENCH MOLDING AND EXERCISES 81
brought up level with the top of the drag. To hold the pattern up,
turn it so that the arms of the pattern rest on the sand which was
between them. Build up sifted sand around the pattern. Tuck the
sand around the pattern and under the arms with the fingers. The
sand must not be tucked too hard or it will be pushed under the pat-
tern. When the pattern is drawn up level with the top of the drag
and the sand is packed sohdly around it, make the parting. Set the
cope half of the pattern on the drag half. Sprinkle parting sand on
the drag and set the sprue pin and cope as shown in Fig. 87. The cope
is to be made as in Exercise 6. Figure 88 shows the mold closed with
the dry-sand core set in place.
CHAPTER XI
FLOOR MOLDING EXERCISES
The term floor molding" indicates that the molds are to
be made on the foundry floor instead of on the bench. The
tools used in bench molding can be used in floor molding
with the exception of the rammer. The rammer at B
shown in Fig. 29, should be used.
82
EXERCISE 13. MOLDING A CONE PULLEY
The pattern, Fig. 89, is 14 in. in dia. and 7 in. long with the parting
line at A. The flask should be 16 in. square with the drag 9 in. and
the cope 5 in. deep.
Fig. 89. — Cone pulley pattern.
Procedure in Molding
Place the pattern and drag on the molding board as shown in Fig. 90.
Sift sand over the pattern. Fill the drag about half full of sand and
peen-ram this layer. Fill the drag heaping full and peen-ram again.
This time ram the sand level with the top of the drag. Vent the drag
and sprinkle sand free from large lumps over the drag, about }4 in.
deep. Rub the bottom board on the drag, seeing that it lies firmly
Fig. 90. — Cone pulley drag rammed.
without rocking. Put two clamps on the drag before rolling it over
as shown in Fig. 91. Remove the clamps and molding board from the
drag and make the parting. Sprinkle on the parting sand and place
the cope and sprue as shown in Fig. 92. Sift sand over the pattern
and tuck it under the bars with the fingers. Peen-ram between the
bars, then fill the cope heaping full and butt-ram the sand level with
the to of the cope. Vent the cope and take out the sprue pin. Lift
the cope and set it on a wooden box or a pair of trestles as shown in
83
84
"I
FOUNDRY WORK
feD — ^^"^ — "-* ^^
Fig. 91. — Cone pulley drag ready to roll over
FiQ. 92. — Cope and sprue set.
Fig. 93. — Cope placed on trestle.
FLOOR MOLDING EXERCISES
85
Fig. 93. Blow all loose sand from the mold. Swab, rap and draw
the pattern. Cut the gate and set the core as shown in Fig. 94. Make
jmmww
mm^mm~j^
-mr- MJ
Fig. 94. — Core set in drag.
Fig. 95. — Mold closed.
the vent hole through the eope for the escape of core gas. Close the
mold as shown in Fig. 95 and clamp it.
EXERCISE 14. MOLDING A GAS ENGINE FLYWHEEL
If the weight of the casting is more than 50 lb., a sea-coal facing
composed of one part sea coal and ten parts sand should be put next
to the pattern. To feed the casting evenly, use two feeders as shown
in Fig. 97. Gate the casting on the hub.
Procedure in Molding
Place the pattern and drag on the molding board as shown in Fig,
96. Sift the facing over the pattern to a depth of about 1 in., then
Fig. 96. — Drag and pattern placed on molding board.
fill the drag level with the unsifted heap sand. Peen-ram between the
pattern and flask, but not over the pattern. Fill the drag heaping
full and step the sand down with the feet, then butt-ram firmly be-
tween the pattern and flask and ram lightly over the pattern. Heavy
ramming over the pattern may cause the casting to be scabbed.
Strike the sand off level with the drag, vent carefully, and sprinkle
on sand free from large lumps. Rub the bottom board down, clamp,
rtllrf
■^ m^T
Fig. 97. — Mold rammed up.
and roll the drag over. Remove clamps and molding board. Make
the parting, sprinkle on the parting sand and blow all parting sand
from the pattern. Sift molding sand over the drag about }4 in. deep.
Clean the molding sand from the flask joint and wet the inside of the
cope with a thin clay wash.
Set the cope, sprue, feeders and gaggcrs as shown in Fig. 97. Sift
sand over the pattern and tuck it firmly under the bars with the
86
FLOOR MOLDING EXERCISES
87
fingers. Fill the cope level full of sand. First, peen ram between the
bars, being careful not to strike the gaggers, then fill the cope heaping
full and butt-ram between the bars. Do not strike the tops of the bars.
Vent, cut the pouring basin as shown at D, Fig. 98, and draw the
sprue and feeders.
Fig. 98.— Mold closed.
Lift the cope and set it on a pair of trestles or a box. Blow all
loose sand from the mold. Swab, rap and draw the pattern. Cut the
feeder connections as shown at CC in Fig. 98. Put graphite facing on
the mold with a camel's hair brush or rub it on with the hand. Set
the core in the drag and make the vent channel for the core gas to
escape through the drag, as shown at E, Fig. 98. Close and clamp
the mold.
EXERCISE 15. MOLDING A SUGAR KETTLE
The patterns for the ears must be loose and must be spHt at BB, as
shown in Fig. 99. The mold can be made in more than one way, and
the casting can be run either from the sides or top. The best way to
mold from a pattern of this type is to use a green sand core in the drag,
because it insures that the inside of the casting will be clean. By
casting the kettle upside down the dirt will flow to the bottom of the
kettle (the top of the casting) where it will do no harm unless present
in an unusual amount.
Procedure in Molding
Place the pattern and cope on the molding board as shown in Fig. 99,
with sifted sand next to the pattern. With the fingers tuck the sand
Fig. 99. — Pattern and cope placed on molding board.
firmly around the ears A A. Fill the cope with sand to a depth of 5
in. Peen-ram between pattern and flask, being careful not to ram
-Drag set on cope.
the ears out of place. Cover the pattern with sifted sand and set a
flat sprue on top of the pattern. Fill the cope level full and peen-
ram, then fill the cope heaping full and butt ram. Vent and remove
8S
FLOOR MOLDING EXERCISES
89
the sprue pin. Sprinkle a bed of sand over the cope, place a board on
it, and clamp. Roll the cope over, remove the clamps and molding
board. Make the parting, clean all loose sand out of the pattern,
sprinkle on parting sand and rap the pattern. Place the drag as shown
in Fig. 100. Fill the inside of the pattern with sifted sand and ram it
lightly until it is even with the top of the pattern. Vent the sand on
the inside of the pattern. Fill the drag full and peen-ram, then fill it
Fig. 101.— Mold closed.
heaping full and butt-ram. Strike the sand off level with the top of
the drag and vent it. Sprinkle sand free from large lumps over the
the drag and rub down the bottom board. Clamp and roll the mold
over. Remove the clamps and board from the cope. Lift the cope
and place it on a pair of trestles. Blow all loose sand from the mold.
Swab, rap and draw the kettle pattern; then draw the patterns for the
ears. Face the mold with graphite. Close and clamp the mold.
Figure 101 shows the mold closed.
EXERCISE 16. MOLDING A STEAM ENGINE PISTON
When a casting of this nature weighs more than 50 lb., a sea-coal
facing, composed of one part sea coal to ten parts sand should be used
next to the pattern. Because the casting must be clean and sound, a
skimming gate and feeder should be used.
Procedure in Molding
Place the pattern and drag on the molding board as shown in Fig. 102.
Cover the pattern with facing and follow it with a layer of sifted facmg
Fig. 102. — Pattern and drag placed on molding board.
sand. Fill the drag level full with unsifted heap sand. Peen-ram
between the pattern and flask. Fill the drag heaping full and butt-ram
firmly around the pattern, but lightly over the pattern. Strike the
sand off level with the drag. Place the bottom board on the drag and
clamp. Roll the drag over and remove the clamps and molding board.
Make the parting and sprinkle on the parting sand.
W^TT^^J
i:^^r
Fig. 103. — Cope, sprue and feeder set.
Set the sprue, skimmer, feeder and cope as shown in Fig. 103. Sift
facing sand onto the cope and tuck the sand firmly under the bars.
Then fill the cope h^vel full and peen-ram between the bars. After the
cope has been peen-rammed, fill it heaping full between the bars and
butt-ram even with the tops of the bars. Vent, and draw the sprue,
90
FLOOR MOLDING EXERCISES
91
skimmer and feeder. Lift the cope and set it on a pair of trestles or a
box.
Swab, rap, and draw the pattern. Cut the gate and connect the
feeders in the drag. Rub graphite facing on the mold either with the
hand or a camel's hair brush. Cut the drag chaplets, A A, Fig. 104,
allowing >^ in. to be driven into the bottom board, and point them on
J
TZ
\:J
^ t^- I
R
Fig. 104. — Core set in drag.
the grinding wheel. Cut the cope chaplets, B, B, Fig. 105, long enough
so that when they are down on the core, with the mold closed, they will
stick out of the cope 14 in. Place the chaplets in the drag and set
the core as shown in Fig. 104. Push the chaplets through the cope and
press the sand on the top of the cope firmly around them.
Fig. 105.— Mold closed.
Place the cope on the drag to take an impression of the core prints.
Lift the cope again to see that it was bearing on the core prints. (A
little wheat flour or paste put on the print will often make a tight joint
over the core.) Punch the vent hole fore the dry sand core after the
cope has been lifted and make certain that the vent hole through the
cope is connected with the hole in the core. Close and clamp the mold.
Secure the chaplets in the cope as shown in Fig. 105.
EXERCISE 17. MOLDING A LATHE BED
The weight of the casting is about 75 lb. The parting hnes are at
A and B, and the pattern is spht at C, as shown in Fig. 106. The
mold can be made in either a three or a two part flask. In this exercise
a three-part flask wiH be used, and the casting will be gated from the
bottom.
Fig. 106. — Lathe bed pattern.
Procedure in Molding
Place the pattern and drag on the molding board as shown in Fig. 107.
Lay two strips of wood, A A, between the molding board and the drag,
to raise the drag even with the parting line of the pattern. Cover the
Fig. 107. — Pattern and drag placed on molding board.
pattern with sifted sand, then fill the drag heaping full of unsifted sand
and peen-ram. Again fill the drag heaping full and butt-ram. Strike
off the sand level with the drag and vent. Sprinkle on sand, rub
down the bottom board, clamp and roll over. Remove the clamps,
^^W^^ '^^^i^;^:-!^^^ ' j'^^i I'/' C v. ■-. s'-'^^ ' ^ ■- •^ i^:^7^:n5|lg^S-'-:^
Fig. 108. — Cheek and spnie set on drag.
molding board and strips. Make the parting and sprinkle on the parting
sand.
Set the cheek, sprue and pattern as shown in Fig. 108. Put sifted
sand next to the pattern and fill the cheek level full of unsifted sand.
92
FLOOR MOLDING EXERCISES
93
Peen-ram the cheek, then fill it heaping full and butt-ram. Make the
parting and apply parting sand. Clay wash the cope and set it on the
cheek. Set the riser as shown in Fig. 109. Sift sand into the cope and
tuck it firmly under the bars. Fill the cope level full with unsifted
sand and peen-ram between the bars, then fill the cope heaping full
Fig. 109. — Cope placed on drag and cheek
and butt-ram. Strike off the sand level with the top of the cope and
vent. Draw the sprue pin and feeder. Lift the cope and set it on a
pair of trestles.
Blow all loose sand from the cheek. Swab, rap and draw half of the
pattern from the cheek. Lift the cheek and set it on a pair of trestles.
bC^&^w?^J-
'mm;
m
tM
m
m\-
Fig. 110. — Mold closed.
Blow all loose sand from the drag. Swab, rap and draw the pattern
from the drag. Cut the gate in the drag, but make the riser connection
in the upper part of the cheek as shown in Fig. 110. Brush graphite on
the mold and set the cheek back on the drag. Set the core and make
the vent holes as shown at A. Close and clamp the mold as shown in
Fig. 110.
EXERCISE 18. MOLDING A MACHINE BASE
The base casting will be made in this exercise in a three-part flask
The pattern has parting hnes at A and B, Fig. Ill, and the core print,
C, is loose. A casting of this type should be poured from the bottom
through a step gate, as shown in Fig. 115. If the metal in the casting is
more than % in. thick sea coal must be used.
Fig. 111. — Machine base pattern.
Procedure in Molding
Place the core print and the drag on the molding board, as shown in
Fig. 112. Cover the core print and molding board with sifted sand,
or facing, if facing is being used. Fill the drag heaping full of unsifted
sand and peen-ram, then fill it heaping full and butt-ram. Strike off
the sand level with the top of the drag. Sprinkle on sand and rub down
the bottom board. Clamp and roll the drag over. Remove the clamps
Fig. 112. — Drag and core print placed on molding board.
and molding board. Place the pattern on the core print, as shown in
Fig. 113. Make the parting and apply parting sand.
Clay wash the inside of the cheek and place it on the drag. Set into
the drag a sprue pin that is long enough to reach to the top of the cheek.
Sift sand over the drag about }4 in. deep and set the gaggers. A, around
the pattern as shown in Fig. 113. Sift sand or facing over the pattern
to a depth of 1 in. Fill in with a layer of sand about 6 in. deep and
peen-ram. Put in another layer 6 in. deep, and peen-ram. Continue
ramming of layers until the sand is even with the top of the cheek.
94
FLOOR MOLDING EXERCISES
95
The last layer should be heaping full and butt-rammed to make a solid
parting. Make the parting and apph^ the parting sand.
Wet the inside of the cope with clay wash and set the sprue, cope and
riser as shown in Fig. 114. Sift sand into the cope and tuck it firmly
Fig. 113. — Cheek placed on drag.
under the bars. Fill the cope level full and peen-ram, then fill it heaping
full and butt-ram. Strike off the sand level with the top, and vent.
Draw the sprue pin and riser. Lift the cope and set it on a pair of
trestles.
Fig. 114. — Cope and sprue set.
Blow the loose sand from the cheek, swab around the pattern and
sprue, rap the pattern, and draw the sprue. Lift the cheek carefully
and set it on trestles. The pattern should remain on the drag when the
cheek is lifted; if it starts to rise with the cheek, rap it on top until it
will stay down.
Draw the pattern and the core print from the drag. Cut the gate
on the flange in the bottom of the cheek. Cut the two sprue connections
96
FOUNDRY WORK
on the top of the cheek. Make the vent hole for the core through the
bottom board. Set the core, then face the mold with graphite. Place
Fig. 115.— Mold closed.
the cheek back on the drag, taking care not to strike the core. Close
and clamp the mold as shown in Fig. 115.
EXERCISE 19. LIFTING A DRY-SAND CORE OUT OF
THE PATTERN
The mold in this exercise could be made without the use of a dry-
sand core, but trouble would be experienced by breaking sand when
lifting the cope. This trouble can be eliminated by the use of a dry-
sand core lifted out of the pattern with the cope. The core can be made
by using the pattern for the core box if desired.
Procedure in Molding
Place the pattern and drag on the molding board, ram, and roll over
as in the preceding exercises. Place the core in the pattern. Run
Fig. 116.— Mold closed.
a wire, strong enough to support the core, through the lifting hook in the
core, allowing it to stick out of the cope about 4 in. Ram the cope in
the usual way.
Before lifting the cope place a bar across it and fasten the wire to
this bar. Lift the cope and set it on a pair of trestles, without turning
it over. (If the cope is turned over the core may slide to one side.)
If there is any work or patching to be done, get under the cope to do it.
Draw the pattern and cut the gate. Close the mold as shown in Fig. ] 16
and clamp it.
97
EXERCISE 20. MOLDING A PLATE IN OPEN SAND
Plates that require only one smooth surface can be molded in open
sand and without the use of pattern or flask. Such molds are called
open-sand molds. Their use is limited to a very few shapes. In this
exercise only one method of making open-sand molds will be shown.
To make this mold it is necessary to have two guide boards, a straight-
edge and a spirit level.
Procedure in Molding
Build four mounds of molding sand on the foundry floor as shown
in Fig. 117. Place the two guide boards, B, on the mounds and
Fig. 117. — Beginning open sand mold.
level them in both directions. Shovel sand between the boards.
Ram the sand as in ramming a mold, being careful not to ram the guides
out of place.
Sift sand over the bed and ram it lightly not depressing it below the
guide boards. Strike off the sand level with the tops of the guides.
Test the bed to see that it is level and if it found to be out of level,
drive the guide again and again test for level. Repeat until the proper
condition is obtained. Sift a little molding sand over the bed through
a No. 8 riddle. Slick the sand down with a slick or trowel, being careful
not to develop hard spots.
Measure and mark off on the bed the size of the plate wanted. Then
use the board C, shown in Fig. 118, to build up the sides of the mold.
The board should have the thickness of the i)late to be made. Figure
118 shows two sides built up. After building up the sides make the
pouring basin as shown at D, Fig. 119. It should be built up a little
98
FLOOR MOLDING EXERCISES
99
higher than the sides of the mold, to give pressure when pouring.
Any open sand mold should be poured with hotter metal than molds
that are made with a cope, because there is no sprue used to give
Fig. 118. — Building up sides for open sand mold.
head pressure. Venting is done by running a long wire under the
mold. The vent holes should be left open as shown at E, Fig. 119.
Oi^^^A.
Fig. 119. — Open sand mold ready for pouring.
After the mold is poured and the metal has solidified, the casting
should be covered with molding sand which should remain until the
casting is removed from the mold.
EXERCISE 21. SWEEP MOLDING
Castings having circular forms can be made with sweeps instead of
patterns. When a few castings are to be made, if they are of such
nature that sweeps can be used, time in pattern making can be saved.
In this exercise a bowl will be molded by using sweeps. To make the
mold it is necessary to have the two sweeps, A and B, the spindle, C,
and the spindle-seat D, as shown in Fig. 120.
Fig. 120. — Sweeps, spindle and spindle seat.
Procedure in Molding
Place the spindle, in the seat, on the molding floor. Level the seat
so that the spindle is vertical. Level the floor with molding sand.
Pack molding sand around the spindle and ram it as firmly as a drag
is rammed. Place the sweep A on the spindle as shown in Fig. 121
7 i7 a
Fig. 121.— Spindle and sweep set Fig. 122.— Spindle and sweep placed
to sweep the sand for the outside of for cutting down the sand to make tho
the casting.
inside of the casting.
and revolve it to cut the sand to the desired shape which is the shape
of the outside of the casting. Remove the spindle and sweep. Put a
plug of wood into the spindle hole to prevent the sand from falling into
the seat. If the plug does not come even with the top of the mound,
100
FLOOR MOLDING EXERCISES
101
sand can be put over the plug. Put parting sand on the mound of
sand.
Clay wash the cope, set it over the mound and drive stakes into the
floor against the cope as shown in Fig. 123. These stakes take the
place of pins in guiding the cope when it is lifted. Set the gaggers,
place a flat sprue on the top of the mound, and ram as in the pre-
ceding exercises. Care must be taken in ramming the cope not to
ram the mound of sand out of shape. Vent the cope. Lift it and set
it on a pair of trestles.
Remove the wood plug and replace the spindle as shown in Fig. 122.
Put the sweep B, which is smaller than sweep A, on the spindle and
Fig. 123.— Mold closed.
revolve it to cut away the sand to give the required thickness of the
metal in the casting. Remove the sweep and spindle. Replace the
plug of wood in the spindle seat and fill the hole left by the spindle with
molding sand. Slick the sand in the cope and also in the hill, taking
care not to cause hard spots. Face the mold with graphite and replace
the cope over the drag.
A mold of this type cannot be clamped, but must be weighed down.
The amount of weight necessary to be placed on the cope can be com-
puted from the rule given on page 28.
Note. — Sometimes a green-sand core made in this manner will cause
blowing. The remedy is to place a cinder or coke bed on the floor
under the mold, providing pipes through which the steam and gases
can escape.
102 FOUNDRY WORK
EXERCISE 22. PIT MOLDING
Castings are sometimes made in a pit, instead of a flask.
In some cases the entire mold is made in the pit. In others
only the drag half is so made, an ordinary cope being used
above ground. The practice of pit molding is carried on
chiefly in making large castings and in jobbing shops
where the cost of building flasks would not be justified.
Complete patterns may or may not be used. Some molds
are formed by the use of sweeps and parts of patterns.
Others are built up entirely of dry sand cores.
Shops that practice pit molding regularly make perma-
nent pits, lining the sides with common brick. Shops that
make only an occasional pit mold usually fill the pit with
molding sand after the job is finished and use the space
for molding floor.
The cross section of a pit mold is shown in Fig. 124. The
drag half only is made in the pit. The casting is to be a
large collar or sleeve.
PROCEDURE IN MAKING THE MOLD
A pit is dug in the foundry floor, large enough to allow
for making the mold and for making a vent bed of cinders
or coke 6 in. deep, as shown at A, under the mold. After
the bed is prepared, vent pipes are placed as shown at B,
extending out of the pit from 4 to 6 in. The upper ends
are filled with waste to exclude sand when making the mold.
A layer of molding sand is put on the vent bed and
rammed. Vent holes are then run through the sand into
the bed as shown at C. Next the pattern is embedded in
the molding sand with the top even with the foundry floor.
The gate core, D, is put in place and a sprue pin, long
enough to come even with the top of the pattern, is set into
the gate hole in the core. The sides of the mold are rammed
in the usual way, the parting is made and the parting sand
applied. The cope, sprue and feeder are placed and the
guides E are driven. The cope is then finished in the usual
FLOOR MOLDING EXERCISES
103
way. The pattern and sprue pin are drawn from the pit,
the runner, F, and the feeder connection, G, are cut, and
the drag is finished as in floor molding. The core, H, is set
and the pipes running from the vent bed must be opened.
Fig. 124. — Pit mold closed.
FOUNDRY PROBLEMS
Some schools wish to go deeper into foundry practice
than the making of molds and dry sand cores and the
pouring of metals, by taking up problems from an executive
point of view. The following are examples of important
problems that must be solved by foundry executives. They
have been and are being used by the author in teaching
foundry practice.
Problem 1. — To lay out a floor plan for a small commercial
foundry. Some of the information can be had from the plan
shown in Fig. 3. The instructor should discuss, with the stu-
dent, the departments of the foundry and require him to show in
the plan where some of the principal pieces of equipment are to
be placed. He should also impress upon the student the necessity
for the plan to be practical and to provide for efficient operation.
Problem 2. — Cupola practice. The student should be given
dimensions for a cupola with the task of showing by cross-section
drawing how the cupola is to be charged when ready for the blast.
The method of charging should be specified by the instructor.
104 FOUNDRY WORK
Problem 3. — To compute the weight of a casting from a draw-
ing, to show by cross-section drawing how the casting is to be
molded, and to compute the weight necessary to hold down the
cope.
Problem 4. — To compute an iron mixture from chemical analysis.
To make up charges to fit the cupola shown in Exercise 2. To
compute the summary after the heat has been poured, taking into
consideration: The amounts of the different kinds of metal used;
the good and bad castings made; the amount of metal in the sprues
and risers; the iron loss in melting; the iron and coke recovered
from the dump; and the melting ratio. To test the metal for
strength, deflection, shrinkage and chill. To compute the cost per
pound of the castings. The data are obtained from the exercise.
Note. — The data in regard to good and bad castings, the iron in
sprues and risers, and the iron and coke in the dump must be
furnished the student. They can be taken from general practice,
but it is preferable if the heat actually can be run by the student.
Problem 5. — The student should be given a pattern with the
task of designing a flask that will be suitable for making the
mold, and of showing, by cross-section drawing, the mold ready for
pouring.
Problem 6. — Defective casting report. For this exercise the in-
structor should collect a group of defective castings and have the
student make a report on them. The student should state the
causes of the defects and tell how to prevent such defects.
Problem 7. — The student is to show in graphic form how
the organization is going to function when the foundry that he
planned is put into operation, and to select some of the principal
pieces of equipment.
Note. — The information necessary in selecting equipment can be
had from trade catalogues.
Problem 8. — The student is given a pattern and is required
to calculate the weight of the casting to be made from it. He
is then to check his calculation by weighing the pattern.
FIRST EXERCISE— FOUNDRY LAYOUT
Rooms, Storage Bins and Yards Required
Molding room for twelve molders
Cupola room
Cleaning room for cleaning castings
Core room for making dry-sand cores
Pattern storage room
Tool and supply room
Motor and blower room
Office
Coke shed
Molding sand shed
Core sand shed
Clay shed
Sea coal facing shed
Iron yard
Flask yard
Railroad siding
Specifications
(a) Base the molding floor space on 800 sq. ft. to 1 ton of good cast-
ings.
(b) One molder should make 500 lb. of good castings per day.
(c) One molder will need a molding floor 25 ft. long and 8 ft. wide.
(d) The main gangways in the molding room should be from 6 to 8
ft. wide.
(e) When laying out the floor plan use a scale of i^g in. to 1 ft.
Notes
The layout specified is that of a typical small commercial shop.
Any additional rooms, sheds, or yards may be added if thought
to be desirable and practical.
In this layout it is very important that considerable attention be
given to the routing of the iron from the storage yard to the finished
casting.
105
SECOND EXERCISE— CUPOLA PRACTICE
Cupola Dimensions
Diameter of cupola shell 52 in.
Thickness of Hning 7J4 in.
Inside diameter at tuyeres 37 in.
Height from bottom plate to bottom of charging door 12 ft.
Height from bottom plate to bottom of tuyeres 15 in.
Height from sand bottom (back side) to bottom of tuyeres. . 9 in.
Height from sand bottom (at spout) to bottom of tuyeres ... 1 1 in.
Number of tuyeres in cupola 6
Size of tuyeres at inside of hning 4)^ in. high, 8 in. wide
Notes and Instructions
1. 1 lb. of coke will occupy about 65 cu. in. when charged in a cupola.
2. 1 lb. of iron will occupy about 9 cu. in. when charged in a cupola.
3. Make the first charge or bed of coke 22 in. above the top of the
tuyeres.
4. Charge 2J^ lb. of iron to 1 lb. of coke on the first charge, or bed.
5. Use a 9 in. layer of coke between layers of iron.
6. Charge 10 lb. of iron to 1 lb. of coke on the charges above the bed.
7. A "charge" means a layer of coke, together with the layer of
iron directly above it.
8. In computing a coke charge make it the nearest multiple of 10 lb.
Example: If the result obtained is 128 lb. make it 130 lb.
9. In computing an iron charge make it the nearest multiple of 25 lb.
Example: If the result obtained is 910 lb., make it 900 lb.
10. In computing the thickness of an iron charge, make it the nearest
multiple of a half-inch.
11. Compute and enter on the drawing the additional amounts of
iron and coke required to complete the heat of five tons of iron.
12. In making the cupola sketch use a scale: 3^ in.-l ft.
Note. — The dimensions and figures given here may be varied at the
discretion of the instructor.
106
THIRD EXERCISE
1. The drawing gives the dimensions of a casting and of the flask
in which it is molded. Make a drawing similar to that shown, using
the scale given.
2. Compute the weight of the casting and enter it on the drawing.
A cubic inch of cast iron weighs 0.26 lb.
1
1
I.
1
A
1
1
<---2e ]->
5t
}-
^
L
J
^
r
<-
jr'—-
->
N
'tW
Flask 4G"jcfuare
->|7K 4G
— g] ^
Seclion -fhrou^h Mold
Fig. 124A.— Pattern and mold.
3. Compute the weight required to hold down the cope while the mold
is poured, and enter it on the drawing.
When a mold is poured, the fluid metal exerts a pressure similar to
a hydraulic pressure and can be expressed in the same way (in pounds
per square inch). Obviously the pressure which will tend to raise the
cope is that exerted on the top surface of the mold, hence the pressure
on the bottom and sides of the mold may be disregarded.
107
108 FOUNDRY WORK
The pressure per square inch on any surface of the mold is equal to
the distance in inches from the given surface to the top of the cope,
multiplied by 0.26. The total force hfting up on any surface is then
equal to the pressure per square inch multiplied by the number of
square inches of surface. The total force lifting up on the cope is the
total of the hfting forces on all the top surfaces of the mold. This
total force may be computed in another way, by obtaining the total
volume in cubic inches of the space between the pattern and the top
of the cope, and multiplying this figure by 0.26.
The upward force may be partly or entirely balanced by the weight
of the cope. This weight may be computed by obtaining the number
of cubic inches of sand in the cope and multiplying this number by
0.06 lb., the weight of a cubic inch of rammed molding sand. Use the
inside dimensions of the flask, neglecting the weight of the flask itself,
and figure the cope as solid sand, disregarding the sprue and riser, bars,
and gaggers.
The weight required is the total upward pressure minus the weight
of the cope.
FOURTH EXERCISE
1. Compute mixture.
2. Fill in cupola dimensions from Exercise 2.
3. Compute the ratio of tuyere area to area of the cupola.
The combined tuyere area equals the product of the number of
tuyeres times the height, Limes the width of each tuyere.
The horizontal cross-sectional area of the cupola is the area of a circle
whose diameter is the inside diameter of the cupola.
4. Fill in charging sheet according to iron mixture and cupola charges
computed in Exercise 2. Start charging flux on the fourth charge,
5. When computing the summary the iron recovered from the dump
is regarded as iron not melted. The percentages of iron taken from the
dump, good and bad castings, sprues and risers, and iron lost in melting,
should total 100 per cent, and the percentages are based on total
metal charged as 100 per cent. The iron taken from the cupola and
the iron lost in melting should also total 100 per cent, and their per-
centages are also based on total metal charged.
The melting ratio is obtained by dividing the number of pounds
total metal melted by the number of pounds of coke burned in melting.
6. Break the test bars to obtain the breaking load and deflection.
Average the results for the two bars. To find the transverse strength
in pounds per square inch divide the breaking load by the area of the
fracture in square inches.
To find the shrinkage measure the difference between the lengths
of the pattern or shrinkage clamp and the casting.
To find the depth of chill measure the thickness of the white portion
in the fracture of the chilled bar.
7. Compute the various items of cost on the basis of one day's
operation, and from these the cost of the castings per pound.
8. Fill in your name, bench number, period, hours spent on the
exercise, and date in the spaces provided at the bottom of the sheet.
109
FOURTH EXERCISE
Sheet 1
Analyses of Iron in Stock
No. 1 Pig Iron
No. 2 Pig Iron
Scrap Iron
Per cent
Per cent
Per cent
Carbon 4
Carbon 3 . 75
Carbon 3 . 5
Silicon 3 . 1
Sihcon 2 . 75
Sihcon 2 . 1
Manganese . 8
Manganese . 6
Manganese . 5
Phosphorus . 9
Phosphorus . 5
Phosphorus . 6
Sulphur 0.03
Sulphur . 05
Sulphur 0.07
Analysis Required in Castings
Per cent
Carbon from 3.6 to 3.8
Silicon from 2.25 to 2.5
Manganese from 0.5 to 0.6
Phosphorus from 0.6 to . 7
Sulphur not over 0.1
Sihcon loss in melting about 0.25
Manganese loss in melting about . 1
Sulphur increase in melting about . 03
Carbon and phosphorus remain ap-
[)roximately constant.
Mixtures Computed in 1,000 Lb.
Charges
Carbon
No. 1 Pig Iron
No. 2 Pig Iron
Scrap Iron
Total
lb.
lb.
lb.
lb.
C
c
c
c
Silicon
..lb.
..lb.
..lb.
..lb. = ....
. . . Per cent
No. 1 Pig Iron
No. 2 Pig Iron
Scrap Iron
Total
lb.
lb.
lb.
lb.
Si
Si
Si
Si ;.
..lb.
..lb.
..lb.
. . lb. = . . . .
. . . Per cent
Loss in melting
. . . Per cent
. . . Per cent
110
ganese
Mn
...lb
Mn
...lb.
Mn
...lb.
Mn
...lb. =
No. 1 Pig Iron lb.
No. 2 Pig Iron lb.
Scrap Iron lb.
Total lb. Mn lb. = Per cent
Loss in melting Per cent
Per cent
No. 1 Pig Iron .
No. 2 Pig Iron .
Scrap Iron
Total
Phosphorus
lb.
P
...lb.
lb.
P
.. .lb.
lb.
P
. . .lb.
lb.
P
Sulphur
. .lb. = ...
.... Per cent
lb.
S
. . .lb.
lb.
S
...lb.
lb.
S
. . .lb.
lb.
S
. . .lb. = ...
.... Per cent
No. 1 Pig Iron
No. 2 Pig Iron
Scrap Iron
Total
Gain in melting Per cent
Per cent
Name
Ill
FOURTH EXERCISE
Sheet 2
Dimensions of Cupola
Size of cupola shell
Thickness of hning
Inside diameter at tuyeres
Height from bottom plate to bottom of charging door
Height from bottom plate to bottom of tuyeres
Height from sand bottom (back side) to bottom of tuyeres
Height from sand bottom (at spout) to bottom of tuyeres
Number of tuyeres in cupola 6
Size of tuyeres at inside of lining in, high; in. wide
What is the ratio in per cent of the combined tuyere area to the
horizontal cross-sectional area of the cupola per cent
Weight of Charges in Pounds
No. of
Charges
Fuel Coke
No. 1 Pig
No. 2 Pig
Scrap Iron
Flux
1st or bed
2nd
3rd
4th
5th
6th
7th
8th
9th
10th
Total
112
Summary
No. 1 pig iron charged .
No. 2 pig iron charged .
Scrap iron charged . . .
Total metal charged . .
Iron recovered frum
dump
Total iron melted . . . .
Good castings made . .
Bad castings made . . .
Returned sprues, risers,
etc
Lb.
Per
cent
3.0
60.0
2.5
26.5
Iron taken from cupola
Iron lost in melting. . .
Fuel
Coke charged
Coke recovered from
dump
Coke burnt in melting
Melting ratio, .lb.
iron to 1 lb. coke . .
Lb.
100
Per
cent
Test of Iron
Size of bar, 1.25 in. in dia., 15 in. long. Tested 12 in. between supports.
Load applied in center. Bar broke at lb.
Transverse strength lb. per sq. in. Deflection in.
Shrinkage: Bar 1 in. square, 12 in. long. Shrinkage in. per ft.
Chill: Bar 1 in. square, 6 in. long. Depth of chill in.
Name
li:
FOURTH EXERCISE
Sheet 3
Cost of Metals, Coke, and Flux
No. 1 pig iron per ton of 2,240 lb.
No. 2 pig iron per ton of 2,240 lb.
Scrap iron per ton of 2,000 lb.
Coke per ton of 2,000 lb.
Flux per ton of 2,000 lb.
Cost of Iron in Heat
lb. No. 1 pig iron at i per lb. $
lb. No. 2 pig iron at i per lb. $
lb. scrap iron at i per lb. $
Totals
Deduct the value of iron returned as sprues, bad castings,
and iron in dump, at the price of scrap iron, lb.
at ^ per lb $
Net cost of metal in castings $
Cost of Melting
lb. coke to melt iron, at i per lb $
lb. flux, at ^ per lb $
1 melter at per day $
1 man to make up charges at per day $
Total cost of melting $
Cost of Molding, Coremaking, and Cleaning Castings
12 molders at per day $
2 coremakers at per day $
4 laborers at per day $
Total labor $
Overhead: allow 100% of labor cost $
Total
Cost of Castings
Metal $.
Melting $ .
Molding, coremaking, cleaning, and overhead ...%.
Total. .$.
Cost of castings per ton of 2,000 lb $ .
Cost of castings per lb $.
114
Overhead Expense
Overhead expense includes cost of power, heat, light, water, taxes,
insurance, interest on investment, depreciation on buildings and
equipment, repairs, office salaries, office supplies, telephone charges,
supervision of labor, trucking, express, freight, miscellaneous foundry
supplies such as sands, sea coal, graphite, clays, and core-binders,
tools for molding and coremaking, and miscellaneous materials.
115
FIFTH EXERCISE— FLASK DESIGN
1. Design a flask suitable for molding the casting specified, making
proper allowance of space for gating and for sand between the pattern
and flask on the sides, top, and bottom.
2. Show in the sketch one end view and one side view of the flask.
3. Name each part of the flask and enter dimensions on the sketch.
4. Show a cross-section of the mold ready for pouring, with gates
cut and core set in place.
116
SIXTH EXERCISE— DEFECTIVE CASTING REPORT
1. Rule up a sheet of paper similar to the one posted, and list the
castings as shown there.
2. Examine each casting carefully and determine the cause of its
defect.
3. After analyzing the defect explain how to prevent it.
117
SEVENTH EXERCISE
1. Form a working organization to operate the foundry that you
planned.
2. Show in a graphic way how it operates.
3. Select the principal equipment needed for operating the foundry.
lis
EIGHTH EXERCISE
Compute the weight of the casting when cast in gray iron. Hand
in the computations on a sheet of ruled paper hke that mentioned in
Exercise 6. Multiphcations need not be carried out in full, but may
be indicated on this sheet.
1. Compute the weight by the method of Exercise 3.
2. Compute the weight from the weight of the pattern. First
weigh the pattern. A cubic inch of white pine weighs about 0.0144 lb.
Gray cast iron is about eighteen times as heavy as white pine. In
this method of computation, deduction must be made for cored holes
and for core prints on the pattern.
119
CHAPTER XII
METAL PATTERNS, FOLLOW BOARDS, MATCH
PLATES
The molds described in Chaps. X and XI were made by
hand, partings and gates had to be cut, and the patterns
were drawn one at a time. Those methods are slow and
are used only when a few castings are to be made from a
pattern or when fundamental principles are to be taught.
The method of molding by hand, called the Egyptian
method, has been in use many years and still is being used.
One might think that there has been no progress made in
the manufacture of castings, but such is not the case.
There have been quite extensive improvements over the
few-castings method, in making castings on a ''production"
scale. However, the pattern equipments are expensive and
it would not be practical to fit up patterns for the produc-
tion method when only a few castings are wanted.
Metal Patterns. — Metal patterns give better service
than wooden patterns, especially when in continuous use.
They not only will last longer but they will keep their
shape better and remain smoother than wooden patterns,
advantages that are important in production work. Metal
patterns may be made of aluminum, brass, white-metal or
iron. The best kind of metal to use for a given kind of
pattern depends upon the size and shape of the pattern.
Alloys with aluminum predominating are good metals to
use for making small patterns, because they are not heavy
and are easy to finish.
When making metal patterns a master pattern must be
made first, either of wood or of some other material that
can be shaped without much expense. From the master
120
FOLLOW BOARDS
121
pattern the metal pattern is molded. After the metal pat-
terns are made they can be attached to gates as shown in
Fig. 125.
Fig. 125. — Gated metal patterns.
Follow Boards. — Much time can be saved by using fol-
low boards instead of flat molding boards. Figure 126
shows the follow board to use with pattern shown in Fig.
125. If a flat molding board were used with a pattern of
this type, much time would have to be spent in making
^^^^^^M
M
%
r
.. -^
Fig. 126.— Follow board.
the parting. With the use of the follow board, no parting
need be cut, because the patterns lie in the board only as
far as the parting line. When using a follow board, the
patterns are placed on it and the drag is rammed in the
usual way. After the drag is rolled over, the follow board
122 FOUNDRY WORK
is lifted off and the parting is ready. The mold is then
completed in the usual manner.
Follow boards may be made of wood by carving the
board in such a manner that the patterns will lie in it to
the parting line, or they can be made of oil sand or plaster
of Paris. For small patterns oil-sand followers are usually
used.
To make the jollower shown in Fig. 126. A frame that
has the required depth for the pattern must be made first
as must a board to lit the frame. Place the pattern and
drag on a flat molding board with the drag raised to be
even with the parting line. Ram the drag a little harder
than is necessary in making a mold. Roll the drag over
and cut down the sand around the pattern to the parting
line. Dust some parting material on the pattern and drag.
Lycopodium makes the best parting material for oil-sand
work.
A good sand to use for making the follower is burned
sand that has been rattled from castings". Measure out
the required amount of sand and mix it with the litharge
in the ratio of one part of litharge to from twenty to thirty
parts of sand. Moisten the mixture with linseed oily mak-
ing it slightly damper than sand ordinarily used" for
molding, taking care not to get it too wet.
Place the frame on the drag and sift the oil-sand mixture
over the patterns to cover them. Then fill the frame heap-
ing full with the oil sand and ram it about as hard as a
mold is rammed. Strike off the sand even with the frame
and fasten the board to the frame, with wood screws.
Clamp the follower and drag together and roll them over.
Lift the drag from the follower and clean all loose sand
from the patterns. Should the oil sand be rammed below
or above the parting line on the pattern, build it up or
cut it down. Rap the patterns and draw them from the
follower carefully, so that the sand around them will not
break. Slick down the sand that may have been loosened.
Tlie follower should be set in a warm place, where it
MATCH PLATES
123
will dry in about 24 hr. After it is dry, give it two or
three coats of thin shellac, which will make the sand
stronger and more capable of withstanding wear. Oil-sand
followers will last for many years in continual use if they
are handled carefully. They can be kept in storage suc-
cessfully.
Match Plates. — The mounting of patterns and gates on
plates is another method used to increase production. Pat-
terns fastened on plates not only will increase production
but will hold their shape better than loose patterns, and
usually the castings made from them are more uniform in
size. The objection to plated patterns is the high cost of
Fig. 127. — Face plate patterns mounted on plate.
mounting them, and therefore they are made only when a
large number of castings is wanted.
The patterns may be mounted on boards, but wood is
not very serviceable for the work because of its tendency
to warp. Steel plates about %o ii^- thick or aluminum
plates about ^/4 in. thick are much more serviceable. The
mounting is a very particular job and is usually done by
metal pattern makers.
A plate with the patterns and gates on one side is shown
in Fig. 127. The fact that the patterns are drafted in one
direction makes possible their mounting on one side of the
plate. The pattern side should be used in the drag and the
flat side in the cope.
A plate with patterns mounted on both sides is shown
in Figs. 128 and 129. The patterns are split on the parting
line, one half being fastened to one side and the other half
124
FOUNDRY WORK
to the opposite side of the plate. The gate is on the drag
side.
When mounting patterns on both sides of the plate, the
two halves must be directly opposite; otherwise there will
be a shift in the castings.
Fig. 128. — Drag side of match plate.
A pattern with an irregular parting line, mounted on a
plate, is shown in Fig. 130. To mount this pattern, it is
necessary to mold the pattern and plate in one casting and
then finish the casting for a pattern.
Fig. 129. — Cope side of niatcii plate.
To Mold the Plate. — Select a flask with good, smooth
joints, about 4 in. wider and 12 in. longer than the plate
to be made. The pins must fit in the guides. Place the
cope on a board with the pins up. Fill the cope with sand
and ram it about as hard as in ramming a mold. Strike
MATCH PLATES
125
off the sand level with the joint of the flask. Embed the
pattern in the sand to the parting line, centering it with
respects to the sides and ends of the core.
Place the drag on the cope and ram it in the usual way.
After the drag is rolled over, remove the cope and shake
Fig. 130. — Propeller matrh plate.
it out. Carefully make the parting. Dust some parting
material (lycopodium is the best) on the drag. Place the
cope and set one sprue at each end of the pattern about
3 in. from the end of the flask. Ram the cope, being careful
not to ram the sand in the drag out of place. Lift the cope
Fiu. 131.
and set it on a board. If any of the sand sticks down when
the cope is lifted, another cope should be rammed, instead
of patching the broken one.
Make a frame the size of the plate and lay it on the
drag. Build up the sand around the frame as shown in
126 FOUNDRY WORK
Fig. 131. Swab the sand around the frame and draw the
frame from the drag. Blow all the loose sand from the
mold. Then swab around the pattern and draw it from the
drag. Cut the gate that is to run the casting to be made
from the plate, in the drag. Cut the gates that are to run
the plate at the ends of the mold. Put a little thin flour
paste on the sand that was built up around the frame, to
help make a tight joint when the mold is closed. Close the
mold, but before clamping it, wet the outside of the flask
at the joint and tuck some wet molding sand between the
cope and the drag to further improve the tightness of the
joint.
CHAPTER XIII
MOLDING MACHINES
Molding machines are used extensively by foundries
carrying on production work. The castings made on them
are usually more uniform in size and shape than those
made by hand. Production often is increased 100 per cent
by their use. Less skill is required with machines and
unskilled labor can be better employed, in itself an impor-
tant factor on production work. While there are many
special machines in use, it may be considered that there
Fig. 132. — Hand squeezer type molding machine.
are four general types, which will be considered in this
chapter.
Squeezer Machines. — The machines generally used to
make small castings are called ''squeezers." They arc
built in stationary and portable types, operated either by
hand or by air. A portable hand-operated machine is
shown in Fig. 132 in which A indicates the squeezer table,
B the head or yoke, C the handle used in squeezing the
mold, and D the shelf upon which the flask and patterns
are set.
127
128 FOUNDRY WORK
The squeezer and bottom boards should be made smaller
than the inside of the flask by % ^^-^ so that they will enter
the flask freely. Snap flasks are used on the squeezer as a
rule, although other types may be employed. A button
correctly located and of the proper shape and size to leave
a funnel-shaped depression where the sprue hole is to be
cut, should be fastened to the squeezer board.
Almost any one can learn to operate a squeezer in a very
short time and to do good work, especially when the pat-
terns are mounted on a plate.
To Make a Mold on the Machines. — Place the match-
plate between the cope and the drag on the table, A. Cover
the pattern with sifted sand. Tuck the sand around the
flask next to the match-plate. Then fill the drag level full
of sand and place the bottom board. Tap the bottom board
down a little, making certain that it enters the flask. Roll
the drag over, without squeezing.
Cover the pattern in the cope with sifted sand and fill
the cope level full of heap sand. Place the squeezer board
on the top of the mold. Pull the yoke, B, over the flask
and squeeze the mold by pulling down the handle, C.
Remove the squeezer board and cut the sprue hole. Rap
the plate on the corners with either a wooden or raw-hide
mallet. Lift the cope and set it on the shelf. Rap the
plate and draw it from the drag.
Close the mold and remove the flask. Set the mold on
the floor where it is to be poured. Brush off with the hand
the rough edge of sand left around the top of the mold.
Before pouring slip a jacket over the mold and weight it
down.
Stripping-plate Machines. — Stripping-plate machines
are adapted to a great variety of castings. They are
exceedingly simple to operate which is an advantage when
using inexperienced men. Stripping a pattern through a
plate is one of the best methods known for producing cast-
ings true to pattern. In order to make some castings these
machines must be worked in pairs. A pair of machines
MOLDING MACHINES
129
used to make brake shoes is shown in Fig. 133, where B
indicates the machine used to make the cope.
Fig. 133. — Stripping plate molding machines. A for making drag and B for
making cope.
To Make the Mold. — Place a drag on machine A and
ram it as in hand molding. Then draw the pattern by
Fig. 134. — Hand roll-over molding machine.
pulling down the lever C. Lift the drag from the machine
and set it where it is to be poured. Place the cope on
machine B, ram it, and draw the pattern by pulling down
130
FOUNDRY WORK
on the lever C. Lift the cope from the machine and set it
on the drag. Clamp the mold and it is ready for pouring.
Roll-over Machine. — A roll-over, or rock-over machine
with the pattern of a pulley ready to be molded is shown
in Fig. 134.
To Make the Mold. — Place the drag over the pattern, A,
supported on the plate, C, and ram it. Put a bottom board
on the drag and clamp board and drag to plate. Roll the
plate and drag over to the other side of the machine where
the bottom board will rest on the stand, D, which has been
adjusted to the depth of the flask. Remove the clamps and
Fig. 135. — Air power jar molding machine.
drop the stand, thereby withdrawing the mold, B, from the
pattern. Place the drag where it is to be poured and set
the dry-sand core in it. Roll the pattern back to its first
position. Place the cope over the pattern and set the sprue
either on the hub or between the arms. Ram the cope and
roll it over as the drag was rolled. Draw the cope from
the pattern, place it on the drag, and clamp the two. Roll
the pattern back to the first position, and it is ready for
the next mold.
Jarring Machines. — A simple jarring machine, that can
be used for ramming either molds or cores is shown in Pig.
MOLDING MACHINES 131
135. Jarring machines are usually set on a solid foundation
in a pit, with the table, A, raised slightly above the floor
level. The machine shown is operated by air.
Ramming a mold on a jarring machine is very simple and
requires no skill. The pattern and flask are set on the table.
Then the pattern is covered with sifted sand and the drag
is filled heaping full of unsifted sand. The air is then
turned on. When it enters the cylinder the table is raised
and when it exhausts the table falls. The result of the
rising and falling motion is to jar the mold. The constant
repetition of the jarring action for a short time produces a
mold evenly rammed.
The number of strokes, the length of the strokes and the
time required to pack the sand to sufficient density depend
upon the size of the mold and the shape of the casting,
and a knowledge of them must be gained by experience in
actual practice.
CHAPTER XIV
DRY-SAND CORE MAKING
Dry-sand core making is a branch of foundry business
and is more important tlian molding in the manufacture of
some castings. It is regarded as a trade in itself. Dry-
sand cores are used to make any desired hole or cavity in
castings that cannot be made with green-sand cores.
COMPOSITION OF CORES
Cores are made of different kinds of sands mixed with a
binder which holds the individual~sand grains together and
hardens under the application of heat. The chief qualities
to be sought after in cores are: strength, to retain the origi-
nal form when submitted to the high temperatures of the
molten metal; porosity, to permit a free vent for the gases
formed when the melted metal comes in contact with the
core surface; and smoothness, to leave the surface on the
casting as nearly as possible in a finished condition.
The strength of the core depends upon the sharpness of
the corners of the individual grains of sand and the cement-
ing quality of the binder. Sand grains with rounded cor-
ners are an aid to porosity but weaken the core through
the absence of the locking effect of sharp corners. Sand
that is too coarse makes a core with a rough surface and
hence a casting that is not very smooth. A fine sharp sand,
therefore, held together by a binder which does not form a
solid mass, makes the best core. A binder such as referred
to will collect at the contact points of the grains while
hardening, thus making a porous interior. Some of the
mixtures that have proved satisfactory are as follows:
132
DRY'S AND CORE MAKING 133
Mixture 1. — For small castings. Vents freely. Forty
parts fine sharp sand to one part linseed
core oil.
Mixture 2. — For small castings. Vents well but not as
freely as Mixture 1.
Fifteen parts new fine-grained molding sand,
Five parts fine-grained sand.
Twenty parts of the above sand mixture to
one part of linseed oil, or one and one-half
parts resin. AVet with water.
Mixture 3. — For medium-sized castings.
Ten parts sharp sand
Five parts new molding sand
One part wheat flour or one part core com-
pound. Wet with thin clay wash.
Mixture 4. — For heavy castings.
Thirty parts sharp sand
Ten parts new molding sand
One part dry core compound, one part "glu-
trin."=^
Wet with clay wash.
It is assumed that the sharp sand for small castings
mixtures has the quality of Lake Michigan sand found
around Michigan City. Tnd.. For larger castings a sand of
coarser grain should be used. In general a sharp sand
requires less binder than a dull sand.
The proportions of all of the mixtures noted above are
given by volume.
In some foundries equal parts of old core sand are added
to the mixture of new sharp and new molding sand, thus:
To fifteen parts sharp sand and ten parts of new molding
sand, there would be added twenty-five parts old core sand.
In some localities sand is found that has the proper pro-
portion of sharp sand and clay, and no sharp or new mold-
ing sand need be added to it for a core mixture.
* Trade name.
134 FOUNDRY WORK
Binders may be divided into two general classifications:
First, those that do not flow to the contact points of the
grains. These are sometimes called pastes. Flour and
dextrine mixtures are of this type. Second, those that flow
to the contact point of the grain. They are sometimes
called binders. Molasses, ''glutrin"^'* and certain oils are
examples.
Resin and pitch also are used occasionally as binders.
Oils make the most satisfactory binders for small cores.
They are strong and do not absorb moisture.
A baking temperature that is too low does not harden the
binder, while a temperature that is too high burns it and
weakens the core.
Care must be taken in the amount of binder used. Too
much binder makes a hard core, which frequently causes
defective castings. Too little binder makes the core soft
and a soft core will crumble.
Cores may be surfaced by coating them with graphite,
which assists them in withstanding the temperatures to
which they are subjected. It also improves the surface
of the core and therefore the surface of the hole in the
casting. To make the graphite-paint mixture, add water
to the powdered graphite to form a paste, then thin down
with water to a paint, after which add one teaspoonful of
molasses per pint. The cores may be dipped, brushed or
sprayed.
CORE BOXES, SWEEPS AND CORE PLATES
Cores are shaped by any one or a combination of three
methods, i.e., by the use of specially prepared core boxes;
by employing sweeps; and by means of patterns used as
core boxes.
The use of specially prepared core boxes is the most
common method for small cores. The boxes generally are
made of wood, iron, aluminum, brass or plaster of paris.
* Trade name.
DRY-SAND CORE MAKING
135
Cores of cylindrical shape may be made by using sweeps.
When the expense of making a special core box is too great
and the pattern is of the proper form and strength, it may
be used as a core box.
CORE PLATES
Iron core plates, such as shown at A, Fig. 136, are used
for handling and baking cores. Straight plates are common
for cores that have a flat side to rest on, such as cylinder
cores made in halves, but forms of special shapes are
required for irregular cores. Sometimes fiat plates may be
used where the irregularities can be supported during the
Fig. 136. — Core plates and core dryer.
baking process by green molding sand, built up under or
around the core as shown at B. When the core is baked
the molding sand peels off easily.
If molding sand is not packed under the cores, core
dryers are used. The illustration, at C, shows a core rest-
ing in a dryer. Core dryers are made of iron and they must
have the exact shape of the cores with which they are used.
RAMMING
Some core mixtures may be rammed harder than others.
The amount of ramming will depend upon the amount of
loam in the mixture, size of the core, and the size of the
individual sand grains. Loam mixtures pack harder and
vent less freely than sand mixtures. Therefore mixture 1,
consisting entirely of sharp sand, may be rammed harder
than mixture 2, without causing any bad results. Ramming
136
FOUNDRY WORK
the sand too hard causes it to stick to the boxes and makes
drawing difficult. If the core is too lightly rammed, it
will be porous and the metal will eat into it, causing a
rough surface on the casting. The ideal core is one with
a smooth, reasonably firm surface and a porous interior.
VENTING CORES
One of the most important features of the core is its
venting qualities. When the metal comes in contact with
them, all dry-sand cores give off gas, which must be led out
of the mold, for reasons previously given. The amount of
gas liberated depends largely upon the sand and the binder
Fig. 137. — Shows a roll of vent wax.
used. Wheat flour is a gaseous binder, while resin and oils
are less so.
In some of the simple cores venting is easily done, but
on the more intricate ones it becomes a difficult problem.
A small round core made in a round box may be vented
by running a vent rod through its center after ramming.
A core made in halves may be vented by cutting a channel
through the center of each face of the main section, and
laterals in the lesser sections, leading from the channel to
the surfaces of the core. When the halves are pasted, the
channels must match.
In some intricate cores where a wire cannot be used, or
where a channel cannot be made, a vent wax, as shown in
Fig. 137, is used. Vent wax may be purchased from the
foundry supply houses. It is embedded in the sand along
DRY-SAND CORE MAKING
137
the line or lines that the escaping gas is to follow. When
the core is baked, the wax melts and disappears between
the sand grains, leaving the vent channels desired.
Where it can be used, a perforated pipe, such as described
under ''Rodding," makes one of the best possible vent
channels.
Many large cores are made with center of coke, cinders,
or some similar material. These substances give porosity
and lightness to the core and save much sand, which in
large castings is a point of considerable importance.
ROBBING CORES
Some cores are subjected to more or less bending during
the setting and pouring processes. Vertical cores undergo
Fig. 138. — Shows dry sand cores supported with a pipe at A and a core
arbor on the inside of the core at B.
the least strain and horizontal cores the greatest. Assum-
ing careful handling in setting, deflection may be caused
by the weight of the core; the floating action of the metal;
or by the dynamic force of the metal when a mold is filled
quickly.
The exact pressure exerted in any mold cannot be deter-
mined, but to insure a core that will retain its shape under
all conditions, the core-maker reinforces his core by rodding
it. What size of rod to use is something that must be
learned by experience. The rods may vary between %6 in.
and 3 in. in diameter. Figure 138 shows at A, a core
rodded with a pipe perforated by small holes, which makes
an ideal stiffener and at the same time provides excellent
channels for outlet of gas.
138
FOUNDRY WORK
In some large cores, arbors are used. They are shaped
to suit the core and serve not only to strengthen but to save
sand. A cylindrical core made with an arbor is shown at
B. Rods or pipes will hold the sand better if coated with
clay wash or flour paste.
LIFTING HOOKS
Some cores are of such shape and weight that it would
be impossible to handle and set them in the mold if they
were not provided with lifting hooks or eyes. The core
maker must inform himself before making the core just
how it is intended to be handled. There are many kinds
of hooks used. Generally they are made of iron and the
Fig. 139. — lifting liooks and lifting plate for lifting core.
size depends upon the weight of the core to be supported.
A U-shaped hook used extensively for small and medium
sized cores, is shown at A, Fig. 139. The lifting plate and
screw, shown at BB, are used for larger cores.
Hooks and plates must be so placed that the core will
balance when it is lifted. All depressions made to accom-
modate the hooks must be filled after the core is set.
PASTING AND DAUBING CORES
When cores are made in sections, the parts must be
assembled before they are set in the mold. In the assem-
bling process the sections are cemented together at the
jointed surfaces with a good coat of thin paste, the sections
being rubbed together to secure a good face contact, or
tied together by wire or other fastening if necessary. The
DRY-SAND CORE MAKING
139
cores are then inserted in the oven during a period of time
for the paste to dry.
A number of good commercial core pastes may be ob-
tained but an inexpensive and very satisfactory paste is
made of wheat flour dissolved in cold water.
After cores are assembled and baked all open joints
should be filled to insure a smooth casting. This process
is called daubing. A good daubing substance can be made
by mixing graphite in water to the consistency of a stiff
paste. A little molasses put into the w^ater will add to
Fig. 140. — Two half core pasted together.
the sticking qualities. A better mixture consists of graphite
in oil. Figure 140 shows the halves of a core before and
after pasting. The assembled core has the joints daubed
and is ready to be set in the mold.
CORE OVENS AND BAKING
Core ovens are of many types and may be portable or
stationary. The kind to be used depends upon the size of
the cores to be made. For baking small cores, ovens of the
type shown in Fig. 141 have worked out successfully. They
are portable, with built-in fire boxes. The shelves are con-
nected with the doors, so that when the doors are opened
the cores are drawn out. A plate attached to the back of
each shelf closes the opening to the fire box, preventing the
waste of heat when the cores are taken from the oven.
A stationary combination type of oven is shown in Fig.
142. It is an oven that can be used for either small or large
cores. One side contains the roller type of shelves and the
140
FOUNDRY WORK
other side is arranged to accommodate a truck. Large
cores are usually made on the truck, which is then pushed
H ^'^^ — i
<^sii#^"miu£j|
Fig. 141. — Core oven for baking small cores.
Fig. 14'
-Core oven lor leaking small <n- large corc.^
into the oven. The truck may be used to hold a large
quantity of small cores. The combination oven can be
purchased in any size desired.
DRY-SAND CORE MAKING 141
All core ovens should be connected to chimneys. Coke,
coal, gas, crude oil, or electricity may be used for heating
them. Coke is the most economical fuel.
Core ovens are generally heated from 300 to 600 deg. F.
With temperatures above 600 deg. there is much danger of
burning the cores. A small core will bake in one hour or
less, but large cores may have to be baked several days and
nights. The amount of heat to use depends for one thing
upon the binder used in the core. Oil binders require more
and quicker heat than flour, resin, or glutrin binders.
Cores should be baked as soon as possible after they are
made, at least the same day or night. If not, they will
partially air-dry, and a poor core will be the result after
baking.
CORE MAKING BENCHES
Small cores are usually made on benches. Any school
can build its own benches, which should be substantial
Fig. 143. — Bench for dry sand core making.
rather than elaborate. However, having a good bench
to work on is frequently a matter of pride with a core
maker.
The bench shown in Fig. 143 is conveniently arranged.
It has a good solid top, and drawers in which to keep tools
and rods. Under the drawers are shelves for the storage
of core boxes.
CHAPTER XV
EXERCISES IN DRY-SAND CORE MAKING
EXERCISE 1. MAKING ROUND CORES
All of the round cores needed in the molding exercises can be
made in core boxes such as shown in Fig. 144. Core mixtures 1
and 2 can be used. A round core is made in the following manner:
Clamp the two halves of the core box together and set the box on
end. Drop a little sand into the box and ram it with an iron rod.
Fig. 144. — Core box and plate with small round cores.
Add a little at a time, and ram, until the box is filled. Punch a vent
hole through the center of the rammed sand.
Remove the clamp and rap the box on all sides. Remove the
half-box that carries the dowel pins and roll the core out of the
other half onto the plate. After the plate is filled put it into the
oven. If necessary, a core of this kind can be reinforced with a rod
before the clamp is taken from the box.
142
EXERCISE 2. MAKING A CONE PULLEY CORE
The core made in this exercise is used in molding the cone pulley,
Exercise 13. Either core-sand mixture No. 1 or No. 2 is suitable.
Figure 145 shows the core and box
To make the core clamp the two half-boxes together and set them
on the small end. Ram the box full of sand. Shck the sand even with
Fig. 145. — Cone pulley core box and core.
Ihe large end. Punch a few vent holes and place a plate of the proper
size over the large end. Then hold the plate and box together firmly
and roll them over. Push into the core, somewhat to one side of
center, a rod, long enough to pass through the part of small diameter
into the main body, leaving it even with the small end. Punch a vent
hold at the center entirely through the core. Remove the clamps and
rap the box. Draw the box from the core as shown in the illustration.
Set the core in the oven to bake.
143
EXERCISE 3. MAKING A CORE FOR A LATHE BED
The core is used in molding the lathe bed, Exercise 17. Use core-
sand mixture 1, 2, or 3. In Fig. 146, A indicates the half core before
it is baked, B the core box, and C the loose strip.
Lay the loose strip of wood into the box in its proper place. Put
a little sand into the box and tuck it under the strip. Fill the box half
full of sand, tucking it into the corners. Place a stiff reinforcing rod
in the middle. Fill the box heaping full of sand and butt-ram, taking
Fig. 146. — Lathe bed core box and core.
care not to ram too hard. Strike off the sand level with the box and
sUck it down even with the top. Cut the vent channels about 3 in.
apart, }/$ in. deep and ^ in. wide. Clamp a plate to the box, make the
roll-over, and rap on all sides. Remove the clamps and draw the box
from the core. The loose strip will not draw out with the box, but must
be drawn out sidewise after the box is drawn. Repair the core if broken,
and plaoe it in the oven to bake. Make a second half-core in the same
way. After the two halves are baked, paste them together and daub
the joints as explained in the sections "Pasting" and "Daubing."
144
EXERCISE 4.
MOLDING THE CORE FOR A MACHINE
BASE
The core is used in molding the machine base, Exercise 18. Use
mixture 3 or 4. Figure 147 shows the box and the half-core. Since
the core is symmetrical, a box for making only half of it is needed.
Fill the box about half full of sand and peen-ram. Put a rod in the
small end, heap the box with sand, and butt-ram. Strike off the sand
level with the top of the box, and shck it with a trowel. Cut the vent
Fig. 147. — Machine base core box and core.
channel beginning it a short distance from the small end and leading it
out of the large end. Punch a few vent holes from the channel to the
sides of the box.
Clamp a plate to the box, make the roll-over, and rap on all sides.
Remove the clamps and draw the box from the core. Make any
necessary repairs and place the core in the oven to bake. Make the
second half. After the two halves are baked, paste them together
and daub the joints.
145
EXERCISE 5.
MAKING A CORE TO BE LIFTED OUT
OF THE PATTERN
The core is similar to the core used in Exercise 19. Use mixture
2 or 3. Use the pattern instead of a core box. As this core must be
hfted out of the pattern, put in two hfting hooks. Figure 148 shows
the pattern and core.
Fill the pattern half full of sand and peen-ram. Set the hooks so
that the eyes are even with the top of the pattern. Ram the pattern
Fig. 148. — Pattern used for core box, and core.
level full of sand and trowel down the surface. Punch some vent holes,
place the plate, make the roll-over, and rap the pattern on all sides.
Draw the pattern from the core and place the core in the oven to bake.
Note. — The core must be set back into the pattern when the mold is
made, and on that account the pattern must be rapped rather hard to
make the core a trifle small. If this is not done, filing will be necessary
to make the core fit the pattern after baking, which causes expansion.
146
EXERCISES IN DRY -SAND CORE MAKING
CORE-MAKING MACHINES
147
Dry-sand core-making machines of which there are
several types, are not used as much as molding machines,
but they are being used more every year. Figure 149
shows a machine for making round cores as long as 24 in.
Fig. 149. — Machine for maldng small round core.
and from % to 3 in. in dia. The ''screw" and ''die" control
the diameter.
In setting up the machine, select die and screw according
to the diameter of core wanted. Attach the screw, F, and
the die, E, in the machine body, A. Run the vent wire, G,
through the screw from the rear end of the machine. Set
the core tray, C, on the machine bed, and the machine is
ready for use.
The two mixtures given below are suitable for use in the
148 FOUNDRY WORK
machine. To operate the machine, mix up a batch of sand
first. Mixture A is for cores ranging in size from % to l^/o
in. in diameter. Mixture B should be used for cores from
11/2 to 3 in. in diameter.
Mixture A Mixture B
8 quarts sharp sand 8 quarts sharp sand
1 quart wheat flour 2 quarts new molding sand
3^ pint core oil 1 quart wheat flour
M pint core oil
Wet the mixture sparingly with water. The mixtures
given must be a little dryer when run through the machine
than if they were used in making cores by hand. If the
sand is too wet, it will pack in the die.
After the sand is mixed, put it into the hopper, B, and
feed it into the machine. Place one hand against the front
of the die and hold it there while turning the wheel, D,
until the sand in the die is packed to the right consistency.
Then remove the hand, but continue to feed sand into the
machine and to turn the wheel. The core will be pushed out
onto the plate. When the length wanted has been made,
cut it off. Before setting the core in the oven to bake,
spray it with water mixed with a little glutrin, to make the
surface firmer.
QUESTIONS
1. What is bench molding?
2. What is floor molding?
3. When should metal patterns be used?
4. Name at least two metals used in gated patterns?
5. Should metal patterns be made when only a few castings are
wanted?
6. What is a follow board?
7. Should a follow board be made for a few castings?
8. What are some of the advantages in using a follow board?
9. What is a match plate?
10. Give some of the reasons for using match plates.
11. Is it a good plan to make match plates for only a few castings?
If your answer is yes, give your reason. If no, why not?
12. Name at least three metals used in making match plates.
EXERCISES IN DRY-SAND CORE MAKING 149
13. What is a squeezer molding machine?
14. For what class of castings are squeezers mostly used?
15. What is a roll-over machine, and how does it operate?
16. W^hat is a stripping-plate machine, and how does it operate?
17. What is a jolter or jarring machine, and how does it operate?
18. What is a combination molding machine?
19. What is a dry-sand core and why are dry-sand cores used?
20. Explain the difference between a dry-sand and a green-sand core.
21. Name some of the essential properties of a good core sand.
22. What are core binders and why are they used?
23. Name at least three core binders.
24. How are dry-sand cores vented?
25. What is vent wax and when and why is it used?
26. What is meant by rodding cores and why is it done?
27. What is meant by pasting and daubing cores?
28. How are dry sand cores treated to make smooth castings?
29. What is an assembled core and how is it assembled?
30. What are lifting hooks and plates and whj' are they used?
31. Why must core plates be used?
32. How does a core binder differ from a core paste?
33. Why are coke and cinders used inside of cores at times?
34. What core binders give off the least gas?
35. At about what temperature should a core be baked?
36. Can cores be baked too much or too little? What will be the
result in either case?
37. If a core is too hard what w411 be the result?
38. How are cores removed from the castings?
39. What fuels are most used for baking cores?
40. Name two types of core ovens.
PART III
MELTING AND MIXING METALS
CHAPTER XVI
FURNACES, GENERAL CONSTRUCTION OF
CUPOLA, TUYERES, CUPOLA LININGS,
AND LINING THE CUPOLA
Melting metals is one of the most important branches of
the foundry business. A careful study of furnaces and
metals is necessary to success in making castings.
Different types of furnaces are used to melt different
kinds of metal. The cupola furnace is used to melt iron
for gray-iron and semi-steel castings. Open-hearth and
air furnaces are used to melt iron for malleable iron, steel,
semi-steel and high grades of gray-iron castings. Crucible,
non-crucible, pit and tilting furnaces are used to melt
metals for steel, brass, bronze and aluminum castings.
Electric furnaces are rapidly coming into use. Some of
the best steels and non-ferrous metals are melted in the
electric furnace. Coke, coal, crude oil, gas and electricity
are used as sources of heat.
The ciopola and crucible furnacesjvvilLbe- tW-©B4y-ones
taken up in detail .
GENERAL CONSTRUCTION OF CUPOLA
A modern cupola furnace is shown in Fig. 150. The
shell, A, is constructed of steel plate from Yiq to % in.
thick. The foundation, B, is made of brick, stone or con-
crete. Columns or legs, C, support the cupola, which with
the windbox, D, rests on the bottom plate, E. There are
two sets of tuyeres, the lower, shown at F, and the upper
shown at G. The bottom doors, H, hang on hinges so that
they can be dropped and raised. All material charged into
the cupola passes through the charging door, /. Melted
metal is run from the cupola through the spout, J, into
153
154
FOUNDRY WORK
ladles. Slag is drawn off through the slag spout, K. The
blast pipe inlet is shown at L, and the blast gage at M.
A section through the safety tuyere is shown at A^ in the
small drawing.
Scc+ion Through
Lower Safei-Li Tuyere
Section Through
IZIZID Wind Box a\ TuijerGs
Fig. 150. — Cupola furnace.
SIZES OF CUPOLAS
Cupolas range in size from 16 to 120 in. in diameter on the
inside of the lining and from 8 to 20 ft. in height from the
FURNACE AND CUPOLA DETAILS 155
bottom plate to the bottom of the charging door. The
total height depends upon the height of the roof of the
building, and varies from 25 to 35 ft. All cupola stacks
should extend out of the building so that the fumes and
gases can be discharged into the atmosphere. The size of
cupola to use depends upon the amount of metal to be run
through during a heat and upon the rapidity with which
the men in the department can take care of the metal.
TUYERES
The openings used to convey air from the wind box into
the cupola are called tuyeres. Tuyeres of many shapes,
forms and sizes have been used, but in modern cupola
practice the tuyere shown in Fig. 151 has proved to be the
best and is generally used. It is flaring in shape and admits
Fig. 151. — A cupola tuyere.
the blast through the small area permitting the air to
spread evenly inside the cupola. The tuyeres are inde-
pendent of each other and on account of their shape are
easily held between the bricks. Most cupolas have a row
of lower and a row of upper tuyeres.
There are usually six tuyeres in a row, separated by
equal distances, with a combined area at the smallest sec-
tion of from 15 to 25 per cent of the cross-sectional area of
the inside of the cupola. They are generally placed from
10 to 30 in. from the bottom plate, the distance depending
upon the amount of metal to be collected in the cupola for
a tap. In some cupolas the tap hole is left open, the metal
running out as fast as it melts, and the tuyeres may be
very near the sand bottom. Other cupolas are tapped at
156 FOUNDRY WORK
intervals and a large amount of metal must be collected
before tapping. In such cases the tuyeres must be well up.
Upper Tuyeres. — Upper tuyeres are similar in construc-
tion to lower tuyeres, and are from 18 to 24 in. above them.
They are to supply air to utilize any escaping gas that may
be used as fuel, and are of great service in quick melting
and in keeping the cupola in blast. Upper tuyeres are
operated independently of lower tuyeres and may be closed
for small heats.
Safety Tuyeres. — The safety tuyere, shown at N, Fig.
150, is a great help in operating a cupola. When the iron
rises too high it will run into the safety tuyere, and thence
down to a hole located under the safety tuyere, in the bot-
tom of the windbox. The hole is covered with cardboard,
which the metal burns, thereby escaping to the ground and
automatically warning the cupola tender that it is time to
tap.
Tuyere Peep Holes. — Hinged frames fitted with mica
are placed opposite the tuyeres. The cupola tender can
look through the mica into the cupola and watch the
operation of the furnace. If the tuyeres become closed the
peep holes can be opened to permit the removal of the
obstruction.
Slag Holes. — A cupola that is to be kept in operation
more than V/o hr. at a time should be provided with a hole
for the removal of slag, which accumulates when the cupola
is in blast. If the slag is not removed, it clogs the cupola
and retards melting. The slag hole is from 2 to 3 in. in
diameter and is usually located in the back of the cupola
opposite the tap hole, from 4 to 5 in. below the lower level
of the tuyeres. When slag holes are too near the tuyeres,
the cold blast chills the slag so that it will not run.
CUPOLA LININGS
Cupolas are lined with either a single or a double course
of fire brick. A single lining is satisfactory in cupolas that
measure less than 36 in. in diameter. Although the first
FURNACE AND CUPOLA DETAILS
157
cost of a double lining is more than that of a single lining,
the double lining is more economical to keep up when used
in cupolas that measure 36 in. and more. In a double
lining, the brick next to the shell need not be of as good
quality as the brick on the inside. Some foundrymen use
common red brick for the shell layer. The advantages of
a double lining are that there is less risk that the lining
will burn through to the shell, and that the inner lining
Fig. 152. — Cupola fire bricks.
can be used more completely than if only a single lining
were employed.
Fire Brick. — Cupola fire brick may be obtained to fit
any size of cupola. Some of the common forms are shown
in Fig. 152. Bricks A, B and C are known as cupola blocks,
A and B for cupolas up to 36 in. in dia. and C for larger
sizes. The wedge-shaped brick, D, is sometimes used as
lining and sometimes as a wedge between cupola blocks.
The square brick, E, is used next to the shell.
158
FOUNDRY WORK
LINING THE CUPOLA
A diagram of the lining in a cupola is shown in Fig. 153.
The single lining is indicated at A, the double lining at B.
The closer the joints can be made the better the lining will
be, because the bricks cut and burn out at the joints more
than at any other place. Once the joints are open, the
gases and blast enter between the bricks, increasing their
Fig. 153. — Diagram of the lining in a cupola.
destruction. A thin grouting, made by mixing fire clay
with water, should be put between the bricks. The mixture
should be so thin that it can be poured on the bricks, or
bricks dipped into it. The bricks should be handled rap-
idly, so that the grouting will not dry before they are in
position, and each brick should be tapped with a hammer
as soon as it is laid, to improve the tightness of the joints.
Fire bricks expand when heated, and to prevent possible
injury to the cupola shell from expansion, they should be
set from y^ to V/U in. from shell. The space between the
shell and the bricks should be filled by pouring in a mixture
of equal parts of clay and sand mixed with water.
FURNACE AND CUPOLA DETAILS 159
Drying the Lining. — After the cupola is lined, it should
be dried slowly. The bottom doors are put up and covered
with a protecting layer of molding sand about 3 or 4 in.
deep. Shavings and kindling are then placed on the sand
and are in turn covered by a layer of coke 20 to 30 in. high.
The fire is lighted and when the coke has caught the drafts
are closed and the coke is allowed to burn out. The bottom
doors are then dropped.
After the bottom has been dropped and the cupola is cool
enough for a man to get inside, the lining should be gone
over with a thin grouting, composed of about V2 pint of
salt to 3 gal. of fire clay, mixed with water until it is so
thin that it can be rubbed into the joints with a brush. The
salt in the mixture will help to glaze the bricks, adding to
the life of the lining. When the first heat is run from a
newly-lined cupola, the fire should be allowed to burn as
long as possible before starting the blast, the blast pressure
should not be stronger than is necessary, and the heat
should be small.
LADLES
Ladles are used to receive the metal from the cupola, in
transporting it, and in pouring it into the molds. They
vary in size and shape, their capacities ranging from 25 lb.
to 100 tons. Bowls for small ladles are made of cast-iron
or sheet iron, and for large ladles, of steel plate. The
shanks, which hold the bowls, are made of wrought iron.
The ladle shown in Fig. 154 is an example of the type
known as hand ladles, which hold from 40 to 80 lb. of
iron and are handled by one man. The shank is indicated
by the letter A, and the bowl by B.
Bull Ladles, as shown in Fig. 155, vary in capacity from
100 to 300 lb. and are usually handled by two men. A
crane ladle is shown in Fig. 156. The capacities of crane
ladles vary from 500 lb. to 25 tons or more. The ladle
shown has a gear controlling device provided to facilitate
pouring.
160
FOUNDRY WORK
Linings. — The linings of ladles vary in material and
thickness, according to sizes. Hand ladles can be lined
with strong molding sand from i/j^ to V^ in. thick. Linings
Fiii. 154. — Hand ladle and shank.
Fig. 155.— Bull ladle and .shank.
Fig. 156.— Crane ladle
for bull and crane ladles must be made of a more refrac-
tory material. A composition of two-thirds fire clay, and
one-third sharp sand, mixed with water, makes a good
material for the linings of ladles that have capacities of
FURNACE AND CUPOLA DETAILS 161
from 100 lb. to 3 tons. The mixture should be just wet
enough that it can be worked easily. Linings for bull and
crane ladles are made from Yo to 2 in. thick, very large
ladles being lined with fire brick.
Before applying the linings, the inside of the bowl should
be wet with a thin clay wash. The lining should be dried
before the ladle is used to prevent the usual bad results
when hot iron is brought into contact with moisture. The
lining can be dried by putting the ladle into the core oven,
or by making a fire inside of the ladle.
BLOWERS AND FANS
There are two types of blowers used to supply air to the
cupola. The one shown in Fig. 157 is shown as a "rotary
Fig. 157. — Rotary positive pressure blower.
positive pressure blower," and the one shown in Fig. 159
is called a fan blower. The rotary positive pressure blower
supplies a constant volume of air to the cupola, but the
fan may not.
In the positive blower, the air intake is usually at the
bottom and the outlet is at the top as shown by the dia-
gram in Fig. 158. The impellers, A and B, do not touch
each other, nor do they touch the case, but they fit so
closely that there is little chance for the air to pass back
when once taken into the blower.
The air intake for the fan is on the sides and the outlet
162
FOUNDRY WORK
is at the bottom. The impellers or blades do not fit closely,
on that account affording opportunity for the air to pass
back.
Diagram of positive pressure blower.
The size of blower or fan to be selected for the cupola
in use can be determined by referring to either cupola or
blower catalogues.
Fig. 159. — A fan blower.
Blowers and fans should be set on solid foundations and
bolted down. They should be placed as near to the cupola
as practicable. The connecting pipes should have as few
fUHNACE AND CUPOLA DETAILS 163
elbows as possible, because elbows retard the pressure of
the blast.
Blast gauges on the cupola to determine the air pressure
may be used successfully, if the tuyeres are kept open.
The pressure to be maintained depends upon the size of the
cupola. For cupolas 24 in. in dia., the pressure should be
from 5 to 7 oz. A 36 in. cupola requires about 10 oz. and
a 48 in. cupola from 12 to 14 oz. Although the blast gage
shows pressure, it does not indicate volume, and if the
tuyeres become clogged, the cupola may not be supplied
with the proper amount of air.
A blast meter is sometimes placed on the main blast
pipe to measure the volume of air passing through. About
30,000 cubic ft. of air are required to melt one ton of iron.
CHAPTER XVII
PREPARING, CHARGING AND OPERATING
THE CUPOLA
Bottom Doors. — When preparing the cupola for a heat,
the bottom doors must be raised and propped as shown at
A, Fig. 160. The prop should rest on an iron plate
embedded in the cupola foundation. Only one prop is
needed for cupolas under 42 in. in diameter, but two are
necessary for cupolas 42 in. or more in diameter. The
props are made of wrought-iron and are from 2 to 5 in.
in diameter. All openings between the doors and the
bottom plate should be filled with clay.
Materials for the Bottom. — The material for the bot-
tom should be of such a nature that it will not wash when
the metal runs over it or when the blast is on. Molding
sand or sand cleaned from gang-ways in the molding room
can be used. The sand should bake a little when the fire
is burning, but must not bake so hard that it will not fall
readily when the doors are dropped. Some foundrymen
wet the sand with a thin clay wash when it is weak.
Putting in the Bottom. — The sand should be as wet as
that used for green-sand molding. After it is mixed, it
should be sifted through a Vo in. riddle. It can be put into
the cupola by being shoveled into the spout and pushed
through the breast opening, or by being taken to the charg-
ing floor and dumped in through the charging door. When
the sand is in, the tender enters the cupola through the
charging door, spreads the sand, rams it and gives it the
proper slope. The sand should be rammed about as hard
as for a mold. Sand that is rammed too hard or too soft
will give the same troubles that it gives in a mold with the
164
PREPARING, CHARGING AND OPERATING 165
additional trouble, in the case of soft ramming, that the
force of the blast may blow the sand out.
Slope of the Bottom. — The sand bottom should be
sloped so that all the metal will run out of the tap hole.
■24
KOHF-^Olbi
%fJGOOLbs.Oo
Floor:
Fig. 160. — Cross section of cupola showing method of lining and charging
A slope of about % to 1% in. to the foot is usually given.
Too steep a slope will cause the metal to run out too
rapidly and will cause undue pressure against the breast
when stopping against a stream of iron. When the slope is
166 FOUNDRY WORK
too gradual, the metal will not run out rapidly enough when
the cupola is drained to drop the bottom.
Kindling. — After the sand bottom is made, some shav-
ings or oiled waste should be put in followed by kindling
large enough to start a coke fire.
Instead of wood, crude oil or gas may be used, with the
advantage that they leave no ash. When oil is used, a
pipe 4 or 5 in. in diameter, with a number of holes 2 in.
in diameter and 3 in. apart, is used to carry the flame. It
should reach from the breast to a point about three-fourths
of the way across the bottom. The oil burner is inserted
through the outer end. After the coke is burning, the pipe
is taken out and put away for the next heat. A similar
piping arrangement is made when gas is used.
Coke Charges. — Every melter must decide how much
coke to put into the cupola for the bed. There is no fast
rule to follow. Common practice is to have it from 20 to
30 in. above the top of the tuyeres after the kindling has
burned out and the coke has settled.
Various methods are used to determine the amount of
coke needed for the bed. Some melters make a mark on
the lining and build the coke up to it after the kindling
has burned. Others measure with a stick from the charg-
ing door. Others compute the amount of coke needed by
finding the volume of the cupola from the sand to the top
of the bed in cubic inches, and dividing by 65, the volume
of one pound of coke (approximately).
Example. — The cupola shown in Fig. 160 is 24 in. in
diameter, measured on the inside of the lining. The distance
from the sand bottom of the tuyeres is 10 in. at the back
and 12 in. at the front, an average height (in the center) of
11 in. The tuyeres are 4 in. high and the coke bed is to be
28 in. above the top of the tuyeres. The total height from
sand bottom is therefore 43 in. (11 + 4+28). The area
(radius squared x tt) of a 24 in. cupola is 452 square
inches (12x12X3.1416). The volume (area of base or
section times height) to be filled with coke is 19,436 cubic
PREPARING, CHARGING AND OPERATING 167
inches (43X452). 19,436^65=299 (say 300) lb. of coke
needed for the bed. About 25 lb. should be held back and
not charged until the other has burned through.
The succeeding layers of coke are usually made from
4 to 10 in. deep. The amounts by weight can be computed
in the same manner as for the bed. A layer 8.5 in. deep
in a cupola 24 in. in diameter weighs approximately 60 lb.
Iron Charges. — The first iron charge is called a Bed
Charge. Its size depends upon the quality of the coke
used, the height of the tuyeres from the sand bottom, and
how hot the metal must be to run the castings. There is
no fast rule to follow. Some melters charge 1 lb. of iron
to 1 lb. of coke, others charge 4 lb. of iron to 1 lb. of coke.
Cupolas which might have the tuyeres placed from 8 to 12
in. above the sand bottom may be charged with 2 lb. of
iron to 1 lb. of coke. At that ratio, the iron charge for the
cupola shown in Fig. 160 would weigh 600 lb.
The iron should be put into the cupola as soon as the
coke bed has burned through, but not before. By delay,
after the bed is ready, heat is lost, and dull iron results.
The size of succeeding iron charges is regulated by the
size of the coke charges. Ordinarily 10 lb. of iron are
charged to 1 lb. of coke. Following that rule, the suc-
ceeding iron charges, in the furnace being dealt with, would
be 600 lb. of iron to 60 lb. of coke.
Lighting Up. — The fire is lighted at the breast and is
allowed to burn through the coke bed slowly to heat up
the cupola. The draft is regulated by means of the tuyere
peep-hole covers. From 1 to 3 hrs. are required for the bed
to burn through, the time depending upon the size of the
cupola and the height of the stack. The bed in a 24-in.
cupola will burn through in about 1 hr. while 1% hr. will be
required in a 36-in. cupola.
Breast. — The large hole in the front of the cupola is
called the breast opening. It is usually left open to give
draft to the fire until the coke bed has burned through.
Then it is closed, as shown at B, in Fig. 160. Closing the
168 FOUNDRY WORK
opening is called ''putting in the breast." The material
used for the breast should be refractory. A mixture of
equal parts of strong molding sand and refractory clay may
be used. This mixture should be wet with water and made
about as damp as the sand used for green-sand molding.
When everything is ready for the breast to be put in, all
loose sand and ashes are brushed out of the hole, and the
sides are wet with clay wash. Short pieces of coke or a
board may be jammed into the opening to form a backing
for the clay. The clay is then put in and rammed against
the coke or board.
Tap Hole. — The tap hole is made when the breast is put
in. A rod from 1 to l^/o in. in diameter is laid in the spout
and on the sand bottom before the breast is put in. After
the breast is rammed, the clay is cut to a funnel shape,
around the rod, and the rod is drawn out, leaving the
tap hole.
Spout. — The spout is lined, as shown at C, in Fig. 160,
with the same clay mixture as used for the breast. The
lining must not be raised above the bottom of the tap hole.
Before starting the blast, the breast and spout linings
must be dried.
Starting the Blast. — After the cupola has been prepared,
the coke bed has burned through, and the first iron charge
is in, the tuyere peep holes are closed and the blast started.
After blowing the air into the cupola from 8 to 12 miri.,
the metal will begin to run out of the tap hole. The first
10 to 25 lb. is too cold to use for pouring, and is allowed
to run into dry sand on the floor. The tap hole is then
closed and the iron accumulated for a tap.
Tapping. — After the metal has accumulated, it is drawn
off at intervals. Tapping a cupola is dangerous work and
must be done carefully.
The tools needed for tapping consist of round iron bars,
from % to IVi in. in dia. and from 3 to 10 ft. long,
pointed, as shown in Fig. 161. There should be from one
to three bars on hand. The clay bott is picked out of the
PREPARING, CHARGING AND OPERATING 169
tap hole carefully. It must not be removed by driving the
bar into it. By driving the bott a sudden rush of iron,
impossible to control, would be caused. The point of the
bar is cooled and hardened by being dipped into water as
soon as the iron is running. In that way it is prepared
for the next tap.
Stopping. — When enough metal has been drawn, the tap
hole is closed with a conical clay bott, stuck on the tip of
a stopping bar such as shown at B, Fig. 161. Stopping is
another dangerous job and the bott must be pushed into the
tap hole without splashing any of the metal. Stopping bars
are iron rods, or they may be made of wrought-iron pipe
1 in. in diameter. In either case the tip is an iron disk,
«
Fig. 161. — Tapping and stopping bar.
securely fastened. From one to three extra bars, with botts
stuck on should always be ready for instant use.
The materials used for the bott should be refractory and
plastic, and of such nature that the bott will bake slightly.
A mixture of seven parts new molding sand, three parts
common yellow clay, one part wheat flour and water serves
the purpose very well. A bott that is too wet will cause
the metal to splash and blow, and one that is too dry will
not stay in the tap hole.
Pouring. — The metal is conveyed from the cupola to the
molding floors in ladles, transported by hand, overhead
trolleys, industrial trucks, or cranes. When pouring molds
the ladles should not be held higher than necessary. The
scum, floating on top of the metal, can be skimmed off with
an iron rod called the skimmer. When pouring, the gates,
170 FOUNDRY WORK
sprue, and pouring basins should be filled quickly and
kept full.
The temperature of the metal should be right before
pouring. Light thin castings must be poured with very
hot metal. Heavy castings should not be poured with
such hot metal, because a large amount will cut the sand.
Hot metal will also cause more shrinkage trouble than dull
metal. It is important that the mold be filled by con-
tinuous pouring. If pouring is stopped too soon, the cast-
ings will be "poured short."
There is usually some metal remaining after the molds
are filled, which is poured into pigs of suitable size, to be
used in later heats. The pigs may be made in sand, or in
cast-iron molds w\ashed with thin clay wash.
Dropping the Bottom. — When enough metal to pour
the molds, or all the metal in the cupola has been melted,
the blast is shut off. After the last tap has been made, all
metal remaining in the cupola is drained out, the tuyere
peep holes are opened, and the bottom doors are dropped
by pulling away the prop. The material that drops out
of the cupola, called the "dump," is spread out and
sprinkled with water to avoid danger of fire and to save
any unconsumed coke.
If the slag that accumulates in front of the tuyeres is
broken off as soon as the bottom is dropped, it is easily
removed and the cupola cools the more quickly.
When the dump is cool enough to be handled, it is
removed. The large pieces of coke and iron are picked out
by hand and the small pieces of iron, coke and slag are
put into a cinder mill where the slag is broken and the
iron freed for reclamation. The reclaimed coke is usually
used for baking cores, but may be mixed with new coke
and used in the cupola. All the iron taken from the dump
is used when making up the charges for later heats.
Chipping the Cupola. — After each heat the slag stick-
ing to the lining must be removed and slag and cinders
hanging over the tuyeres must be chipped off. Due care
PREPARING, CHARGING AND OPERATING
171
must be taken not to break tlie lining. The tools used are
shown in Fig. 162. The cupola tender must be on the inside
of the cupola to do the work. The job is dirty and dusty
and hard on the eyes. Much of the dust can be eliminated
by sprinkling water on the lining and the workman's eyes
should be protected by goggles.
Melting Zone. — The lining in a cupola is usually built
in a straight line from the tuyeres up. After a few heats
it is burned from the top of the tuyeres upward for a
distance of from 2 to 3 ft. It is in this section called the
melting zone, where the temperature is highest, and where
nearly all the metal melts.
Fig. 162.— Cupola picks
The inside diameter of the cupola is increased by the
burning of the lining in the melting zone, but the increase
should never exceed, by more than 4 to 6 in. the diameter
at the tuyeres. The cupola tender secures the best results
by keeping the melting zone in a good condition.
Daubing the Cupola. — The lining must be repaired by
daubing, after each heat, or it will quickly burn out. The
life of the lining depends upon the material used for the
daubing and upon how well the work is done. Some cupola
men are able to use a lining for a long time, while others
have to reline the melting zone quite often.
The material used to daub a cupola should be highly
refractory. Cupola men differ as to the best daubing
172 FOUNDRY WORK
material. A mixture that serves the purpose very well is
composed of two parts fire clay and one part sharp sand.
The fire clay and sand should be mixed dry and then wet
with water. If the daubing is too wet and thin, it does not
stick well, cracks when it dries, and falls off when the
cupola is in blast. Experience will show how thick the
mixture must be and how thick a coat must be applied.
If the mixture is made and put to soak the day before it
is used, it will be better than if mixed just before using.
The lining should be clay-washed before daubing. If
there are large holes burned in the lining, they should be
filled with small pieces of fire brick. The patching can be
done by hand better than with tools.
Breaking-up Molds. — After the molds have been poured,
the loose iron on the tops of the molds should be taken off
with an old shovel and put into a pile to be used again.
The clamps and weights can be removed and the molds
broken up as soon as the metal has solidified. Thin cast-
ings solidify within a few minutes after they are poured,
but the metal in large castings may remain in a fluid state
for hours.
Snap flask molds are much easier to break up than any
other kind. They are simply dumped from the boards.
The boards, and jackets, if used, are returned to the mold-
ing bench.
Some of the larger molds are not so easy to break up,
especially if the copes have bars. The sides of the cope can
be rapped with a hammer or sledge to loosen the sand.
Bars should not be rapped. When the cope is lifted the
casting should remain in the drag. The cope, after the sand
is removed, is placed on the floor with the pins up. The
drag is then rapped, removed from around the casting, and
set on the cope. The casting may be dumped from the
board while hot or left on the board to cool, the procedure
being governed by the size and shape of the casting. Cast-
ings with a tendency toward warping are allowed to cool
on the boards.
PREPARING, CHARGING AND OPERATING
173
Cleaning Castings. — The castings are conveyed from
the molding floors to the cleaning room. The burned sand
is cleaned from them by hand or by machinery. The
sprues, gates, and feeders are broken off by means of
sledge or hammer. The fins and small pieces of the gates
are removed by grinding or chipping. Small- and medium-
sized castings are cleaned and polished in a machine called
a tumbling mill or rattler, as shown in Fig. 163. A rattler
from 20 to 24 in. in dia. and from 24 to 36 in. long
provides a barrel of the proper size for school foundries.
The rattler is filled with castings and small scrap or
"milling stars" and revolved for an hour or two at a rate
Fig. 163. — Tumbling mill or rattler.
of about 75 r, p. m. When taken out, the castings are free
from sand and present a polished appearance.
Thin castings must not be put into the rattler with large
ones, nor must castings be packed too tightly or too loosely.
Tight packing will result in improper cleaning and loose
packing will cause breakage.
Large castings are cleaned by hand or by sand blasting.
In hand cleaning the sand is removed by means of wire
brushes and the castings are rubbed with abrasive stones
or coke.
The cleaning room is usually a dirty and noisy place.
The noise is unavoidable, but much of the dirt and dust can
be eliminated by using either an exhaust or dust collecting
system.
CHAPTER XVIIT
RECORD FORMS
School foundries as well as commercial foundries should
keep accurate records of the work done. The keeping of
records may require extra effort, but the time is well spent,
if the record keeping is not too complicated. Keeping
records and comparing them will help to make the work
more efficient. Every foundryman should know the time
taken for the cupola operations and the blast pressure used.
He should also know the percentage of good castings, the
iron loss in melting, and the melting ratio.
The form shown in Fig. 164 can be used when making up
the charges. The size of the form and the number of
charges can be determined by each foundryman in charge
of the work.
The form shown in Fig. 165 may be used in timing the
operations when taking off the heat and for the blast
pressure.
The summary form in Fig. 166 can be used to keep a
record of the work done. The percentages of good and bad
castings are computed in three ways: On the total metal
charged; on the total number of castings made, or on the
total pounds of castings made. Any one, or all three
methods may be used, depending upon the information
desired.
If the percentage of good castings to the total metal
charged is wanted, the weights of the metal in the follow-
ing groups must be taken into consideration: Good castings;
bad castings; dump; sprues; risers; loss in melting. Their
total weight is taken as 100 per cent. If a check on the
quality of the molds is wanted, the percentage must be
based on the total castings made. The total of good and
174
RECORD FORMS
175
bad castings equals 100 per cent. The pound method of
computing the percentage is preferred to the piece method.
The percentage of good castings that a school can pro-
Weight of Charges in Pounds
Charges
Coke
No. 1 Pig Iron
No. 2 Pig Iron
Scrap Iron
Fhix
1st, or Bed
2nd.
3rd.
4th.
5th.
6th.
7th.
8th.
9th.
Total
Heat No Date Signed
Fig. 164 — Chart for Making up Charges.
duce, computed by the pound method, depends upon the
age of the students, the length of time the students spend
in the course, and the complexity of the work. Students
with no previous foundry training, who are given a course
of from 72 to 100 hr., should obtain an average of about
90 per cent good castings based on total castings made,
if the castings are of the kind treated in this course.
The amount of iron lost during melting depends upon
176
FOUNDRY WORK
how clean and how large the pieces are when charged.
The dirtier the iron and the smaller the pieces, the greater
will be the loss. The average loss in melting is about 8
per cent.
Running Log
Operations
Hours
Minutes
Time of lighting kindling
Time of placing iron bed charge
Time of starting blast
Time of molten metal first appearing
Time of stopping blast
Time of dropping bottom
ounces of blast pressure at
ounces of blast pressure at
Length of heat
Heat No Date Si^
^ned ... .
Fig. 1G5 — Chart for Timing Cupola Operations.
The melting ratio is obtained by dividing the total
amount of iron melted by the total coke burned in melting.
The amount of iron that can be melted with 1 lb. of coke
depends greatly upon the size of the heat and the size of
the cupola. With long heats in large cupolas higher melt-
ing ratios can be obtained than with small heats in small
cupolas.
RECORD FORMS
111
Summary of Heat
Materials
Pounds
Percentages
No. 1 pig iron charged
No. 2 pig iron charged
Scrap iron charged
Total iron charged
Iron recovered from dump
Total iron melted
Good castings made
Bad castings made
Iron in sprues, risers, etc.
Total iron taken from cupola
Iron lost in melting
Fuel
Coke charged
Coke recovered from dump
Coke burnt in melting
Melting ratio (Lbs. of iron melted to 1 lb. of coke)
Heat No Date Signed
Fig. 166 — Chart for Computing Summary of Heat.
CHAPTER XIX
FOUNDRY IRONS
Pig Iron. — The pig iron that the foundryman uses in
making gray-iron castings is a ''blast furnace" product.
It is cast in shapes convenient for cupola melting. The
pigs are cast either in "sand molds" or "pig machines."
The iron is analyzed and graded according to chemical
analysis, and put on the market as Nos. 1, 2, 3, and 4, or
various grades of either northern or southern iron. The
northern irons are mined in the northern part of the United
States, and the southern irons in the southern part.
Pig iron is sold on the long-ton basis, 2,240 lb. The 240
lb. is an allowance made by the blast furnace men to make
up for the sand and slag adhering to the pigs.
Gray foundry irons contain many impurities such as
carbon, silicon, phosphorus, manganese and sulphur. These
impurities will be found in different proportions. If they
were removed, the iron would not be suitable for the manu-
facture of gray-iron castings.
Carbon. — Foundry irons contain from 3 to 4 per cent
of carbon, one of the most important elements in iron. The
condition of the carbon in iron determines its hardness or
softness. Carbon is usually found in two forms, known
to foundrymen as combined and graphitic. When the iron
is in a molten state the carbon is in a combined form. As
the iron solidifies, much of the carbon will pass from the
combined to the graphitic form. The amount of carbon
that changes from the combined to the graphitic form
depends upon the time required for the iron to solidify.
When the carbon is in the graphitic form, the iron is open
grained and soft.
In Fig. 167 is shown a photomicrograph of gray cast
178
FOUNDRY IRONS
179
iron, magnified 100 times. The black portions show the
graphitic carbon and the white portions show the iron and
combined carbon.
Silicon. — Gray cast iron usually contains from 1 to 3.5
per cent of silicon. It is a very important element and is
known as a softener. When the iron is solidifying, the
silicon assists the carbon in changing from the combined
to the graphitic form, and therefore it is a good element to
adopt as a base for general iron mixtures. However, silicon
will cause large castings to be weak and open grained, with
a tendency to leak when subjected to steam, air, or water
pressure.
Fig. 167. — A photomicrograph of gray cast iron. Black shows the graphitic
carbon. White shows the iron and combined carbon. Magnified 100 times.
When small machineable castings are to be made, the
silicon should range from 2.5 to 3 per cent. For large
castings, it should be kept below 2.5 per cent and often
as low as 1 per cent.
Manganese. — INIanganese usually ranges from 0.2 to 1
per cent in foundry irons. It is a beneficial element
because it closes the grain of the iron. Manganese is known
as a st^engthcner. It holds the carbon in a combined state,
without impairing the machining quality, if it is used in
the proper proportion.
A high manganese iron will give soft castings by absorb-
ing sulphur and carrying it in to the slag. For light and
thin castings, the manganese should be kept below 0.5 per
180 FOUNDRY WORK
cent, but for large eastings it is often used in amounts
above 1 per cent.
Phosphorus. — From 0.20 to 2 per cent of phosphorus
is found in gray cast iron. It acts indirectly on the carbon
by its influence in keeping the metal in a molten state,
allowing the carbon to change from the combined to the
graphitic form. An excessive amount of phosphorus in
large castings will cause sponginess and high shrinkage,
and will weaken them, but in small castings, which solidify
quickly, it does not have the weakening effect. Phosphorus
will cause the metal to flow more freely and is therefore
used in amounts as high as 1 per cent in thin castings. It
is usually kept below 0.5 per cent in large castings.
Sulphur. — ^Sulphur is one of the most undesirable ele-
ments in cast iron, and should be kept as low as possible.
Its action is to keep the carbon combined, in a white glazed
state, making the iron very weak, brittle and hard to
machine.
Sulphur exists in the iron as iron sulphide, which melts
at a lower temperature than the iron and remains fluid
longer, so much so that it separates from the iron, causing
blow holes and cracks. It also causes great shrinkage and
dirty castings. Sulphur is absorbed from the fuel when
the iron is melting, and therefore a high sulphur fuel
should never be used. It is a very powerful agent and
causes serious results.
When making up mixtures, the sulphur should never run
higher than 0.1 per cent for large castings. For small
castings, it should be kept below 0.08 per cent if possible.
Scrap Iron. — Pig iron that has been melted in the
cupola, and is to be melted again, is known as scrap iron.
Machinery, stove plate, and car wheel scrap are usually
classed as "cast scrap." Sprues, risers, bad castings and
left-over iron are known as ''scrap." Bought scrap is called
''foreign iron."
The composition of "home" scrap is generally known,
FOUNDRY IRONS 181
but that of foreign scrap is not. It would not be prac-
ticable to try to analyze all scrap. Machinery scrap aver-
ages from 2 to 2.5 per cent silicon, 0.5 to 0.7 per cent
manganese, 0.5 to 0.7 per cent phosphorus, and 0.05 to 0.15
per cent sulphur.
Remelting Iron. — Iron usually becomes harder each
time it is remelted, due to a decrease in the elements that
soften the iron and an increase in the elements that harden
it. There is not much change in the total amount of carbon
in the iron when it is melted in the cupola, but there is an
increase in the percentage of combined carbon.
The loss of silicon averages about one-tenth of the amount
present each time the iron is melted and that amount of
loss should be used in computing mixtures.
In the same way the loss of manganese is about one-fifth.
It is not necessary to make any allowance for phosphorous
because the amount of that element remains practically
constant.
The gain in sulphur depends upon the quality of the coke,
usually being equal to about 4 per cent of the sulphur in
the coke. The increase depends somewhat upon the amount
of manganese in the iron and how the cupola is fluxed.
Manganese usually absorbs some of the sulphur and carries
it into the slag.
MIXING IRONS BY FRACTURE AND CHEMICAL
ANALYSIS
When making up mixtures of different pig irons and
scrap irons the class of casting to be made and the kind
of iron on hand must be considered. Castings that are to
be machined must be soft. Those that do not need to be
machined may be either soft or hard. Some castings must
be strong and close grained while others may be weak and
open grained, depending upon the use to which they are
to be put.
It is wise to use a soft pig iron in school foundries, one
182
FOUNDRY JVORK
that will carry at least 50 per cent of scrap, because stu-
dents are certain to make scrap.
Fracture Mixing. — An iron that has a very open,
coarse grain with a silvery gray color is weak and soft.
As the grain becomes finer and the color lighter, the iron
becomes harder and stronger. The quality of an iron can
be judged by the texture and color of the fracture. When
the fracture has a white color and a very fine and dense
grain, the iron is usually hard, but weak. A fairly good
mixture may be made by studying the fracture of irons,
but mixing by analysis is the more accurate method.
Mixing by Analysis. — The analyses of pig irons can
be obtained from the manufacturers. For ordinary cast-
ings such analyses are accurate enough, but many foundries
have their own chemical laboratories and analyze the iron
before making up mixtures.
In the following a concrete example will be taken up to
compute a mixture suitable for small castings that are to
be machined. The charges will fit the cupola shown in
Fig. 160. The mixture will carry 50 per cent of scrap.
Suppose that three grades of iron are at hand, two of
pig and one of scrap, and they analyze as follows:
Silicon
Manganese .
Phosphorus
Sulphur. . . .
No. 1 Pig Iron
3.5
0.6
O.S
0.03
No. 2 Pig Iron
%
3.
O.S
0.6
0.04
Scrap Iron
%
2.25
.6
.7
.08
The castings to be made are to have the following
analysis: Silicon, from 2.50 to 2.75%; manganese, between
0.5 and 0.7%; phosphorus, between 0.60 and 0.80%.; sul-
phur, not over 0.10%o.
FOUNDRY IRONS
183
Silicon
200 lb. of No. 1 pig iron
contain 7.00 lb. of silicon
100 lb. of No. 2 pig iron
contain 3.00 lb. of silicon
300 lb. of scrap iron
contain 6.75 lb. of sihcon
600 lb. of the mixture
contain 16.75 lb. of silicon
100 lb. of the mixture
contain 2.79 lb. of silicon
Loss in melting (Ko of the above)
0.28 lb. of sihcon
Remaining in castings made from 100 lb. of mixture 2.51 lb. of silicon
The percentage of silicon is therefore 2.51,
Manganese
200 lb. of No. 1 pig iron
contain 1.2 lb. of manganese
100 lb. of No. 2 pig iron
contain 0.8 lb. of manganese
300 lb. of scrap iron
contain 1.8 lb. of manganese
600 lb. of the mixture
contain 3.8 lb. of manganese
100 lb. of the mixture
contain 0.633 lb. of manganese
Loss in melting (3^^ of the above)
0.127 lb. of manganese
Remaining in castings made from 100 lb. of mixture
0.506 lb. of manganese
The percentage of manganese is therefore 0.506, say 0.51
200 lb. of No. 1 pig iron
100 lb. of No. 2 pig iron
300 lb. of scrap iron
600 lb. of the mixture
100 lb. of the mixture
Phosphorus
contain 1.60 lb. of phosphorus
contain 0.60 lb. of phosphorus
contain 2.10 lb. of phosphorus
contain 4.30 lb. of phosphorus
contain 0.72 lb. of phosphorus
The percentage of phosphorus is therefore 0.72
Sulphur
200 lb. of No. 1 pig iron
100 lb. of No. 2 pig iron
300 lb. of scrap iron
600 lb. of the mixture
100 lb. of the mixture
Gain in melting (4 per cent of sulphur
in coke, assuming a coke contain-
ing .75 per cent sulphur)
Existing in castings made from
100 lb. of mixture
contain 0.06 lb. of sulphur
contain 0.04 lb. of sulphur
contain 0.24 lb. of sulphur
contain 0.34 lb. of sulphur
contain 0.057 lb. of sulphur
0.03 lb. of sulphur.
0.087 lb. of sulphiu-
The percentage of sulphur is therefore 0.087, say 0.09
GENERAL PURPOSE MIXTURES
Light Castings. — When the metal is not more than i/o
in. thick in any section, castings are known as light cast-
184 FOUNDRY WORK
ings. A mixture suitable for light castings is: Silicon 2.50
to 2.75, manganese 0.40 to 0.70, phosphorus 0.60 to 0.8,
sulphur not over 0.08.
Medium Castings. — Castings that have sections thicker
than Yz in. and up to 2 in. thick are called medium castings.
A mixture suitable for medium castings is: Silicon 1.75 to
2.00, manganese 0.60 to 1.00, phosphorus 0.40 to 0.60,
sulphur not over 0.10.
Heavy Castings. — Any castings having no section less
than 2 in. thick are called heavy castings. A mixture
suitable for heavy castings is: Silicon 1.00 to 1.50, man-
ganese 0.70 to 1.00, phosphorus 0.20 to 0.50, sulphur not
over 0.12.
TESTING GRAY CAST IRON
The main tests to which gray cast iron is subjected are
those for transverse strength, flexure, shrinkage, chill and
hardness.
Testing Machines. — There are many types of testing
machines that have capacities from 50,000 to 100,000 lb.
Small shops and school foundries usually have small test-
ing machines which they operate by hand.
Test Bars. — The bars used in making the transverse-
strength test may be either round or square, ranging in
size from i/o to P^ in. in diameter or V^ to IVo in. square.
The bar that is as nearly standard as any is I14 in. in
diameter and 15 in. long. It is known as the Arbitration
Test Bar.
The transverse-strength test is made by placing the bar
on knife edges 12 in. apart and applying the load in the
center until the bar breaks. To find the transverse strength
of the bar in pounds per square inch, the breaking load in
pounds is divided by the area of the bar in square inches.
For example, the area of the arbitration bar is 0.625 X
0.625X3.1416- 1.225 sq. in. If the bar breaks at 3,500
lb., the transverse strength is 3,500-^ 1.225=2,857 lb. per
square inch.
FOUNDRY IRONS
185
There is great variation in the strength of gray cast iron,
due to its composition. The transverse strength per square
inch of any cast iron should not be under:
For light castings, 2,100 lb.
For medium castings, 2,400 lb.
For heavy castings, 2,700 lb.
Iron of some compositions and grades will have greater
transverse strength, sometimes as high as 3,500 lb.
Flexure Test. — The flexure test, usually conducted in
connection with the transverse test, shows how much the
iron will bend before it breaks, an indication of whether
or not it is suitable for castings that have to withstand
many jars and shocks. A bar 1^/4 in. in diameter with 12
K-
/4i
— >i
CI amp
<
—
3or 1
<
„f A
Fig. 168. — Shrinkage clamp and bar.
in. between supports, should bend at least 0.1 in. before
breaking, and in many cases the deflection will be as much
as 0.15 in.
Shrinkage. — For some castings, such as pulleys and
gears, it is important to know the rate of contraction of the
iron. In gray cast iron it ranges from %o to % in, to the
foot. The average is usually given at % in.
When making the test bar to be used in measuring con-
traction, a pattern 12 in. long and 1 in. square may be
used. A good and simple way to mold the bar is to lay
the pattern in a clamp as shown in Fig. 168, and build the
mold around it. The inside dimension of the clamp is
12 in. When a clamp is used there is no danger that the
mold will be longer than 12 in., due to rapping the pattern.
186 FOUNDRY WORK
After the bar has been poured and is cool, it is measured
and the contraction noted.
Hardness Test. — To test the castings for hardness either
a sample casting or a test bar can be used. The pieces of
the bar in the transverse test will do very well. The hard-
ness is determined by drilling holes in the iron and observ-
ing the speed of cutting, or by filing it. Either test can be
made very accurately after a little practice.
There are two tests for hardness that are made with
special testing machines. They are known as the Brinell
test and the Scleroscope test.
CHAPTER XX
NON-FERROUS METAL FOUNDING
The making of molds for brass and aluminum castings
is similar to the making of molds for iron castings. Any
one who understands making molds for iron castings can
soon learn to make molds for brass castings. The molding
exercises given in the book can be poured in brass as well
as iron.
Light brass and aluminum castings should be very
smooth, a fact that necessitates the use of a fine-grained
sand. The tendency of molten brass is to eat into the
sand, thereby causing the castings to be rough and streaky.
Care in selecting a sand from among the several grades
and kinds in the market will pay.
In foundries where only a few brass castings are made,
and fully equipping for them would not be justified, fairly
good castings can be made 'by using the regular molding
sand and facing the pattern with a fine-grained sand to a
depth of about V^, inch.
Another way to secure a comparatively smooth surface
is with cement, which is dusted on from a bag after the
"pattern is drawn. Then the pattern is ''printed back" (see
Chap. IV). The pattern must not remain in the sand
more than a minute or so, because the cement becomes
damp and will stick to it.
The sand for non-ferrous casting must be kept free of
all^Weign matter and any material that will cause it to
become qparse. Such small pieces as burned dry-sand core
and nails should be carefully picked out.
Parting Material. — Common parting sand is seldom
used in brass molding, because it is too coarse. There are
on the market many commercial parting compounds that
187
188
FOUNDRY WORK
ran be used without harming the sand. One of the best
materials is lycopodium, to which the only objection is
its high price. The parting compounds, or the lycopodium,
should be dusted onto pattern and mold from bags.
Furnaces. — Furnaces used to melt non-ferrous metals, of
which there are many types, range from the coke-fired,
crucible pit furnace to the electric furnace. In some foun-
dries the metal is melted in crucibles, and in others in the
hearth of the furnace.
The crucible pit furnace is probably the cheapest to
install and is the furnace most used by school foundries.
Fig. 169. — Cruoible pit furnace.
For those reasons it has been selected for treatment in this
course. Its construction is shown in Fig. 169. The shell, A,
is made of steel plate %c i^- thick. It rests on plate, B,
made of cast iron. The legs, C, support the furnace high
enough from the floor to allow for draft and ashes. The
grate, D, works on hinges so that it can be raised and
dropped. It is turned by the handle, G. The cover, E,
holds down the flame. The furnace should be connected
by the flue, F, with a chimney.
Crucible pit furnaces are built in sizes ranging from 23
to 36 in. in diameter and from 24 to 36 in. high. Their
NON-FERROUS METAL FOUNDING 189
melting capacities are from 20 to 200 II). of brass or from 10
to 70 lb. of aluminum per heat. Linings are made of fire
brick as in the cupola furnace. Sometimes the furnace is
set on the floor, but it is much more easily operated when
set in a pit as shown in Fig. 172.
Crucibles. — The crucibles, shown in Fig. 170, are made
of graphite and a special clay, known as German clay. They
are made in standard sizes and are numbered from 1 to
400. To find the amount that a crucible will hold, multiply
its number by three for brass, and by one for aluminum.
For example, No. 20 crucible has a capacity of 60 lb. of
brass or 20 lb. of aluminum. The No. 20 is the best size
to use in the furnace shown in Fig. 172.
Fig. 170. — Crucibles.
Care of Crucibles. — A new crucible should be annealed
and then heated up gradually to about 600 deg. F. before
the first heat is taken. Heating up a new crucible too
rapidly will cause it to crack or flake off (known as
"scalping"). Crucibles must be kept in a warm place
free from moisture. The shank and tongs must fit properly,
and when the crucible is removed from the furnace, it
should never be placed in wet sand.
A few ''don'ts" to be observed in the care of crucibles are:
Don't put a damp crucible into a hot furnace.
Don't use wet coke to melt metals.
Don't wedge the metal into a crucible.
Don't leave the crucible in the fire after the metal
is ready to pour.
Don't leave the metal in the crucible to cool.
190
FOUNDRY WORK
Don't drop cold metal into the crucible from a
distance.
Don't set hot crucibles in cold drafts, or near an
open door during the winter.
Tongs. — In Fig. 171 three tongs are shown: A, the cru-
cible tong, used to lift the crucible from the furnace; B,
the pick-out tong, used to pick the coke from around the
crucible to make possible getting a firm hold with the
crucible tongs; and C, the shake-out tong, used to shake
the castings out of the sand after the molds are broken up.
Fig. 171. — Crucible, pick out and shake out tongs.
Operating the Furnace. — To operate the furnace shown
in Fig. 172: Place shavings and kindling on the grate, and
about 50 lb. of coke on the kindling. Light the shavings.
After the coke is well lighted, build up the coke bed so that
the top of the crucible, A, when put on, will be even with
the top of the flue, B. Place the metal in the crucible and
the crucible on the coke bed. Fill in around the crucible
with small pieces of coke up to the level of the top of the
crucible. These pieces of coke should not be larger than
hen eggs. Close the cover.
No further attention need be paid to the furnace for
about an hour except to see that the fire is burning. From
NON-FERROUS METAL FOUNDING
191
1 to 2 lir. are required for the furnace to become hot
enough to melt any of the metal, especially brass.
It sometimes happens that the coke burns out around the
crucible before the metal is melted or hot enough to pour.
In such a case the crucible must be raised and new coke
put around it. To lessen the tendency of the crucible to
sink to the grate, it is a good plan to put a brick, C, about
4 in. thick, on the grate before charging the furnace.
Y////7.
s
J
^
JM v\^vvv\m\iy///Z
z_
Fig. 172. — Cross-section of crucible furnace.
As soon as the metal is hot enough to run the castings,
the crucible should be taken from the furnace, and set into
the shank, and the metal poured.
If only one heat is to be taken out of the furnace in a
day, the coke should be dumped and the crucible put in
a warm place to cool. If more than one heat is to be run,
more coke should be put on the bed, the crucible recharged
and set into the furnace, and more coke placed around it.
A heat from a cold furnace requires from 3 to 4 hr.
Following heats can be taken in from 1 to 3 hr. When
preparing the furnace for the second and following heats,
192
FOUNDRY WORK
all ashes and unburned coke should be removed from under
the grate and any unburned coke should be used again.
ALLOYING NON-FERROUS METALS
The metals most frequently used to make non-ferrous
metal castings are copper, tin, zinc, lead and aluminum.
These five metals may be mixed in varying proportions to
form many alloys, chief among them "red brass," "yellow
brass," "bronze," "bearing metals" and alloys of aluminum.
When alloying, the metal with the highest melting point
should be melted first, then the one with the next highest
melting point, and so on until all of the metals that are to
make up the alloy are melted together. For example, in
making a red brass alloy, the copper is melted first, then
the zinc, then the lead, and last the tin. As soon as the
mixture is hot enough to run the castings, it should be
taken out of the furnace, or the zinc, tin and lead may
burn away.
Red brass is usually a mixture of copper, tin, zinc
and lead. The proportions of the metals are not always
the same. Two mixtures often used are as follows:
RED BRASS
Mixture 1
Mixture 2
Copper
Tin
Zinc
Lead
85 per cent
5 per cent
5 per cent
5 per cent
Copper
Tin'
Zinc
Lead
Red brass scrap
60 per cent
4 per cent
4 per cent
2 per cent
30 per cent
Yellow brass is usually a mixture of copper and
zinc, although many of the yellow brass alloys contain a
small percentage of tin and lead. The followmg are typical
yellow-brass mixtures:
NON-FERROUS METAL FOUNDING
YELLOW BRASS
193
Mixture 1
Mixture 2
Copper
Zinc
70 per cent
30 per cent
Copper
Zinc
Tin
Lead
73 per cent
23 per cent
2 per cent
2 per cent
There are many alloys called bronze. The most common
ones are known as '^straight bronze," '^phosphor bronze"
and "manganese bronze."
Straight bronze is usually a mixture of copper and tin,
but there are many bronzes that contain zinc and lead,
especially the cheaper mixtures. The following mixtures
are known as straight bronze:
BRONZE
Mixture 1
Mixture 2
Copper
Tin
90 per cent
10 per cent
Copper
89 per cent
Tin
8 per cent
Zinc
1 . 5 per cent
Lead
1 . 5 per cent
Phosphor bronze castings may be made by adding a lit-
tle phosphorus to the mixture. If phosphor-tin is used,
and alloyed with the copper, better results will be obtained
than if the phosphorus is mixed with the copper. The
following mixtures are called phosphor bronze:
PHOSPHOR BRONZE
Mixture 1
Copper
Phosphor tin
90 per cent
10 per cent
Mixture 2
Copper
Phosphor tin
Zinc
Lead
Scrap phosphor
bronze
65 per cent
5 per cent
2 per cent
3 per cent
25 per cent
194
FOUNDRY WORK
Manganese bronze alloys are usually made by using
both copper that contains from 5 to 15 per cent of man-
ganese, and copper that contains no manganese. The fol-
lowing mixtures make typical manganest bronze:
MANGANESE BRONZE
Mixture 1
Mixture 2
Copper that con-
3 per cent
Copper that con-
8 per cent
tains 15 per
tains 5 per cent
cent of manga-
manganese
nese
Copper that con-
58 per cent
Copper that con-
51 per cent
tains no man-
tains no man-
ganese
ganese
Zinc
38 per cent
Zinc
40 per cent
Aluminum
1 per cent
Aluminum
1 per cent
Bearing Metals are made according to formulas,
following are two typical mixtures:
The
BEARING METAL
Mixture 1
Mixture 2
Copper
76 per cent
Copper
38 per cent
Tin
8 per cent
Tin
4.5 per cent
Lead
15 per cent
Lead
7.5 per cent
Phosphorus-
1 per cent
Scrap bearing
50 per cent
copper
metal
For metal pattern and match plate mixtures, the fol-
lowing formulas mav be used:
METAL PATTERNS
Mixture 1
Copper
Aluminum
8 per cent
92 per cent
Mixture 2
Antimony
10 per cent
Zinc
5 per cent
Tin
25 per cent
Lead
60 per cent
NON-FERROUS METAL FOUNDING 195
Aluminum alloys are used extensively for castings that
are to be light in weight, because pure aluminum is too
soft. Usually the aluminum predominates. To obtain a
well-mixed alloy, it is necessary to make a primary alloy
known as a hardener which ordinarily contains 50 per cent
of aluminum and 50 per cent of copper or zinc. The hard-
ener is cast into pigs suitable for handling. When the alloy
for the casting is to be made, a certain percentage of the
hardener is mixed with the pure aluminum. For example,
in making the mixture known as No. 12 aluminum alloy,
which contains 8 per cent of copper, 84 per cent of pure
aluminum and 16 per cent of the hardener are used.
QUESTIONS
1. Name three types of furnaces used for melting metals.
2. Why are cupolas lined, and how?
3. After cupolas are lined how should the lining be treated before
taking off the first heat?
4. Why are tuyeres used in a cupola?
5. What is a slag hole, what is its object, and how should it be
located?
6. What materials are used for making the sand bottom?
7. What is meant by the melting zone of a cupola? Where is it
located in relation to the tuyeres?
8. What is meant by the bed in a cupola?
9. How is the amount of coke for the bed determined?
10. If the iron charges are too heavy for the coke charges, what will
be the effect on the iron?
11. Should the fire in a cupola be started before or after charging the
iron, and why?
12. If too little fuel is put between charges of iron what will be the
result?
13. How must a cupola be taken care of after a heat has been taken?
14. Describe one method of making breast and tap hole for a cupola.
15. What two classes of machines are most commonly used for pro-
ducing the blast for a cupola, and in what respect do thej^ differ?
16. Name the two kinds of coke used to melt iron in a cupola.
17. What materials are used to line ladles, and why are they lined?
18. What will be the result if the ladle linings are not dry?
19. If the metal is poured too cold what will be the result?
20. How are the molds broken up after they are poured?
21. How are the castings cleaned?
22. What is meant by the melting ratio and how is it computed?
196 FOUNDRY WORK
23. What is meant by the loss in melting and how is it computed?
24. Describe a safety tuyere and safety drain, and explain their use.
25. How many pounds of iron will a pound of coke melt in a cupola?
26. How thick should the charges of coke be between the charges of
iron?
27. What is gray cast iron and how does it differ from pure iron?
28. Name the "big five" impurities in gray cast iron.
29. What effect has carbon on gray cast iron, and in what form is it
found in the iron?
30. Which of the impurities make gray cast iron harder?
31. Which of the impurities make gray cast iron softer?
32. What effect has remelting on cast iron? Does it make it harder
or softer?
33. What effect has the chilling of iron on the casting?
34. What are the important tests usually used on gray iron castings?
35. What is meant by the ''arbitration test bar"?
36. What kind of molding sand is used in making brass castings?
37. What types of furnaces are used to melt non-ferrous metals?
38. What care should be used in handling crucibles ?
39. What is brass? Give a mixture.
40. What is bronze? Give a mixture.
TABLE L— MELTING POINT, SPECIFIC GRAVITY,
WEIGHT AND TENSILE STRENGTH OF METALS
Name
Aluminum
Aluminum bronze. .
Brass (common) . . .
Bronze
Copper
Gray cast iron
Lead
Malleable iron
Manganese bronze. .
Phosphor bronze . . .
Cast steel
Tin
Zinc
Melting
Point
Specific
Deg. F.
Gravity
1,300
2.6
1,700
7.56
1,800
8.3
1,900
8.4
2,000
8.6
2,200
7.2
620
11.3
2,100
7.2
2,000
8.4
2,000
8.4
2,800
7.9
512
7.3
775
6.86
Wt. per
1
Wt. per
Cu. In.
Cu. Ft.
in Lb.
in Lb.
0.089
162
0.28
485
0.31
539
0.31.5
545
0.31.8
550
0.26
450
0.41
712
0.20
450
0.3
525
0.3
525
0.28
485
0.26
460
0.25
455
Tensile
Strength
Lb. per
Sq. In.
23,000
80,000
24,000
32,000
24,000
20,000
1,800
64,000
57,000
40,000
70,000
4,600
2,900
TABLE XL— SHRINKAGE OF CASTINGS
In. per Ft.
In. per Ft.
Bismuth
5/32
3/16
3/16
1/10
Tin castings
Lead
Zinc
1/4
Brass castings
Copper castings
Gray iron castings ....
5/16
5/16
TABLE III.— CUBIC FEET TO A TON OF EARTH
Cu. Ft.
Cu. Ft.
Sand, river (loaded in
wagon)
Sand, pit (loaded in
wagon)
21
22
Gravel, coarse (loaded
in wagon)
Clay, stiff (loaded in
wagon)
23
28
One cubic yard of sand weighs about 3,000 lb.
197
FOUNDRY BOOKS FOR GENERAL READING
Belt, Robert E., "Foundry Cost Accounting." Pcnton Publishing
Co., Cleveland, O.
Buchanan, John F., "Practical Alloying." Penton Publishing Co.,
Cleveland, O.
Carman, Edwin S., "Foundry Molding Machines." Penton Publishing
Co., Cleveland, O.
Hall, John Howe, "The Steel Foundry." McGraw-Hill Book Co.,
New York, N. Y.
Kirk, Edward, "The Cupola Furnace." Henry Carey Baird & Co.,
New York, N. Y.
MoLDENKE, Richard, "The Production of Malleable Castings."
Penton Publishing Co., Cleveland, O.
MoLDENKE, Richard, "The Principles of Iron Founding." McGraw-
Hill Book Co., New York, N. Y.
Palmer, R. H., "Foundry Practice." John Wiley & Sons, New York,
N. Y.
Payne, David W., "Founder's Manual." D. Van Nostrand Co.,
New York, N. Y.
West, Thomas D., "American Foundry Practice." John Wiley &
Sons, New York, N. Y.
West, Thomas D., "Moulder's Text Book." John Wiley & Sons,
New York, N. Y.
198
GLOSSARY OF FOUNDRY TERMS
Air-dried
Alloys
Anchor
Annealing
Bed charge
Bedding-in
Bench molding
Binder
Blast
Blow hole
Bott
Bottom board
Breast
Butt-ramming
Bull ladle
Casting
Chaplet
Cheek
Chill
Chilled casting
Churning
Cinder bed
Clay wash
Clamping iron
Cold shut
Refers to a core that has dried or partially dried in
the a'r before baking.
A combination of metals melted together.
Appliance used to hold cores in place in molds.
Softening, by heat.
The first charge of coke put into the cupola.
Sinking a pattern into the sand.
Making molds on a bench.
Material used to hold sand together,
A current of air blown into the cupola by blower
or fan.
Hole in the casting caused by trapped air or gas.
The chunk of clay stuck on the end of a stopping
bar, and used to stop the flow of metal from
the cupola.
The board that the mold rests on.
The clay put into the opening, above the spout, to
form the tap hole.
Ramming with flat end of the rammer.
A two-man ladle used for carrying metal.
The iron, brass, or alloy article, or part, that is
obtained as a result of pouring metal into the
molds.
A metal support used to hold a core in place.
The middle part of a three-part flask.
Iron placed against a pattern when making a
mold.
A casting that was cooled very rapidly.
Feeding metal into a casting with an iron rod,
through the feeder or riser.
A layer of cinders placed beneath a mold. Gas,
from the mold, escapes through the cinders and
is led out through pipes.
Clay, thinned with water, and used as a coating
for gaggers and flasks.
An iron bar used to tighten clamps on flasks.
The junction where two streams of metal run
together and do not fuse.
199
200
FOUNDRY WORK
Contraction Decrease in volume due to cooling.
Cope The upper part of a flask or mold.
Core A body of sand used to form holes or openings
through castings.
Core box A box in which a core is formed.
Core oven An oven in which cores are baked.
Core plate An iron plate on which a core is baked.
Core driers A form which holds the core in shape while it is
baking.
Core print A projection on a pattern which forms in the sand
an impression used in locating a core and in
holding it in place.
Core wash A blackening mixture with which cores are
painted.
Crushing The pushing out of shape of core or mold, when
two parts of the mold that do not fit properly
meet.
Daubing Filhng cracks in cores or plastering a cupola after
heat.
Draft The taper on a pattern that makes drawing it from
the sand possible.
Drag The bottom part of a flask or mold.
Draw plate A plate put into a pattern to be used for drawing
the pattern.
Drop-out The falling-away of part of a mold.
Dull iron Iron not as hot as it should be for best pouring.
Facing A material put next to the pattern when making
the mold.
Feeding Pouring metal into the feeder while the casting is
solidifying.
Fin Metal that has run into an imperfect joint in the
mold.
Flow-oflf gate. An opening through which the metal flows after
the mold is filled.
Floor molding Making molds on the foundry floor.
Flux A material charged into the cupola to thin the
slag.
Follow board A board in which the pattern lies to the parting
line.
Gaggers Metal support used to reinforce the sand in the
cope.
Green sand Sand that is in a damp state.
Green core A core that is not baked.
Green ladle A ladle with a lining that is not dry.
Hand ladle A small ladle carried by one man.
GLOSSARY OF FOUNDRY TERMS
201
Hot metal
Loam
Melting zone
Match plates
Molding board
New sand
Old sand
Patching
Peeling
Peen-ramming
Pit molding
Rapping
Scabbed castings
Scrap iron
Sea coal
Skimmer
Skimming
Skin drying
Slag
Soldiers
Spongy castings
Spout
Swab
Sweep work
Tuyere
Weak sand
Metal hot enough to flow easily.
A mixture of sand and clay used in loam molding.
The portion of the cupola above the tuyeres, where
the metal melts.
A plate to which the pattern is fastened at the
parting line.
The board on which the pattern is placed when
beginning to make the mold.
Sand that has not been used for molding.
Sand in which castings have been poured.
Repairing broken parts of the mold.
The ready dropping away of sand from the cast-
ing.
Ramming with the wedge end of the rammer.
Making molds in pits in the foundry floor.
Striking the pattern to loosen it in the sand.
Castings having rough surfaces.
Metal to be remelted.
Soft coal, finely ground.
A piece of iron used to prevent the dirt from flow-
ing into the mold when pouring a casting.
Holding back the dirt on the iron when pouring.
Drying only the face of the mold.
Impurities fluxed from the cupola.
Wooden blocks used to reinforce sand when mold-
ing.
Castings in which the iron is very open-grained.
A trough through which the metal flows from the
cupola to the ladle.
A sponge or piece of waste used to wet the sand
around the pattern before drawing it from the
sand.
Making molds with sweeps instead of patterns.
An opening through which the air passes from the
wind box into the cupola.
Sand that will not hold together.
INDEX
Alloying non-ferrous metah
Aluminum alloys, 195
Baking cores. 139, 140, 141
Bench molding benches, 55,
Blast furnaces,
charging of, 5
linings for, 6
size of, 5
Blast gauge, 163
Blast meter, 163
Blowers, 161
Blower diagram, 162
Blow holes, 16, 17
Books for general reading,
Breaking gates and feeders
castings, 38, 39
Breaking up molds, 172
Brass and bronze mixtures,
bearing metals, 194
bronze, 193
manganese bronze, 194
pattern metal, 194
phosphor bronze, 193
red brass, 192
yellow brass, 193
192
56
198
from
Carbon, 178, 179
Chaplets,
kind of, 43
setting of, 44, 45
wedging on, 46
Chipping cupolas, 170, 171
Clamps, 26
Cleaning castings, 173
Commercial foundry outlay,
cleaning room, 10
coremaking room, 9
cupola room, 8
pattern storage room, 8
Construction of cupola, 153, 154
Cokes,
bee-hive, 3, 4
by-product, 3, 4
Coremaking bench, 141
machine, 147, 148
Core ovens, 139 to 140
Crucibles, 189
care of, 189, 190
Cupola operations,
blast starting, 168
bottom doors, 164
bottom door material, 164
breast making of, 167, 168
coke charges, 166
dropping bottom, 170
iron charges, 167
kindling, 166
hghting up, 167
picks, 171
putting in bottom, 164
sizes, 154, 155
sloping of bottom, 165
spout making, 168
stopping cupola, 169
tap holes, 168
tapping, 168, 169
Cupolas, hnings, 156, 157
Daubing cores, 138, 139
cupolas, 171, 172
203
204
INDEX
Drying cupola linings, 159
Dry sand cores,
arbor for, 137
binders for, 134
compositions of, 132
lifting hooks for, 138
mixtures for, 133
paints for, 134
plates for, 135
ramming for, 135
rodding, 137
venting, 136, 137
wax tapers for, 136
Exercises in bench molding,
No. 1 face plate, 57, 58, 59, 60
No. 2 hexagonal nut, 61, 62
No. 3 ball handle, 63, 64
No. 4 oil drip cup, 65, 66
No. 5 split pattern. 67, 68
No. 6 A pulley, 69, 70
No. 7 governor pulley, 71, 72, 73
No. 8 sheave wheel, 74, 75
No. 9 bevel gear, 76
No. 10 face plate imbedded, 77
No. 11 thinning a plate, 78, 79
No. 12 making a pulley longer
than pattern, 80, 81
Exercises in dry sand core-
making,
No. 1 round core, 142
No. 2 cone pulley, 143
No. 3 lathe bed, 144
No. 4 machine base, 145
No. 5 core to be lifted out of
pattern, 146
Exercises in floor molding,
No. 13 cone pulley, 83, 84, 85
No. 14 gas engine fly wheel,
86, 87
No. 15 sugar kettle, 88, 89
No. 16 steam engine piston,
90, 91
Exercises in floor molding.
No. 17 lathe bed, 92, 93
No. 18 machine base, 94, 95, 96
No. 19 lifting dry sand core
out of pattern, 97
No. 20 making plate in open
sand, 98, 99
No. 21 sweep molding, 100, 101
No. 22 pit molding, 102, 103
Exercises in foundry problems,
No. 1 foundry layout, 105
No. 2 cupola practice, 106
No. 3 computing weights, 107,
108
No. 4 computing mixtures, 109,
110, 111, 112, 113, 114, 115
No. 5 flask design, 116
No. 6 defective casting report,
117
No. 7 forming working organ-
ization of foundrj^ 118
No. 8 computing weight from
pattern, 119
Facing molds,
how facings are applied, 18
mixing sea-coal facings, 19
sea-coal facings, 17
why molds are faced, 17
Fan blowers, 162, 163
Flask,
cheek, 21
cope, 21
drag, 21
floor flask, 23
pins for, 24
pressed steel flask, 24
slip jackets, 22, 23
snap, 21, 22
three part, 21
trunnions for, 24
two-part, 21
wooden flask dimensions, 25
INDEX
205
Fire brick, 157
Follow boards, 121, 122
making of, 122, 123
Foundry products and branches
of molding,
crane molding, 12
dry-sand molding, 11
floor molding, 11
iron molds, 11
green-sand molds, 11
loam molding, 12
skin-dried molds, 11
Gaggers,
making of, 40, 41
setting of, 41, 42
Gating molds,
bottom gating, 32, 33
common gates, 30
points to remember in, 29
pouring basins, 31, 32
skimming gates, 31
style of gates, 29
term gating, 29
Glossary of foundry terms, 199,
200, 201
Iron mixtures,
for light castings, 183
for medium sized castings, 184
for heavy castings, 184
Iron ores,
where found, 4
kinds of, 5
Ladles,
hand, 159, 160
linings for, 160, 161
Lining a cupola, 158
M
Manganese, 179
Master patterns, 120
Match plates, 123, 124
making of, 124, 125, 126
Metal patterns, 120, 121
Melting point of metals, 196
zone of cupola, 171
Mixing iron from analysis, 182,
183
from fracture, 182
Mixtures for core machines, 148
Molding and bottom boards, 25,
26
lumber required for, 26
Molding machines,
jarring, 130
roll-over, 130
stripping plate, 128, 129
squeezer, 127, 128
Molding sands,
care of, 15
coarse grained, 13
composition of, 13
fine grained, 14
nature of, 13
preparing of, 14
ramming of, 16
selecting of, 13
tempering of, 14
testing it, 15
where found, 13
Ladles,
bull, 159, 160
crane. 159. 160
N
Non-ferrous metal founding, 187
206
INDEX
Operating crucible furnace, 190,
191
Specific gravity of metals, 196
Silicon, 179
Stopping bars, 169
Sulphur, 180
Parting materials,
compounds, 19
lycopodium, 20
sands, 19
Pasting cores, 138, 139
Phosphorus, 180
Pig iron, 178
Pouring, 169
Questions for Part I, 51, 52
for Part II, 148, 149
for Part III, 195, 196
Tapping bars, 169
Tensile strength of metals,
Testing gray cast iron,
for flexure, 185
for hardness, 186
for shrinkage, 185
test bars, 184
testing machines, 184
Tongs, 190
Tools, 48, 49, 50, 51
Tuyeres for cupola, 155
Tuyere peep holes, 156
U
196
Record forms, 174 175, 176, 177
Remelting iron, 181
Upper tuyeres, 156
Venting molds, 16
Safety tuyeres, 156
Scrap iron, 180, 181
Shrinkage,
churning, 37, 38
feeding, 37, 38
of castings, 197
shrink holes, 34, 35
Slag holes, 156
W
Wedges, 46, 47
Weights, 27, 28
computations of, 28
of sand and gravel, 197
of metal per cu. in., 196
of metal per cu. ft., 196
DUE DATE
J UN l^ <
i^'Sv^
201-6503
Printed
in USA
TS230 Wendt, Robert Ernest
W4 Foundry work. New
1923 York, McGraw-Hill Book
Co., Inc., 1923.
12778
