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Charles Allen Bacon.

The Oliver plow book : a treatise on plows and plowing online

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way that there is under-drainage. Contrast this type of plowing with
that shown in the illustration below.



i




When plowing sandy loam the great object is to stir the ground for
aeration and leave it in such a manner that moisture will not unduly
escape, thus the crowning of the furrows, noticeable in the illustration
above, is entirely absent and the ground left as level as possible. These
two illustrations are good evidences of the fact that plowmakers are
striving to build bottoms that will do the soil the greatest possible good.



of landside surface to prevent the plow gouging into the
furrow wall and also to help keep the plow running level.
On breaking plows the shallow furrow requires an ex-



126



THE OLIVER PLOW BOOK




This method of laying the furrow when plowing sod insures the fewest
possible air spaces and vents for the continued growth of the inverted
grass blades.

ceptionally long and narrow landside to give the required
surface. On stubble and general purpose plows this
surface can be acquired by giving more height and not



PLOW BOTTOMS 127




One does not often see three different styles of plow bottoms on the
same plow. These bottoms are all cutting the same width and the same
depth but notice the difference in the delivery of the soil. The front plow
bottom is doing the quality of work this soil requires. The other two
are not the middle bottom doing better work than the rear one. The
front bottom is the same as that shown in illustration G; the second,
illustration F; the third, illustration K. Observe in the work f the
front bottom that the soil is completely turned over and well pulverized
and that the middle bottom turns the furrow over more completely than
the rear one.



so much length. In bottoms that are made for deep
plowing more attention is given to the height of the
landside than to the length because of the greater
amount of work being done by the mouldboard.

The amount of moisture in the ground, its looseness
and compactness, and amount of stubble, trash, roots
and sod are determining factors in the draft of plow
bottoms. Too much moisture in the ground adds draft
in the same manner as not enough moisture. Daily
changes in moisture cause great changes in draft.



128 THE OLIVER PLOW BOOK



Shallow plowing of sods puts more work on the share
and less on the mouldboard. Deep plowing of sod
lessens the work of the share and puts more work on the
mouldboard. The same is true of stubble.

The curvature of the upper part of the share, the
mouldboard, and the angle of the mouldboard to the
furrow slice have to do with the pulverizing qualities of
the bottom as well as the draft.

The increase in the speed of a plow in dry, hard
plowing aids materially in better pulverization, but
while it is doing better work it increases the power re-
quired. A plow bottom shaped to do the proper work
at a speed of two and one-half miles an hour will
throw the dirt from two to three times as far when
travelling at twice that rate of speed.



CHAPTER XIII



Plow Bottom Metals

THE farmer is often in doubt as to whether he should
use a chilled or steel plow. A knowledge of chilled
and steel metals as used in plows will enable a farmer
to determine for himself which type of plow he needs.

In steel plows of the best grade, the principal wearing
parts, the mouldboards and shares, are made from what
is known as soft center steel. This steel is composed of
three layers fused together. The two outside layers are
very high carbon to insure hardness. An extra hard
finish or temper is necessary to make the plow scour.
The center layer is of low carbon to impart toughness
to prevent the breaking of the brittle outside layers.

Steel plows thus made are successful for use in soils
for which they are adapted. The mouldboard of a steel
plow of the type described is only a quarter of an inch
thick and the grinding and polishing necessary to finish
the surface added to the natural wear, of course, wear
away much of this thickness so that sometimes the soft
center becomes exposed and the plow will no longer
scour. For this there is no remedy and a new part is
necessary.

While steel plows are, as a rule, lighter in weight than
the chilled, when it comes to the matter of draft the
chilled plow is by far the lightest in any or all soils for
which it is adapted. The draft of a plow is determined
not so much by the shape of its mouldboard and style of



130 THE OLIVER PLOW BOOK

share, as by the scouring qualities of the metal which
enter into its construction.

As a matter of fact, tests in draft of plows have been
made in the agricultural departments of universities.
These fsts have shown that chilled plows are lighter in
dn




fo process has yet been invented whereby steel can
tempered hard enough to prevent sand and stones
from deeply scratching the surface. Any farmer who has
land that is sandy in places knows, if he uses a steel
plow, that it refuses to scour after leaving the sandy
parts and enters the black or sticky land. This is
caused by the sand scratching the steel, leaving a feather
edge that ruins the dirt polish and makes an obstruction
to stop the shedding of the dirt.

Anyone who has never had this feature called to his
attention can observe the phenomenon by examining
his plow the next time he plows a piece of land in that
condition. This peculiarity of steel makes a steel plow
an exceedingly poor implement to use in any soil that
has sand, gravel or stones in it, because the plow wears
out too soon. It is like using a razor to sharpen lead
pencils too costly.

There is a type of land that steel plows turn to good
advantage and much better than chilled plows can, in
fact, where chilled plows will not work at all. Light
soils, loams free from sand, gravel, or stones, and black,
waxy dirt can be handled most successfully with the
steel plows, because they have in them the properties
necessary to make the dirt polish on the mouldboard
without scratching it. Wherever this condition prevails,
steel plows are the most successful, but when grit is
present the wear on the thin layer of hard steel on the



PLOW BOTTOM METALS



131




The toft of a steel share is perfectly smooth and has as uniform hard-
ness as it is possible to make.



Plow gunnels with and without
a piece of steel welded on the
bottom for reinforcing the point.
This metal is of the proper carbon
content to help keep the point from
wearing upward on the bottom.
It is illustrative of the efforts put
forth by plow makers to make steel
shares as durable as possible.
The projection on the edge of the
gunnel gives a wider welding
surface thereby making the share
stronger.




The bottom side of the share showing the position of the extra piece
of steel on the finished product. This gives strength and additional wear.



132 THE OLIVER PLOW BOOK

surface soon exposes the center which is so soft that it
will not scour in any soil.

Chilled plows are constructed by an entirely different
process. When the mouldboard is properly made it has
a flinty hardness that never has been duplicated in steel.
This hardness enables a chilled mouldboard to much
better withstand the scratching of sand, gravel, stones,
etc. As a matter of fact, there is no scratching that will
affect the scouring qualities of properly chilled metal.

As a result the more a chilled mouldboard is operated
in sandy soil the smoother it becomes, and the higher
polish it takes. Long experience has shown that used
plows have a better polish than can possibly be put on
in the factory. This peculiarity of chilled metal
makes chilled plows scour better in all kinds of sandy,
gravelly, stony, heavy clay soils, and the silt loams that
contain silica, potash, lime, iron and aluminum oxide.

The chill, as plowmakers call the term of hardening,
crystallizes the metal so that the grain is edgewise of the
mouldboard instead of lengthwise. This means that
the dirt in shedding passes over the ends of the crystals.

The ends of the metal crystals furnish the surface for
scouring. For this reason chilled mouldboards are very
hard to wear out. They often wear twenty years.
Instances are known where they have worn fifty years.
Chilled mouldboards have been used until the edge has
been worn to the thinness of a piece of paper and sharp
enough for a keen cut knife.

The thickness of a chilled mouldboard is about % to
}/2 of an inch. One-quarter of an inch of this entire
thickness is made of chilled metal, consequently, a
mouldboard will wear and scour until the entire thick-
ness of the chilled portion is worn away. When this is



PLOW BOTTOM METALS



133




The shin and point of this bottom show the effect of sand upon steel
bottoms. This sort of ground causes a steel bottom to wear out very
quickly-




metal. This sample of chilled metal showing the crystals
turned on edge explains why sand does not wear away chilled metal
as it does steel. The dirt, passing across the ends of the crystals, has a
tendency to polish chilled metal rather than to wear grooves in it.



134 THE OLIVER PLOW BOOK

compared with the thin layer of ^" of steel on the soft
center steel mouldboard, one can readily see that a
chilled mouldboard will outlast three steel. This fact
is what gave rise to the statement that one chilled plow
will outwear three steel in gritty conditions.

Properly chilled plows are not affected by rust. The
iron being needle crystal in form merely corrodes on the
end of the needle. The operator can scour a chilled
plow that has been exposed to the deteriorating weather
conditions for a long time in a few feet of travel with the
bottom in the ground. This feature of chilled plows is
in great contrast to steel plows which rust so easily that
the rust occasioned by a few days' exposure often makes
them hard to scour.

From the foregoing discussion on chilled and steel
plow bottoms, it is obvious that many farmers can use
both types of plows to good advantage, and where it is
possible to interchange the steel wearing parts with
chilled, the advantage is double because of the saving in
expense.

Oftentimes it is necessary to plow in the summertime
when the ground is hard and dry. The chilled share
being much more resistant to the hard earth will enable
a plowman to do better work by using chilled shares.
I

Experiments have been tried many times to determine
the amount of wear of chilled and steel shares. We
quote one experiment that was tried for this purpose and
the result. A two-bottom tractor plow was equipped
with a chilled and a steel share of the same size and type,
one bottom being equipped with a steel share and the
other with a chilled share. The ground in which the
experiment was tried was a sandy soil, very hard, with



PLOW BOTTOM METALS



133









This piece of chilled metal was buried eight years. The rusty surface
was scratched away with the back f a k n if e blade, revealing a perfectly
smooth and unfitted surface beneath.



The peculiarity
of the way each
metal wears is
plainly discerni-
'ble.



The points of
these shares are
illustrated on
page 136.



136



THE OLIVER PLOW BOOK





STEEL



NEW



USED

8
HOURS



some stones in it. The test was made the first of
September. The steel share was only used eight hours
and the chilled share fifty-one hours, thus showing that
the chilled share in this type of ground would outlast
six steel shares.



CHAPTER XIV



Scouring Troubles

ANY man who has ever operated a plow knows what
failure to scour means. A plow bottom must
scour if the best work is to be done.

The reason why plows fail to scour is very seldom
the same in any two fields, yet, underlying all these
causes are five fundamental facts. The first and most
common cause is the lack of an earth polish; the second,
improper plow adjustment; third, soil conditions; fourth,
soft spots or inequalities in the mouldboard; and fifth,
the shape of the bottom with relation to the soil texture.

The easiest way to overcome the lack of an earth polish
is to take the plow into hard ground and operate it until
this polish appears. A new plow coming from the fac-
tory is always covered with varnish or lacquer. This
should be removed before attempting to make the plow
scour. In removing the varnish it is better to use some
varnish remover preparation or strong lye solution.
Never use a sharp, steel instrument because it is very
apt to scratch the mouldboard. Whatever preparation
is used none of it should be left on the plow bottom any
longer than necessary to clean the bottom because a
solution that is strong enough to quickly remove the
lacquer will have a tendency to pit the surface if left
on for any length of time. The safest rule is not to
leave the bottom^from the start to the finish of the
cleaning.



138 THE OLIVER PLOW BOOK

When a plow mouldboard becomes pitted it must be
polished to the depth of pitting before it will scour.

If plows have this high earth polish and fail to scour
the trouble can nearly always be traced to soft spots in
the mouldboard, or to the soil itself. Assuming that the
mouldboard does not contain soft spots and the soil does
not contain enough silicon to scratch the mouldboard,
the trouble may be caused by the plow not running in a
true line of draft, or the soil is too loose for the proper
amount of pressure to cause the mouldboard to shed
properly, or it may be a combination of all these causes.

Side draft causes the mouldboard to work out of its
normal position, thus making unequal pressure of the
earth on the mouldboard.

The remedy for this trouble is to adjust the hitch so
that the plow bottom works in its normal manner.
Whenever a plow fails to scour it is always advisable
first to be sure that the plow is running correctly. If
this does not remedy the trouble lowering the plow an
inch or two will put more pressure against the mould-
board, thus forcing off the earth which may be clinging
to the bottom. It may be necessary to operate at this
extra depth long enough to put on a new polish. Often
times lowering the bottoms and travelling a distance of
fifteen to twenty feet will suffice.

Occasionally soils which scour readily have spots in
them that cause the plow to stick. These spots are
nearly always the result of a change in the soil texture.
That is, the spots where the plow sticks are caused by
the soil being looser. If the driver will watch these
places very carefully he can frequently cause the
plow to scour readily by increasing the speed when passing



SCOURING TROUBLES



139




A type of soil in which mouldboard plows were never known to scour.
Observe the soil sticking to the handle and the beam. . This soil is of that
type in which the soil particles have greater affinity for other substances.
Plow mouldboards covered with plaster of Paris and hog hides have been
known to turn this soil much more successfully than any metal.



Sectional view of ground plowed in the above manner. The ground
is merely pushed to one side and the top looks as though it might have
been broken up with any kind of an implement. These soils offer the
greatest opportunity for students who are interested in soil culture.



through, thus saving himself the necessity of cleaning
the bottom with a paddle.

If none of these remedies effect a cure look very care-
fully at the mouldboard, particularly at the places



140 THE OLIVER PLOW BOOK

where the earth sticks. If the surface of the mould-
board has a cloudy appearing spot and is darker than the
surrounding parts of the mouldboard, it shows that this
part of the mouldboard is softer than the rest. The
only remedy in a case of this kind is a new mouldboard.

If the surface has the appearance of being scratched
and the earth sticks there is no known remedy for this
trouble because a mouldboard plow has not yet been
made that will successfully scour in this type of soil.
The reason is that the soil is a mixture of very sharp
sand and silt. The silt, being of a plastic nature, fills
in the grooves made by the sand, thus destroying the
high polish of the mouldboard and making it absolutely
impossible for the plow to shed properly if the soil is
moist enough to make the silt plastic.




The scratched mouldboard cannot shed dirt properly whether it is of
the variety that sticks to the metal or not. The two illustrations on
page 141 show this bottom in sandy soil.

Another remedy that sometimes works to advantage
is the moving of the coulters to the landside of the
bottom. The object of this adjustment is to put an
additional weight of the furrow slice upon the shin of



SCOURING TROUBLES



141




This bottom was used in a sandy soil growing alfalfa. The purpose
was to find out whether a steel plow would shed this soil as successfully
as a chilled plow. The illustrations on pages 142 and 143 show the
chilled plow in the same field. The plow was drawn back in the
furrow and no effort made to clean the earth from the mouldboard.




This illustration shows the above plow in alfalfa sod. Observe that it
scours in one place and does not in another. This is characteristic of
the steel plow in gritty soils. It puddles the sandy soil which is bad for
aeration and helps to make it dry out quickly, paradoxical as it may



142



THE OLIVER PLOW BOOK



the plow, thus causing greater pressure. Sometimes
the coulters should be well forward, particularly when
the soil is loose, because the action of the coulter picks
up the fine, loose soil. The advanced position permits
the earth to drop on the furrow slice sufficiently in
advance of the plow bottom to prevent it from falling
on the shin.

Oftentimes turning the plow bottom on its wing will
start it to scour. This puts more pressure upon the
mouldboard and is a very good thing to do when the
trouble is caused by going from wet to dry soils or vice
versa.







The chilled bottom photographed after the experiment illustrated on
page 143. Observe there are no scratches on this mouldboard. The
dark points on the wing of the share and end of the mouldboard show the
high polish that the gritty soils put upon this bottom.



If it is noticeable, in all these different attempts to
make the plow scour, that the earth is being turned over
into clods and not pulverized properly, even though the
plow does scour for a few feet, the wrong bottom is
being used. The wise thing is to get in touch with some



SCOURING TROUBLES



143




The bottom palled back from the soil in the same manner as the steel
was. There is no earth sticking to the mouldboard nor is there any
indication of puddling of the soil.




Observe the plow is scouring all the time and that the soil has the ap-
pearance of being pulverized and well turned even though growth of
alfalfa was vigorous.



reputable plow manufacturer at once and have him
send an expert to look over the situation. All plow
bottoms are designed for the express purpose of invert-
ing the earth. It is not possible to design any one type



144 THE OLIVER PLOW BOOK

of mould that will turn all the different soils equally well.
The fact that clay soils hold together means that a plow
to successfully turn and pulverize them must not have
so bluff a mouldboard as is required for turning loose,
sandy soils. The tendency of clay particles for holding
together removes the necessity for as much bluff ness and
curvature in the mouldboard. As soils vary from one
extreme to the other, so must builders make plow bottoms
to meet these variations.

As a matter of fact, plow manufacturers have a large
variety of plow bottom combinations in order to prop-
erly plow soils of different textures.

It is a peculiar fact that in the waxy soils of Texas,
plow mouldboards have been made of steel, iron, glass,
brass, aluminum, plaster of Paris, and hog hides. The
peculiar part is that the plaster of Paris and hog hide
mouldboards worked more successfully in these soils
than any other type of mouldboard that has been
invented.

Whether the shape of a mouldboard has everything to
do with its scouring, assuming that it has the proper
degree of hardness, is a question open to debate. The
experiences gleaned from trying to develop a mould-
board that would work successfully in the waxy soils
of Texas developed so many sizes, styles and shapes of
plow bottoms that the plow bottom graveyard is full to
overflowing. These experiences must be regarded as
very strong evidence that something is required other
than the shape of the mouldboard and the material from
which it is made.






SCOURING TROUBLES



145




A never failing way to determine the soft spots in a mouldboard is to
take an old file and break it so that a sharp edge results. Run this
lightly over the mouldboard. The file will slide smoothly over the hard
parts. It will stick t the soft spots. Plow manufacturers are always
desirous of having their plows give satisfaction. After a little exper-
ience of this kind it will be easy to detect soft spots in mould boards from
their cloudy appearance. Soft spots never take the high polish that the
rest of the board does.



The reason given for the success of the plaster of Paris
board is that the plaster wears away with the earth.
This demonstrates that the adhesive force between the
earth and the plaster is greater than the cohesive force
of the plaster. It also demonstrates that the cohesive
force of the earth is greater than that of the plaster of
Paris.



146 THE OLIVER PLOW BOOK

The plaster wears away rapidly and the farmer is
obliged to recoat his mouldboard often sometimes
as often as every night. Considering that Texas
farmers have different sizes and shapes of plow bottoms,
it is plainly evident that the shape of the bottom does
not control its scouring qualities. The revolving disk
is the only type of steel plow at the present time that is
regarded as handling this soil successfully, but the disk
plow does not scour in these soils, showing that the ad-
hesive force of the steel disk and the earth is greater than
the cohesive force of the earth and also that the co-
hesive force between the two is greater than the adhesive
force of the earth particles.

If it is a question of constant pressure of the soil
against the mouldboard, it is necessary, then, in the design
of a mouldboard to shape it to interfere as little as
possible with the crumbling of sticky soils when turning
them over.

It is far from easy to design a plow bottom that will
always do these things satisfactorily. The Texas illus-
tration must be regarded as conclusive evidence that
the shape of the mouldboard is not the only factor to be
taken into consideration. The material from which the
mouldboard is made and the way it is made often have
more to do with the success of the bottom than its shape.
Very frequently a mouldboard that from all standpoints
of theory should do a better job than another type of
bottom does the poorer quality of work simply because
the mouldboard fails to scour.

Another side in scouring that is little known and has
received but spasmodic attention is the effect of heat
upon metal mouldboards.



SCOURING TROUBLES 147

One time a plow bottom designer was trying out a
bottom in sticky soil. The field was wet on one side
and dry on the other. The day was fearfully hot. In
the morning it was observed that the plow was scouring
successfully in the wettest and driest portions of the
field but where the two came together the plow refused
to scour on going into the wet portion and also refused
to scour on coming out. At noon the plow bottom was
cleaned and left standing where the sun had a good
opportunity to thoroughly heat it. The plow bottom
became very warm and the first two rounds in the after-
noon the plow scoured. After that the designer en-
countered the same trouble he had experienced in the
morning.

It is a matter of plow history that a Texas farmer
devised a pan arrangement back of the mouldboard,
well down towards the share, to hold burning corncobs.
The difficulty experienced in this device was the lack of
uniform heat on all parts of the plow bottom. Those
who witnessed the demonstration maintained that the
mouldboard scoured where the temperature was hot
enough, but failed to scour on other sections of the
bottom.

There may be more in this theory than some of us
think at the present time because it is a well known
physical fact that heat is the best agent for separating
molecules combined by adhesive force.

Oftentimes failure to scour cannot be attributed to


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Online LibraryCharles Allen BaconThe Oliver plow book : a treatise on plows and plowing → online text (page 7 of 10)