HOW TO RUN A THRESHING MACHINE.
A threshing machine, though large, is a comparatively simple machine,
consisting of a cylinder with teeth working into other teeth which are
usually concaved (this primary part really separates the grain from
the husk), and rotary fan and sieves to separate grain from chaff, and
some sort of stacker to carry off the straw. The common stacker merely
carries off the straw by some endless arrangement of slats working in
a long box; while the so-called “wind stacker” is a pneumatic device
for blowing the straw through a large pipe. It has the advantage of
keeping the straw under more perfect control than the common stacker.
The separation of the grain from the straw is variously effected by
different manufacturers, there being three general types, called apron,
vibrating, and agitating.
The following list of parts packed inside the J. I. Case separator (of
the agitative type) when it is shipped will be useful for reference in
connection with any type of separator:
2 Hopper arms, Right and Left,
1 Hopper bottom,
1 Hopper rod with thumb nut,
2 Feed tables,
2 Feed table legs,
2 Band cutter stands and bolts,
1 Large crank shaft,
1 Grain auger with 1223 T. pulley and 1154 T., Box,
1 Tailings auger,
1 Elevator spout,
1 Elevator shake arm, complete,
1 Set fish-backs, for straw-rack,
1 Elevator pulley, 529 T.,
1 Beater pulley, 6-inch 1254 T., or 4-inch 1255 T.,
1 Elevator drive pulley 1673 T.,
1 Crank pulley to drive grain auger 1605 T.,
1 Cylinder pulley to drive crank 4-inch 973 T., or 6-inch 1085 T.,
1 Cylinder pulley to drive fan 1347 T., 1348 T., or 1633 T.,
1 Fan pulley, 1244 T., or 1231 T.,
1 Belt tightener, complete, with pulley,
1 Belt reel, 5016 T., or 1642 T., with crank and bolt,
4 Shoe sieves,
4 Shoe rods, with nuts and washers,
1 Conveyor extension,
1 Sheet iron tail board,
2 Tail board castings 1654 T., and 1655 T.
In addition to these are the parts of the stacker.
As each manufacturer furnishes all needed directions for putting the
parts together, we will suppose the separator is in working condition.
A new machine should be set up and run for a couple of hours before
attempting to thresh any grain. The oil boxes should be carefully
cleaned, and all dirt, cinders, and paint removed from the oil holes.
The grease cups on cylinder, beater and crank boxes should be screwed
down after being filled with hard oil, moderately thin oil being used
for other parts of the machine. Before putting on the belts, turn the
machine by hand a few times to see that no parts are loose. Look into
the machine on straw rack and conveyor.
First connect up belt with engine and run the cylinder only for a
time. Screw down the grease cup lugs when necessary, and see that no
boxes heat. Take off the tightener pulley, clean out oil chambers and
thoroughly oil the spindle. Then oil each separate bearing in turn,
seeing that oil hole is clean, and that pulley or journal works freely.
The successive belts may then be put on one at a time, until the
stacker belt is put on after its pulleys have been oiled. Especially
note which belts are to run crossed--usually the main belt and the
stacker belt. You can tell by noting which way the machinery must run
to keep the straw moving in the proper direction.
Oiling on the first run of a machine is especially important, as the
bearings are a trifle rough and more liable to heat than after machine
has been used for some time. It is well to oil a shaft while it runs,
since the motion helps the oil to work in over the whole surface.
The sieves, concaves, check board and blinds must be adjusted to the
kind of grain to be threshed. When they have been so adjusted the
machine is ready to thresh.
SETTING SEPARATOR.
It is important that the machine be kept perfectly steady, and that it
be level from side to side, though its being a little higher or lower
at one end or the other may not matter much. If the level sidewise is
not perfect the grain will have a tendency to work over to one side. A
spirit level should be used.
[Illustration: SECTIONAL VIEW OF THE AGITATOR SEPARATOR.]
One or more of the wheels should be set in holes, according to the
unevenness of the ground, and the rear wheels should be well blocked.
Get the holes ready, judging as well as possible what will give a true
level and a convenient position. Haul the machine into position and
see that it is all right before uncoupling the engine. If holes need
redigging to secure proper level, machine may be pulled out and backed
in again by the engine. When machine is high in front it can easily be
leveled when engine or team have been removed, by cramping the front
wheels and digging in front of one and behind the other, then pulling
the tongue around square.
Block the right hind wheel to prevent the belt drawing machine forward.
Always carry a suitable block to have one handy.
In starting out of holes or on soft ground, cramp the front axle
around, and it will require only half the power to start that would be
required by a straight pull.
In setting the machine, if the position can be chosen, choose one in
which the straw will move in the general direction of the wind, but a
little quartering, so that dust and smoke from engine will be carried
away from the men and the straw stack. In this position there is less
danger from fire when wood is used.
THE CYLINDER.
The cylinder is arranged with several rows of teeth working into
stationary teeth in what is called the concave. It is important that
all these teeth be kept tight, and that the cylinder should not work
from side to side. The teeth are liable to get loose in a new machine,
and should be tightened up frequently. A little brine on each nut will
cause it to rust slightly and help to hold it in place. If the cylinder
slips endwise even a sixteenth of an inch, the teeth will be so much
nearer the concaves on one side and so much farther away from them
on the other side. Where they are close, they will crack the grain;
where they are wide apart they will let the straw go through without
threshing or taking out the grain. So it is important that the cylinder
and its teeth run true and steady. If the teeth get bent in any way,
they must be straightened.
The speed of the cylinder is important, since its pulley gives motion
to the other parts of the machine, and this movement must be up to
a certain point to do the work well. A usual speed for the cylinder
pulley is 1,075 revolutions per minute, up to 1,150.
There is always an arrangement for adjusting the cylinder endwise, so
that teeth will come in the middle. This should be adjusted carefully
when necessary. The end play to avoid heating may be about 1-64 of an
inch. It may be remembered that the cylinder teeth carry the straw to
the concaves, and the concaves do the threshing.
THE CONCAVES.
The concaves are to be adjusted to suit the kind of grain threshed.
When desiring to adjust concaves, lift them up a few times and drop so
as to jar out dust. Wedging a block of wood between cylinder teeth and
concaves will in some types of separator serve to bring up concaves
when cylinder is slowly turned by hand.
There are from two to six rows of teeth in the concave, and usually the
number of rows is adjustable or variable. Two rows will thresh oats,
where six are required for flax and timothy. Four rows are commonly
used for wheat and barley. The arrangement of rows of teeth and blanks
is important. When four rows are used, one is commonly placed well
back, one front, blank in the middle. When straw is dry and brittle,
cylinder can be given “draw” by placing blank in front. Always use as
few teeth and leave them as low as possible to thresh clean, since with
more teeth than necessary set higher than required the straw will be
cut up and a great deal of chopped straw will get into the sieves, all
of which also requires additional power. Sometimes the teeth can be
taken out of one row, so that one, three, or five rows may be used. For
especially difficult grain like Turkey wheat, a concave with corrugated
teeth may be used, in sets of three rows each up to nine rows. The
corrugated teeth are used for alfalfa in localities where much is
raised.
THE BEATER AND CHECK BOARD.
After the cylinder has loosened the grain from the husk and straw, it
must still be separated. Some threshers have a grate under the cylinder
and behind it. In any case the beater causes the heavy grain to work
toward the bottom, and the check board keeps the grain from being
carried to rear on top of the straw, where it would not have a chance
to become separated. If the grain is very heavy or damp, there may be a
tendency for the straw to stick to the cylinder and be carried around
too far. In such a case the beater should be adjusted to give more
space, and the check board raised to allow the straw to pass to the
rear freely.
STRAW RACK.
The straw rack and conveyor carry the straw and grain to the rear with
a vibratory movement, causing the grain to be shaken out. To do good
work the straw rack must move with a sufficient number of vibrations
per minute, say 230. A speed indicator on the crank shaft will show the
number of vibrations best. Great care must be taken with this part of
the thresher, or a great deal of grain will be carried into the straw.
The less the straw is cut up, the better this portion of the machine
works; so the smallest practicable number of teeth in the concave
should be used.
The crank boxes and pitmans should be adjusted so that there is no
pounding. If the rear vibrating arms drop too low they get below
the dead center and are liable to break, at any rate causing severe
pounding and hard running. To prevent this, the crank boxes can be
moved forward by putting leather between them and the posts, or should
be otherwise adjusted. The trouble being due to the pitmans having worn
short, the pitmans may be lengthened in some way by putting pieces of
leather over the end or the like, or new pitmans may be introduced.
THE FAN.
The chief difficulty likely to arise with the fan is blowing over
grain. To prevent this blinds are usually arranged, which may be
adjusted while the machine is running so as to prevent the grain from
being blown over. At the same time it is important to clean the grain,
so the adjustment should not go to one extreme or the other.
In windy weather the blinds should be closed more on one side than on
the other. The speed of the fan must be adjusted to the requirements of
the locality.
As much blast should be used as the grain will stand, and heavy feeding
requires more wind than light feeding, since the chaff checks the blast
to a certain extent.
Care should be taken that the wind board over the grain auger does not
get bent, and it should be adjusted so that the strongest part of the
blast will come about the middle of the sieve.
SIEVES.
There is usually one conveyor sieve, which causes the grain to
move along, and shoe sieves, which are required to clean the grain
thoroughly. Different kinds of sieves are provided for different kinds
of grain, and the proper selection and adjustment of these sieves as to
mesh, etc., is of the utmost importance.
Much depends on the way the sieves are set, and on the rate at which
the thresher is fed, or the amount of work it is really doing. The best
guide is close observation and experience, both your own and that of
other threshermen.
CONVEYOR EXTENSION.
This carries the coarse chaff from the conveyor sieve to the stacker.
The conveyor sieve should be coarse enough to let all the good grain
through, as whatever is carried on to the extension must be returned
with the tailings to the cylinder. This means so much waste work. The
conveyor extension is removable, and should always be tight before
machine is started. See that it is.
When necessary, the grain may be run over a screen, which differs
from a sieve in that the mesh is small and intended to let dust and
small chaff through while the grain does not pass. The refuse from the
screen is dropped onto the ground. All screens have a tendency to
become clogged, and in this condition obstruct the grain and wind. It
is desirable not to use them except when necessary, and if used they
should be frequently cleaned.
TAILINGS ELEVATOR.
The tailings are carried back to the cylinder by an elevator usually
worked with a chain. This chain should be kept tight enough not to
unhook, yet not so tight as to bind.
To put the chain into the elevator, tie a weight on a rope and drop it
down the lower part of the elevator. The chain may be fastened to the
rope and a man at the top can then pull the chain up, while another
feeds it in at the bottom. When chain has been drawn up to the top,
the rope should be dropped down upper portion of elevator and used at
bottom to pull chain down after it has been adjusted over the sprocket.
Some one at the bottom should continue to feed the chain in as it is
pulled down, so that it will go into the elevator straight. When the
chain has been pulled through it may be hooked and adjusted to lower
sprocket, and tightened up by screws at top. Turn the chain around once
by hand to make sure there are no kinks in it.
The tailings should be small, containing no light chaff and little
full-size grain. They are a good indication of how the sieves are
working. If much good grain is coming through, see if it gets over the
conveyor sieve by way of the extension to the tailings auger, or over
the shoe sieve. If the sieves are not right, they may be adjusted in
various ways, according to the directions of the manufacturer.
Grain returned in the tailings is liable to get cracked in the
cylinder, and much chaff in the tailings chokes the cylinder. For every
reason, the tailings should be kept as low as possible.
SELF-FEEDER.
The self-feeder is arranged to cut the bands of the sheaves and feed
the grain to the cylinder automatically. It has a governor to prevent
crowding in too much grain, and usually a change of pulleys for slow
or fast feeding, as circumstances may require. In starting a new
governor the friction pulley and inside of the band should have paint
scraped off, and a little oil should be put on face of friction wheel.
The carrier should not start till the machine attains full threshing
motion, and to prevent this a few sheaves should be laid upon it. The
knife arms should be raised or lowered to adjust them to the size of
the sheaves and condition of the grain for cutting bands.
The cranks and carrier shaft boxes should be oiled regularly, but the
friction bands should not be oiled after it once becomes smooth.
THE WIND STACKER.
The wind stacker is arranged to swing by a hand-wheel or the like, and
also automatically.
Great care should be taken not to use the hand moving apparatus when
the stacker is set for automatic moving, as a break is liable to
follow. There is a clutch to stop the stacker, however. At times it
will be more convenient to leave off the belt that causes the automatic
movement.
By the use of various pulleys the speed of the stacker may be altered,
and it should be run no faster than is necessary to do the work
required, which will depend on the character of the straw. Any extra
speed used will add to the cost of running the engine and is a loss in
economy.
In moving machine with wind stacker in place, care should be taken to
see that it rests in its support before machine moves.
The canvas curtain under the decking, used to turn the straw into the
hopper, may need a piece of wood fastened to its lower edge to keep it
more stiff when stiff rye straw is passing. The bearings of the fan
and jack shafts should be kept well lubricated with hard oil, and the
bevel gears should be kept well greased with axle grease applied with a
stick. Other bearings and worm gear of automatic device should be oiled
with soft oil.
The attached stacker is simple in operation, and if it is desired not
to use the automatic swinging device but swing by hand, the automatic
gear may be thrown out. An independent stacker is managed in much the
same way.
ATTACHMENTS.
A weigher, bagger, and a high loader are usually used with a separator.
Their operation is simple, and depends upon the particular type or make.
BELTING.
The care of the belting is one of the most important things about
the management of a threshing machine, and success or failure will
depend largely on the condition in which the belts are kept. Of
course the hair side should be run next the band wheel. Once there
was disagreement among engineers on this point, but it has been
conclusively proven that belts wear longer this way and get better
friction, for the simple reason that the flesh side is more flexible
than the hair side, and when on the outside better accommodates itself
to the shape of the pulley. If the hair side is outermost, it will be
stretched more or less in going around the pulley and in time will
crack. Rubber belts must be run with the seam on the outside.
When leather belts become hard they should be softened with neatsfoot
oil. A flexible belt is said to transmit considerably more power than a
hard one.
Pulleys must be kept in line or the belt will slip off. When pulleys
are in line the belt has a tendency to work to the tightest point.
Hence pulleys are usually made larger in the middle, which is called
“crowning.”
Belts on a separator should be looked over every day, and when any
lacing is worn, it should be renewed at once. This will prevent breaks
during working, with loss of time. Some threshermen carry an extra set
of belts to be ready in case anything does break, and they assert that
they save money by so doing.
Lacing is not stronger in proportion as it is heavy. If it is heavy
and clumsy it gets strained in going round the pulley, and soon gives
out. The ideal way to lace a belt is to make it as nearly like the rest
of the belt as possible, so that it will go over the pulleys without a
jar. The ends of the belt should be cut off square with a try square,
and a small punch used for making holes. Holes should be equally
spaced, and outside ones not so near the edge as to tear out. The rule
is a hole to every inch of the belt, and in a leather belt they may
be as close as a quarter of an inch to the ends without tearing out.
Other things being equal, the nearer the ends the holes are the better,
as belt will then pass over pulley more easily. The chief danger of
tearing is between the holes.
A stacker web belt may be laced by turning the ends up and lacing them
together flat at right angles to rest of belt. Rubber or cotton belting
that does not run over idler or tightener pulleys so that both sides
must be smooth may be laced in this way. This lacing lasts two or three
times as long with such belts as any other, for the reason that the
string is not exposed to wear and there is no straining in passing
round pulleys.
The ordinary method of lacing a leather belt is to make the laces
straight on the pulley side, all running in the same direction as the
movement of the belt, and crossing them on the outside diagonally in
both directions. When belts run on pulleys on both sides, as they do on
the belt driving beater and crank, and also on wind stacker, a hinge
lacing may be made by crossing the lacing around the end of the belt to
the next adjacent hole opposite, the lacing showing the same on both
sides. This allows the belt to bend equally well either way.
The best way to fasten a lacing is to punch a hole where the next row
of lace holes would come when the belt is cut off, and after passing
the lace through this hole, bring the end around and force it through
again, cutting the end off short after it has passed through. This hole
must be small enough to hold the lace securely, and care should be
taken that it is in position to be used as a lace-hole the next time a
series of holes is required.
New belts stretch a good deal, and the ends of the lacing should not
be cut off short till the stretch is taken out of the belts.
Belting that has got wet will shrink and lacing must be let out before
belt is put on again. Tight belts have been known to break the end of a
shaft off, and always cause unnecessary friction.
Cotton or Gandy belting should not be punched for lacing, but holes
made with a pointed awl, since punching cuts some of the threads and
weakens belt.
HOW TO BECOME A GOOD FEEDER.
The art of becoming a good feeder will not be learned in a day. The
bundles should be tipped well up against the cylinder cap, and flat
bundles turned on edge, so that cylinder will take them from the top.
It is not hard to spread a bundle, and in fast threshing a bundle may
be fed on each side, each bundle being kept pretty well to its own
side, while the cylinder is kept full the entire width. A good feeder
will keep the straw carrier evenly covered with straw, and will watch
the stacker, tailings and grain elevator and know the moment anything
goes wrong.
WASTE.
No threshing machine will save every kernel of the grain, but the best
results can be attained only by care and judgment in operating.
It is easy to exaggerate the loss of grain, for if a very small stream
of grain is seen going into the straw it will seem enormous, though
it will not amount to a bushel a day. There are practically a million
kernels of wheat in a bushel, or 600 handfuls, and even if a handful
is wasted every minute, it would not be enough to counterbalance the
saving in finishing a job quickly.
Of course, waste must be watched, however, and checked if too great.
First determine whether the grain is carried over in the straw or the
waste is at the shoe sieve.
If the waste is in the conveyor sieve, catch a handful of the chaff,
and if grain is found, see whether the sieve is the proper mesh. Too
high a speed will cause the grain to be carried over. If too many
teeth are used in the concave, the conveyor sieve will be forced to
carry more chaff than it can handle. The blast may be too strong and
carry over grain, so adjust the blinds that the blast will be no
stronger than is necessary to clean the wheat well and keep sieves
free. If grain is still carried over, the conveyor sieve may be
adjusted for more open work, but care should be taken not to overwork
the shoe sieve. Be careful that the wind board is not bent so that some
grain will go into the fan and be thrown out of the machine altogether.
If the grain is not separated from the straw thoroughly, it may be due
to “slugging” the cylinder (result of poor feeding), causing a variable
motion. It may also be because speed of crank is not high enough.
Check board should be adjusted as low as possible to prevent grain
being carried on top of straw. See that cylinder and concave teeth
are properly adjusted so as not to cut up straw, while at the same
time threshing out all the grain. Sometimes heads not threshed out by
the cylinder will be threshed out by the fan of the wind stacker, and
the fault will be placed on the separating portions instead of on the
imperfect cylinder.
Grain passes through the cylinder at the rate of about a mile a minute.
The beater reduces this to 1,500 feet per minute. After passing the
check board the straw moves about 36 feet per minute. At these three
different speeds the straw passes the 17 feet length of the machine
in about 25 seconds. The problem is to stop the grain while the straw
is allowed to pass out. Evidently there must be a small percentage of
loss, and there is always a limit as to what it will pay to try to
save. Each man must judge for himself.
BALANCING A CYLINDER.
A cylinder should be so balanced that it will come to rest at any
point. In a rough way a cylinder may be balanced by placing the
journals on two carpenter’s squares laid on saw-horses. Gently roll the
cylinder back and forth and every time it stops, make a chalk mark on
the uppermost bar. If the same bar comes up three times in succession
it probably is light, and a wedge should be driven under center band at
chalk mark. Continue experimenting until cylinder will come to rest at
any point.
COVERING PULLEYS.
This is easily done, but care must be taken that the leathers are tight
or they will soon come off.
To cover a cylinder pulley, take off what remains of the old cover,
pull out the nails, and renew the wedges if necessary. Select a good
piece of leather a little wider than face of pulley and about four
inches longer than enough to go around. Soak it in water for about an
hour. Cut one end square and nail it to the wedges, using nails just
long enough to clinch. Put a clamp made of two pieces of wood and two
bolts on the leather, block the cylinder to keep it from turning, and
by means of two short levers pry over the clamp to stretch the leather.
Nail to the next wedges, move the clamp and nail to each in turn,
finally nailing to the first one again before cutting off. Trim the
edges even with the rim of the pulley.
The same method may be used with riveted covers.
CARE OF A SEPARATOR.
A good separator ought to last ten years, and many have been in use
twice that time. After the season is over the machine ought to be
thoroughly cleaned and stored in a dry place. Dirt on a machine holds
moisture and will ruin a separator during a winter if it is left on. It
also causes the wood to rot and sieves and iron work to rust.
Once in two years at least a separator ought to have a good coat of
first-class coach varnish. Before varnishing, clean off all grease and
oil with benzine and see that paint is bright.
At the beginning of the season give the machine a thorough overhauling,
putting new teeth in cylinder if any are imperfect, and new slats in
stacker web or straw rack if they are needed. Worn boxes should be
taken up or rebabbitted, and conveyor and shoe eccentrics replaced
if worn out. Tighten nuts, replace lost bolts, leaving the nut always
turned square with the piece it rests on. Every separator ought to be
covered with a canvas during the season. It will pay.
The right and left sides of a threshing machine are reckoned from the
position of the feeder as he stands facing the machine.
In case of fire, the quickest way is to let the engine pull the machine
out by the belt. Take blocks away from wheels, place a man at end of
tongue to steer, and back engine slowly. If necessary, men should help
the wheels to start out of holes or soft places.
Watch the forks of the pitchers to see that none are loose on the
handles, especially if a self-feeder is used. A pitchfork in a
separator is a bad thing.