Part 2

Tractors themselves come in many sizes and shapes. Some are built very high off the ground so they can pass over tall crops without hurting the plants. Some have four wheels that can be pushed close together for work in one field and pulled wide apart for work in another. Some have three wheels.

Mostly, farmers buy tractors the way people buy automobiles. They pick a model they happen to like and then argue that it’s the best in the world. Of course, a little light “cub” tractor is easier to handle than a big one, but it can’t do the hard work of a heavy model with huge rear wheels and tires. And here’s something about the tires--farmers often fill them with water instead of air to give them more weight when they grip the ground. In winter, these farmers must put antifreeze not only in the radiator but in the tires as well!

On enormous farms where very heavy work must be done, there are often crawler tractors to do it. Instead of tires they have caterpillar treads that give a better grip on the ground. Then they can pull a whole string of plows the way you see them in the picture, staggered out behind.

This kind of tractor was first named caterpillar by only one manufacturer. But people liked the idea, and they began to call all crawlers caterpillars.

A caterpillar is powerful enough to push a snow plow, too. Or it can bulldoze out a hole for a watering pond or a cellar for a new building.

BUILDING MACHINES

Charlie is the man who can tell you about driving a caterpillar tractor. He works in a city, helping to put up big buildings, and he knows how to use other construction machines, too. In fact, Charlie grew up with machines, for his father and his uncles and his grandfather were construction workers. It often happens that families pass along their knowledge of building from the older to the younger men, and they are very proud of their skills. Charlie uses the caterpillar tractor with a bulldozer blade to push heaps of earth and rock into a pile, ready for the shovel to load on a truck.

People often call the shovel a “steam shovel,” but that’s not its right name. You hardly ever see a real steam shovel any more. Years ago the big digging machines were driven by regular steam engines. Before they could start to work on a job, the men had to build a fire in the boiler and wait until they had enough steam pressure to make the shovel go. Of course, this wasted a lot of time. So, when very strong gasoline and Diesel engines came along, builders began using them for their shovels instead of steam engines.

Many shovels and other construction machines ride to work on long gooseneck trailers. They travel faster that way than they could on their own crawlers. And, in cities, the caterpillar treads might damage the pavement. To load and unload a shovel, the operator sets a short ramp of heavy planks against the trailer. Then the shovel creeps up and down on its own crawlers.

The kind of shovel that’s used on a job depends upon the work that must be done. If a basement has to be dug through hard rocky earth, Charlie may operate a crowd shovel, which crawls down into the hole. The shovel has a heavy dipper with teeth along the rim. When it digs, it crowds its teeth down into the ground. Charlie, sitting inside the cab, called the house, swings the dipper outward and up, then dumps the load into a truck.

Another shovel digs in the opposite way. It’s called a pull shovel. The teeth dig down and toward the driver. It can work from a bank and doesn’t have to go down inside the hole at all.

Sometimes Charlie uses a crane to get loose earth out of a hole. The crane has a long boom with wheels at the tip. Cables run over the wheels. Charlie fastens a kind of bucket called a clamshell to the cables. With its mouth open, the clamshell drops down over a heap of rocks and earth. Then Charlie starts machinery that pulls up on the cable. The jaws of the clamshell squeeze together and come up with a load of earth. Now Charlie swings the whole crane around till the clamshell is hanging above a truck. He pulls a cable that opens the bucket, and the earth and stone tumble out.

After the basement for a building has been dug, Charlie uses the crane for other jobs. Men hook the cables to heavy steel beams, and Charlie lifts them into position.

No matter what he is doing, he has a lot to watch out for. He must know which of four brake pedals to use at any moment and which of four hand levers to pull. One lever works the turntable which swings the whole house around. One moves the boom up and down. The other two control the cables.

At the same time, Charlie must watch what’s going on outside. A man stands on the job giving signals. Thumbs up mean “Take the boom up.” Thumbs down mean “Lower the boom.” When the signal man points up with his first finger, it means “Raise the cable.” If he wiggles the finger, it means “faster.” When Charlie is lifting a beam and has to hold it for a while in the air, he says he “takes a strain and dogs it off.” Dogging is his word for setting the brake on the cable.

Things are always likely to fall around a construction job, so the men who work on the ground have steel caps in their shoes to protect their toes. They wear steel helmets on their heads, too!

As the building goes up, Charlie’s crane lifts loads higher and higher. After a while he has to put a jib on the boom. This is an extension that makes it longer. When the building goes too high for his crane to reach, Charlie works another crane. It sits on top of the building’s framework and reaches down from there.

After Charlie lifts a big steel girder into position, other men bolt it in place then fasten it tight with rivets. A man called a heater gets the rivets red-hot in a fire. Using tongs, he tosses them one at a time to the catcher who reaches for them--not with a mitt but with a kind of cup. The catcher pokes a rivet in a hole, and two other men fasten it tight. One of them, the bucker, holds the rivet in position with a bar, and the rivet man pounds the other end flat with a rivet gun. (The gun works like a jack hammer, and it makes an awful racket.)

When you’re down in the street, it’s hard to realize that there may be a heavy wind blowing across the bare girders of a tall new building. High in the air, men have to keep their balance on narrow places and walk with sure feet. There are families who specialize in work far above the solid ground. Boys learn from their fathers how to walk safely without being afraid--although almost everyone is frightened at first. And, of course, everyone is careful. In New York a group of Mohawk Indians have worked on many high buildings where men like Charlie did the beginning work.

Once in a while Charlie helps to wreck an old building before putting up a new one. First, a crew of men go in and take away everything that can be used again or sold for junk. With specially made crowbars, they pry away floors and door frames. They take out furnaces and plumbing fixtures. Then Charlie gets to work with his crane. At the end of a cable he fastens a heavy steel ball, called a skull cracker. Then,

swinging the boom, he bashes the skull cracker into the wall of the old building. Over and over, the ball strikes the mortar and bricks. Cracks spread, and big chunks of the wall start tumbling to the ground. In a little while Charlie and his machine have made a heap of rubble out of a house that it took dozens of men to put up.

BUILDING A ROAD

Once Charlie worked on a road-building job. There he used a crane and a shovel and many other machines besides. This particular road had to cross a big swamp near the ocean. So the first problem was to fill up the swamp with something solid. In order to get enough earth and rock for the fill, men would have had to tear down a whole mountain. Instead they called in suction dredge machinery for the job. The huge pumps sucked sand from the bottom of the sea and poured it through pipes onto the swampy ground. When the water drained away, millions of tons of fine white sand were left.

Charlie helped level the sand off with a bulldozer. Then he moved on to a place where a hilly spot had to be leveled. There he drove a carrying scraper, a machine with a scoop between its front wheels and its rear wheels. The sharp scoop scraped up a load of earth, and Charlie drove off to dump it in a low spot. When he got there, a pusher blade at the back of the scoop pushed the earth out. Round and round he went, without having to stop for loading or unloading.

Other men used a different machine like the one in the picture. This earth mover carried more in one load than the motor scraper, and it was better for hauling earth longer distances. For very short hauls, Charlie drove a fast little tractor. At least it looked small compared to the giant machines. It pushed a scoop in front of it like a shovel, then lifted a load, turned swiftly and dumped the earth where it was needed a few yards away.

Charlie’s road was going to be a special highway for speedy traffic. In order to make it as safe as possible, the crossroads had to be lifted up over the new highway. Crews of men built these overpasses. First they used the huge earth-moving machines to make little hills on each side of the highway. Then they built bridges of concrete and steel between the hills.

At one place, there were two houses on the exact spot where the hill for an overpass had to be made. Instead of tearing the houses down, moving men just carried them away with the furniture still inside. First they raised the houses off the ground with jacks. Next a tractor backed a wide, low trailer up close to each house. Using special machinery and rollers, the men

eased the whole building onto the trailers. That same night, the houses were set down on new foundations, and the people went right on living in them.

At one place, a big ledge of rock was in the way of the new road. Men called powder monkeys blasted the ledge to smithereens with explosive. Then Charlie came in with his caterpillar tractor and a rock rake. Unlike a garden rake, which you pull, Charlie’s rock rake scratched up rocks and pushed them ahead of it. He shoved all the loose chunks of stone away, but several big ones were too far underground for the rake to pry them loose. So Charlie put a ripper on behind his tractor.

The ripper had strong prongs that could dig down deep and get a good hold on a boulder. The frame that held the prongs was hollow. For very heavy work, Charlie filled the hollow frame with sand to give it a lot of weight so the prongs wouldn’t slip. To pry out the very largest boulders, Charlie sometimes got another driver to hitch his caterpillar onto the ripper. Then the two tractors, chugging together, did the job.

After the bulldozers and scrapers and rakes had built a rough bed for the highway, Charlie helped to smooth it down and get it all ready for finishing. He used a long six-wheel motor grader for the job.

The motor grader had its Diesel engine in the rear, above the four wheels that did the pushing. The guiding wheels were way off at the front, and in between was the scraping blade, placed where Charlie could watch it.

Charlie could set the blade at almost any angle, just as a barber can tilt a long-bladed razor. And Charlie was proud of the way he had left the road almost as smooth as a barber leaves a man’s face.

Charlie could play tricks with the motor grader’s front wheels, too. Besides steering them in the ordinary way, he often made them lean over toward the right or the left. To look at them, you’d think they were broken, but they were only tilting to do a special job. They were actually in a tug-of-war with the blade and the earth it was pushing. The weight of the earth against the blade pulled the grader toward one side. But the leaning of the wheels pulled in the opposite direction. So the two pulls balanced each other. Charlie could guide the grader in a straight line without having a wrestling match with his steering wheel.

Charlie leaned his wheels when the grader went around a bend in the road, too. They helped the long machine to turn easily. If he had to back into a ditch,

he didn’t worry. The great wheels adjusted themselves to the sloping earth. All six wheels stayed on the ground, and the machine never got hung up the way a four-wheeled automobile would.

When the earth had been smoothed down, it was time to put the hard surface on. Trucks brought in crushed rock to make a solid bed. Concrete mixers covered the rock with concrete. And asphalt spreaders put a coat of asphalt on top.

Wherever the asphalt wasn’t spread evenly, men with rakes finished the job by hand. Then came the tandem roller to pack it down and make the surface smooth.

A Diesel engine moved the roller’s great weight quickly back and forth over the asphalt. In no time the road was as smooth as a table top. If the driver wanted to, he could turn his seat sideways. Then he could easily see whether he was guiding the roller straight forward and straight back.

Many people call road rollers “steam rollers.” That’s because the first ones really were driven by steam engines. Men have a lot less fuss and bother with a modern Diesel-engined tandem. There’s no need to start the fire or shovel coal to keep steam up. You can still see some steam rollers at work, though, because they are strong machines that last a long time. But when one wears out, it is replaced with a modern roller.

After the roller finished smoothing all the asphalt down, Charlie’s road was ready for traffic, but the job still wasn’t quite done. All along the highway the machines had left bare banks of earth. These had to be protected from the weather--just the way a house is protected with a coat of paint. The best coat for the earth is grass of one kind or another. So Charlie turned gardener. In some places he used the motor grader again to prepare the soil so that seed could be planted. With the blade of his grader hung away out at the side and pointed up in the air, he smoothed off the steep banks. Running along the edge of the road, he filled in the soft shoulders.

Then a seed-planter sowed the grass. And finally Charlie used the strangest machine of all. It chugged and puffed and spit out great mouthfuls of hay, which fell over the newly-planted grass! The hay protected the grass seed and kept it moist until its roots were growing strongly in the soil.

MORE ROAD WORK

The road was finished now, but some of the machines still had work ahead of them. In fact, road work is never ended.

All summer long, tractors pull mowing machines beside the highways, cutting the grass. Brush and small trees must be kept cleared away so that drivers can see ahead. In winter, the motor graders and the snow plows can keep the road clear. But in places where heavy snow piles up into drifts, caterpillar tractors often push special snow plows that eat through the drifts with powerful whirling blades. With one motion these plows dig out the snow and throw it off to one side of the road.

The caterpillar treads work better in snow than wheels with tires. So the “cats” are used all winter long in the Far North. There they even pull whole trailer trains on runners. The one in the picture is hauling Muskeg schooners, which are really trailer houses on sleds. Muskeg is an Indian word for swamp. The cats pull the schooners over frozen, snow-covered swamps.

You may wonder why anyone wants to use a trailer home in the roadless wastes of the Far North. The fact is that men work there the year round, prospecting for oil. When they think they have located oil there or anywhere else, well-drilling machinery goes to work.

DRILLING MACHINES

Everybody knows that oil wells and derricks go together. The tall derrick towers are needed to hoist drilling equipment in and out of the hole.

When men start to drill a well, they fasten a cutting tool, called a bit, to a piece of pipe which hangs upright in the derrick. Machinery turns the whole thing round and round, so that the bit grinds down into the earth. When one length of pipe, called a joint, has almost disappeared into the hole, men screw another joint onto the top of it. Now the engine turns the double-length pipe, and the bit digs down deeper.

Men, working on the floor and high up in the derrick, hoist more and more joints into position and screw them together as the bit goes on down. After a while, the bit gets dull. A new one must be put on. So, strong cables that run over wheels at the top of the derrick begin lifting the whole string of pipe out. Joint by joint, they unscrew the pipe and stack it out of the way. When the last joint comes up, men change the bit. Then back the pipe goes, joint after joint, into the hole.

Wells must often be drilled more than two miles deep before the bit breaks through into an underground reservoir of oil. That means that the string of drilling pipe must be two miles long. The machines that help to handle it are very strong, but on many rigs, men have to use their own muscles a great deal, too.

For deep drilling, the most modern rigs have a lot of fine new machinery. Automatic tongs take a tight grip on the drilling pipe when it is being unscrewed. Men used to work the tongs by hand. Mechanical hands

now keep the bottom joints from dropping back into the hole, and arms high up in the derrick do the job of stacking the pipe.

The skillful men who work with the pipes and the machinery call themselves roughnecks. The driller is the one who actually controls the drilling pipe. He never says he is digging a well. He says he is “making hole.”

Almost all deep wells are now drilled by the turning pipe and bit, which are called a rotary rig. But sometimes you can see an old-fashioned cable rig at work. It makes hole with a bit that pounds its way down into earth and rock. A cable raises the bit, and then lets it fall down with a bang that chips away a hole. On both kinds of rig, the hole is cleaned out with water. The water turns the rock dust into mud, which is then pumped out.

The cable rig idea is about two thousand years old! That long ago Chinese drillers made water wells, salt wells and even oil wells. The picture shows what one of these ancient rigs was like.

Look first of all at the long board attached to the rope that goes up over a roller and down into the well. Then look at the platform behind the board. Men jumped from this platform down onto the board. That jerked on the rope and pulled the drilling bit up in the well hole. When a man jumped off the board, the bit fell down and chipped away some rock. Round and round a whole crew of men raced, jumping onto the board and climbing back onto the platform as fast as they could. Still it took a long time to drill a well--sometimes as long as ten years.

Now look at the big wheel turned by a bull at the right. This wheel lifted the pipe made of hollow bamboo that you see at the left. The pipe was actually a bailer. Every once in a while the men poured water into the hole, let the bailer down and hauled up mud. Then the bit could go on drilling. Oil workers today still call the wheel which winds up cable “the bull wheel.”

PIPELINE MACHINES

When a well brings in oil, a new group of men and machines go to work. They lay a pipeline, through which the oil can be pumped to factories called refineries. Some pipelines are hundreds of miles long.

After surveyors have decided just where the line should go, bulldozers clear away brush, push over trees, heave big boulders to one side, making a wide pathway across country. In many places, the pathway is good enough for trucks to follow. They bring in lengths of pipe and lay them down end to end. Where the going is rough, a caterpillar tractor carries the pipe, one length at a time, hanging from a side-boom.

Now welding crews go to work fastening the ends of the pipe-lengths together. When they have finished, the “hot-dope gang” comes along. They are men who cover the pipe with a wrapping and then with a hot asphalt mixture to protect the metal.

Meantime, a wonderful machine called a trencher has been at work. This is a cat attached to a rig which

looks very much like an old-fashioned water wheel. Each bucket on the wheel has steel teeth. The cat turns the wheel and pulls it forward. The buckets scoop up earth, and spill it out onto a belt that dumps it in a heap at one side. The trencher plugs ahead, uphill and down, digging a ditch just the right width and depth.

Following behind the trencher, cats with booms hoist up the snaky pipeline and ease it over into the trench. Finally, bulldozers backfill the trench. That is, they cover the pipe with the dirt that the trencher left alongside. On one job, the men had to work at top speed in the desert and in rocky, mountainous country. They were all so glad they’d finally succeeded in getting the pipeline built that they put on a celebration. Whooping and hollering, they tossed their sweat-stained hats into the trench in front of the bulldozer as it backfilled the last few feet of earth.

Even after that there was one more tool that had work to do before oil could be pumped through their pipeline. It is a peculiar gadget that looks like a bunch of cowboy spurs hooked up with pieces of tin can and some old plates. The weird contraption is called the go-devil, and it has the job of traveling, perhaps hundreds of miles, inside the pipe, pushing out anything that could clog the line. Water pumped into the line behind the go-devil forces it through the pipe.

In one line, the go-devil brought out chunks of wood, pieces of rock--and several rabbits, skunks and rattlesnakes that had decided the pipe would make good headquarters! Now the powerful pumps could go to work shoving oil through the line.

MINING MACHINERY

Oil pumps today are much better and stronger than the first pumps ever built, but they are direct descendants of the ones that were invented for use in English coal mines long ago. In fact, those early pumps were the great-granddaddies of all modern machines.

Coal miners in England had dug so far beneath the surface of the earth that the shafts and tunnels were in danger of filling up with water. Neither manpower nor the power of horses hitched to pumps could do the tremendous job of keeping the mines dry. Something much stronger was needed. In order to find a new kind of power, inventors began experimenting with steam. The first workable steam engines were made to pump out coal mines more than two hundred years ago.

After a while steam engines began to pull trains over rails and drive ships through the water. They ran threshing machines on farms. Then inventors used their new knowledge about power to make other kinds of engines driven by gasoline or electricity or oil.

At last some of this new machinery began to work its way back into the mines. Power driven elevators carried the men up and down shafts to their work. But the miners still did all the coal digging and loading by hand.

Today many miners use power-driven drills for digging. Mechanical loaders pick up the loose coal and put it into small cars on the tracks in the tunnel. A little electric locomotive pulls the cars away to the elevator which hoists them up above ground.