The history of the screw, and by inevitable implication, the screwdriver, is complicated. In One Good Turn: A Natural History of the Screwdriver and the Screw, Witold Rybczynski, professor of urbanism at the University of Pennsylvania, traces the metal fasteners to the 15th century, though it wasn’t until the early 18th century that the screw became common. Around then, gunsmiths developed purpose-built tournevis (French for “screwdriver”) for use in the intricate workings of early firearms. A century later, when screws could be mass-produced, factories cranked out accompanying screwdrivers.
According to the American Society of Mechanical Engineers, toolmaker Joseph Whitworth devised Britain’s first standardized screw in 1841. American engineer William Sellers did the same for his country in 1864. Standardized screw heads and screwdrivers emerged later. Early screws used either a slotted head or some sort of square or octagonal drive. As screw production increased, slotted drives became standard. But if you’ve ever cammed (slipped) a screw-head slot, you know why it’s not the only design. Enter Peter Lymburner Robertson. The official history from the Robertson Screw Company says that Robertson, a Canadian inventor and industrialist, cut himself when the blade slipped during a demonstration of a new spring-loaded screwdriver, forcing an epiphany that the world needed a new type of screw. Robertson designed a fastener that featured a square socket tapering towards a truncated pyramidal bottom, winning a Canadian patent for his work in 1907. It’s a brilliant design—Robertson screws won’t easily cam out, and the socket shape helps center the screwdriver, making one-handed operation easy.
The Robertson was perfect for the burgeoning auto industry. Ford began using it to assemble Model Ts at its Windsor, Ontario, plant, where the screw’s time-saving qualities reduced costs by a significant $2.60 per car. But unless you’re Canadian, there’s a good chance you’ve never heard of Robertson screws. That’s because Henry Ford wanted to use Robertsons in all of his plants, and he wanted more control over how they were made. Robertson, by most accounts a stubborn man, wouldn’t agree. No deal was struck, and the Canadian lost an important part of his business. Meanwhile, other engineers worked on their own types of screw heads.
According to Rybczynski, the one that stuck came from inventor John P. Thompson and businessman Henry F. Phillips. A Phillips screw offers many of the benefits of a Robertson and can be driven by a traditional slotted screwdriver in a pinch. Phillips licensed his design to the giant American Screw Company, which got General Motors to use the screw in the 1936 Cadillac. Within the decade, almost all automakers were using Phillips screws.
A Phillips is, arguably, not a better screw than a Robertson. Consumer Reports once wrote that “compared with slotted and Phillips-head screwdrivers, the Robertson worked faster, with less cam-out.” However, cam-out was good for automakers increasingly relying on automation, as it meant screws wouldn’t be overtightened. Today the Phillips is the standard, except in Canada, where the Robertson remains popular, and in Japan, which has its own cruciform screw, the Japanese Industrial Standard.
Next time you strip out a Phillips, shake your fist at Henry Ford.
Original article by Engine Builder > Some of the most stressed out parts of a high-dollar performance engine are the relatively inexpensive nuts and bolts that hold it all together. If you’re building a performance engine – whether it’s for the street or the racetrack – using stock fasteners in the most critical areas could be asking for trouble. That tricked-out stroker crank and rods and flowed set of heads may be in jeopardy if you bolt it all together using stock or otherwise inferior fasteners.
No matter what the application, there is not one fastener that is right for every job.
Different materials and designs have different advantages in different applications, and selecting the right fastener for the job may be difficult at best when choosing from such a wide array of materials. Variables such as strength, temperature, movement, vibration and fatigue all come into play when deciding on the right bolt or stud. The following article details some of the basic definitions and facts about fasteners that’ll show you why not all fasteners are the same.
Tensile strength is the most common mechanical property that is referred to when talking about fastener strength. It is the maximum tension-applied load the fastener can support before it fractures.
Fatigue in a fastener can cause sudden, unexpected failures. A fatigued fastener can fail even when loads are below the strength of the material due to operating under constant cyclic loads. Fatigue strength is often defined as the maximum stress a fastener can withstand for a specified number of repeated cycles before it fails.
Some of the most important fasteners in the engine such as cylinder head bolts, connecting rod bolts and main bearing and cap bolts are subject to fatigue forces. It is important to use fasteners with high fatigue strength, as well as the tensile strength, to hold the joint together under high-pressure forces in these applications.
Torsion strength is typically the amount of torque or friction a fastener can safely handle before it breaks. One thing to remember is that when torque is applied to a fastener, most of the input is spent in overcoming friction. Roughly 85-95 percent of the energy you have spent tightening the fastener is lost, leaving only about 5-15 percent in actual clampload. Because of this, any slight variation in friction can lead to significant changes in resulting preload conditions.
These variables include surface roughness, surface finish, lube, load-range, dimensions, temperature and torque sequence. This is why it’s so important to achieve consistent friction conditions and to use the methods that allow the most consistent torquing. So the preload target will depend on the lube you use (most use a Moly lube or 30 weight oil) and the tightening sequence.
Each material has a certain amount of elastic range, meaning the fastener can be stretched to a certain point but when the load is released it can return to the original shape. But if the load applied exceeds the elastic range and therefore causes the fastener to go past the yield point, it then reaches what is called the plastic range of the fastener. The fastener material is no longer able to return to original size.
The proof load is an applied tensile load that can be applied before permanent deformation. It represents the useable range of a fastener before it goes into its “plastic range” where it cannot return to its original size and shape. At this point of yield, permanent elongation of the fastener sets in. If you continued to load the fastener, it will reach its ultimate tensile strength in which “necking” or elongation occurs until it is stretched to the point of breakage.
Shear strength is the maximum load a fastener can take before it fails when it is applied at a right angle to its axis. A load occurring in one transverse plane is called single shear, while a load that is applied in two planes, where a fastener may be sliced in three pieces, is called double shear.
Racing applications require high quality, precision tolerance fasteners to achieve the clampload and fatigue strength that is needed in a harsh environment where there are extreme forces placed against them. Materials used to make fasteners vary with the application and load carrying needs.
The most common high-grade material is medium carbon alloy steel that is used in making SAE J429 Grade 8 bolts. These bolts are often used by OEMs in high stress applications and in some racing applications and are rated at 150,000 psi tensile and 130,000 psi yield with a proof load of 120,000 psi.
“One of the issues with Grade 8 bolts is that there are some areas where you really don’t want to use them,” says Doc Hammett, Totally Stainless. “If there’s a cycling load on them you could start to get into trouble. A classic example was on the old belt drives where street rodders were using Grade 8 for accessories and they were breaking bolts all of a sudden. Many were left scratching their heads until someone figured out the bolts were fatigued. The higher the carbon steel the more they are prone to fatigue. Fastener manufacturers add other alloys to carbon steels and change the properties to suit their specific needs. This is one of the most interesting things about steel: you can add a little bit of something and make the properties change drastically.”
Hammett says one of the biggest things that Totally Stainless has done recently is to introduce large high-strength stainless bolts. Stainless steel by definition is anything with at least 12 percent chromium in it. “There are over 1,000 different alloys of stainless,” says Hammett. “What people generally think of is 300 series stainless is generally a low strength material and is not heat treatable. The most common 300 series is an 18-8. It’s 18 percent chrome and 8 percent nickel. The tensile strength for 1/2? and larger 18-8 stainless bolts is no more than 80,000 psi and the yield strength is only 45,000 psi. We use 17-4 PH for our high-strength bolts, this material is heat treatable and has a tensile strength of 200,000 psi and a yield strength of 175,000. We electro polish them, which makes them more corrosion resistant.”
Don Trapp of A1 Technologies says his company starts out with the basic alloy 4340 or 8740 that is 190-ksi minimum. From that point it goes up to 280 ksi. “The 4340 or 8740 is already far above an OEM fastener in strength and quality. We use a lot of H11, which is a toolsteel for Top Fuel, Funny Car and some in Top Alcohol and Injected Nitro classes use it also. This is a 240 ksi minimum graded material.”
Trapp says almost every team in the top classes of drag racing uses this bolt material, because these cars are some of the most extreme applications. “As far as boost for superchargers and horsepower, to clamp a head and main studs down on a Top Fuel engine is a pretty extreme proposition. We also use this material quite a bit in Sport Compact classes because they use extreme boost levels in many cases. There are many teams running 60 lbs. of boost on top of high compression, so the cylinder pressures are what you would call extreme.”
The next step up from 4340 or 8740 steel is 1722 (AMS 6304). Manufacturer ARP calls it ARP 2000 and it’s all the same material, a 220 ksi material. The next step would be H11, which ARP calls L19. It too is the same material and also comes from Carpenter. Those are getting up to 240-250 ksi. You can go higher than that but it becomes brittle, according to Trapp.
The next step up include two materials: Custom Made 625 and Aerospace Material Specification (AMS) 5844. Trapp says A1 Technologies gets both materials from Carpenter as well. “The AMS 5844 has a trademark name MP35M, which means it’s multiphase,” says Trapp. MP35N is an age hardenable Nickel-Cobalt base alloy that has a unique combination of properties – ultra high strength, toughness, ductility and outstanding corrosion resistance. MP35N resists corrosion in hydrogen sulphide, salt water and other chloride solutions. ARP calls this material ARP 3.5.
Both of those materials are considered a super alloy and are a very high nickel base. The last two are stainless steels because there’s so much nickel in them. One is mostly nickel and the multiphase is Nickel-Cobalt. Right now the multiphase is about the strongest fastener material out there. But the material alone is $75 a pound before anyone begins making the fastener.
There is definitely a relationship between torque and preload, but there is some confusion as to the difference. With connecting rods it is not too difficult to use the stretch method and to measure the preload by measuring stretch. But in head bolts it is much more difficult to measure and you’re basically reliant on the torque wrench to stretch the bolt. A torque wrench needs to be recalibrated often and you need very clean threads that have been burnished in so there is very little friction. The preload is the force on the bolt that clamps the joint together. Torque, however, is just the mechanism used to get the desired preload.
There’s a huge difference in torque depending on what type of lube you use, whether it’s engine oil or extreme pressure lube (EPL), which is used quite a bit in NASCAR for instance. Trapp says A1 Technologies doesn’t recommend any particular type of lube. “We normally recommend that the higher the torque is the more efficient lube you use. It’s better for the fastener and the torsional stress. Friction can take up to 80 percent of the torque to overcome so the more you can reduce friction, the less torsional force you put on the fastener and the more effectively you’ll stretch the stud, which is really the goal.”
Generally, when you torque the stud you put a certain amount of stretch on it. The smallest diameter of the stud is where the stretch is going to occur. So if the threads are your smallest diameter, that’s where it will stretch. If you make the body smaller (undercut), then you begin to make the stretch in the body of the fastener be it a stud or a bolt, as opposed to making it occur in the threads. That’s why in a rod bolt, you rarely see one that doesn’t have an undercut. Head studs, depending on the application, you may have an undercut or you may have an in-between or full-body stud.
An in-between doesn’t elongate much while achieving its clampload as opposed to a full undercut stud that will actually elongate a little further. One stud may stretch .005? to achieve 20,000 lbs. of clampload. The other one may stretch .0075? to get the same amount of clampload.
You can reuse any bolt as long as you don’t get into the yield of the bolt and stay within 80 percent of its yield strength. You can still yield even a very strong fastener so it’s a one time only use fastener. It depends on what you want to design and what torque you utilize.
“There’s a whole world of fasteners out there that engine builders need and that industrial suppliers just don’t have. That’s why we are in business,” says Totally Stainless’ Doc Hammett. Keep this in mind next time you are looking for fasteners for your performance build.
Like the screw, the bolt occupies an integral position in both industrial and everyday life. In fact, bolts and screws are used more than any other type of mechanical fastener, and they can be found in nearly every simple or complex machine. Although there is no absolute distinction, the difference between screws and bolts can be broadly defined as one of thread size and tapering. Bolts are generally larger and do not have tapered ends. In standard usage, a fastener that is torqued with a nut is usually considered a bolt.
Without bolts, we would not be able to hold together the frames of cars or the arms and backs of chairs. A device as common as a pair of scissors or as sophisticated as a particle accelerator would be rendered inoperable. The self-evident utility of the modern bolt makes it all the more interesting to discover how this object came to be so crucial to our way of life. In the United States alone, the bolt has undergone several distinct stages of development.
The Origins of Bolt Production
Bolt usage can be traced back to ancient irrigation systems and construction projects, but metal bolts and screws did not become the standard until the early modern era. The first machines used to produce metal bolts resembled cutting lathes and were invented in France in the mid-sixteenth century. However, it wasn’t until the nineteenth century and the beginning of mass production that bolts became the norm in industrial manufacturing.
In the United States, the first systematic bolt manufacturing operation was founded by Micah Rugg in 1818. Rugg was a Connecticut blacksmith who developed a process of cutting and heating square iron bars into bolt-sized pieces. These workpieces were then smoothed along an anvil, and a die-cutting press was used to shape the bolt’s head and threads. Using machine tooling processes, such as drop hammering and die trimming, proved to be both time- and cost-efficient. By 1840, Rugg had sold several thousand bolts and expanded his operation to produce nearly 500 bolts a day.
Following the success of Rugg’s pioneering bolt production methods, other manufacturers began developing new technologies and techniques to capitalize on the burgeoning fastener market. William Clark, another manufacturer from Connecticut, is credited with designing the first bolts and dies made from round, rather than square, iron in the 1860s. Clark also streamlined the bolt head formation process by using die compression to create both the head and the angled neck in the same operation. His pinched and concave neck bolts proved highly cost-efficient and reduced the risk of splitting wood when driving the bolts into a workpiece.
Some of the other new bolt configurations that emerged over the next thirty-year period included:
Star Bolt: This was a pinched neck bolt similar to Clark’s first design that eventually fell under his patent.
Bastard Neck Bolt: The bastard neck configuration had a thin bolt head and a short rectangular shank.
Fin-Head Bolt: This bolt was designed with narrow lugs underneath the head that helped keep it steady while a nut was being tightened or removed.
By 1905, there were over five hundred factories in the United States specializing in bolt and nut production. Part of the skyrocketing demand for bolts in the later half of the nineteenth century was driven by the spreading utility of new bolt designs.
Current Production Methods
The twentieth century saw the development of our present-day bolt manufacturing methods, particularly through the advances and armaments engendered by the two world wars. Although these techniques greatly expanded previous production capabilities, they were similar in principle to the original processes established in the 1800s. For example, the cold-forging technique used today hearkens back to the cold-forged fin-head bolts first developed in 1890.
The majority of current bolt manufacturing methods employ cold-forged heading to shape a steel workpiece. A gripping die holds the metal stock in place while a concave compression punch forms the bolt’s angled round head. The bolt’s shaft is then deformed through the thread rolling process, which uses cutting dies to shape threads into the metal shaft. The bolt is then usually coated with anti-corrosive substances to strengthen its durability. Hot or cold blackening and galvanization may be used to chemically bond a sealant, such as oil, onto the bolt in order to extend its working life. While these methods are more cost-efficient, boast higher production rates, and create less waste than the older methods of the nineteenth century, the modern-day bolt still owes its design and central attributes to the pioneering efforts of early manufacturers.
It’s always a surprise when you learn something new or interesting about a subject you thought you knew everything about. Well fasteners are pretty cut and dry, right? Read on for a few facts about fasteners that may amaze you!
Fastener Fact 1
If you’ve ever designed a part with a tapped hole, you may have wondered, “How many threads do I need to make a strong connection?” The answer is that it varies, but six at most. Because bolts stretch slightly when load is applied, the loading on each thread is different. When you apply a tensile load on a threaded fastener, the first thread at the point of connection sees the highest percentage of the load. The load on each thread decreases from there, as seen in the table below. Additional threads beyond the sixth will not further distribute the load and will not make the connection any stronger.
Fastener Fact 2
There is a common misconception that black-oxide alloy steel socket head cap screws (SHCS) are ‘grade 8’. This is believed because grade 8 fasteners are so widely available that the label has become associated with all high-strength fasteners. Technically speaking, to be considered ‘grade 8’, a fastener has to meet industry standards for various characteristics. Three of the most important physical properties of SHCS are inconsistent with the ‘grade 8’ classification: tensile strength, hardness, and markings on the bolt head. SHCS are actually stronger than ‘grade 8’, and have more in common with grade 9 fasteners.
Fastener Fact 3
When a bolted connection will be subjected to a fatigue loading, you want to tighten the bolt up to its yielding point for maximum strength. A bolt will experience zero change in load if the applied tensile force is less than the compressive force of the connection. So, a tightly fastened connection is better suited to withstand fatigue loading than a loose connection because the bolt itself will not sense the fatigue load, only the constant force applied due to the clamping of the joint. To ensure that the connection is properly fastened, you can look up the recommended torque for a given fastener type in a table like the one found here. If the applied torque is critical for your application, make sure that you apply the recommended torque to the head of the bolt, rather than the nut. Torquing the nut can result in different nut factors and change the torque required to achieve proper pre-load.
Fastener Fact 4
Have you ever seen a fastener labeled with a 2A or 3B rating and wondered what that meant? That number-letter combo is used to indicate the thread class of the fastener. Thread classes include 1, 2, 3 (loose to tight), A (external), and B (internal). These ratings are clearance fits which indicates that they assemble without interference. Classes 1A and 1B are rarely used, but are a good choice when quick assembly and disassembly are a priority. Classes 2A and 2B are the most common thread classes because they offer a good balance between price and quality. 3A and 3B are best used in applications requiring close tolerances and a strong connection. Socket cap and socket set screws are usually class 3A.
Fastener Fact 5
All fasteners are available with either coarse or fine threads, and each option has its own distinct advantages. Finely threaded bolts have larger stress areas than coarse bolts of the same diameter, so if you are limited on the bolt size due to dimensional constraints, choose a fine thread for greater strength. Fine threads are also a better choice when threading a thin walled member. When you don’t have much depth to work with, you want to utilize their greater number of threads per inch. Fine threads also permit greater adjustment accuracy by requiring more rotations to move linearly.
On the other hand, coarsely threaded bolts are less likely to be cross threaded during assembly. They also allow for quicker assembly and disassembly, so choose these when you will be reassembling a part often. If the threads will be exposed to harsh conditions or chemicals, a coarsely threaded fastener should be considered for its thicker plating or coating.
Fastener Fact 6
When designing a clearance hole for a bolt, it helps to refer to a chart to pick the correct hole size. A useful reference can be found here. Similarly, when pre-drilling a hole that is to be tapped, it helps to have a chart to refer to the appropriate size pilot hole. Such a chart can be found here.
You need to get 500 tons of supplies from Fairbanks, Alaska to the Arctic Ocean—a journey of about 400 miles through pure wilderness. There are no roads, very few airstrips, and endless ice. You’re going to have to withstand minus 68 degree temperatures. Also, nuclear armageddon is on the menu if you’re not quick about it.
You, my friend, need a LeTourneau land train.
The DEW Line
By 1954, with the Cold War well underway, the U.S. government realized the quickest way to get a nuclear bomber from Russia to America was to go right over the Arctic Circle. If we wanted any chance of preventing a nuclear apocalypse, we needed to know if Soviet bombers were crossing the North Pole as soon as possible. The Army planned to build 63 manned radar stations in the high Arctic around the 69th parallel (200 miles north of the Arctic circle) as a result. And to transport all the necessary material that far north, it would have to get creative.
Working together, Canadian and American governments determined they would need about 500 tons of materials to construct all of these outposts. With no suitable runways or ports and heavy lift helicopters still in their infancy, it would all have to be hauled in over land. The task of figuring out how exactly to get that done fell to the same company that had been chosen to build the stations themselves—The Western Electric Company, a subsidiary of AT&T.
Solving unsolvable logistics issues wasn’t exactly its forte. But with the help of TRADCOM (U.S. Army Transportation Research and Development Command), it found the one company—more accurately, the one man—that might be able to help.
That’s R. G. LeTourneau To You
Born in 1888, Robert Gilmore LeTourneau was an inventor of heavy machinery. In WWII, 70 percent of the Allies’ earthmoving equipment was created by LeTourneau Technologies, Inc. Having very little formal education, LeTourneau began his working career as an ironmonger. By the time he died in 1969 he was tremendously wealthy and personally held nearly 300 patents. He is buried on the campus of the University he founded in his name, where his gravestone reads “MOVER OF MEN AND MOUNTAINS.” Just a little character development for you.
LeTourneau had spent the early 1950s perfecting a sort of diesel-electric drivetrain for multi-wheeled heavy-machinery. The system—somewhat similar in concept to the sort used on many locomotives—used a combustion engine to spin an electric generator. This generator would send its power to hub motors mounted to each wheel of the vehicle, allowing for multi-wheel-drive without differentials, driveshafts, or the drivetrain losses associated with them.
This powertrain setup will sound familiar to anyone who read our story on the doomed Antarctic Snow Cruiser earlier this month. But LeTourneau’s design was clearly a generation ahead of Thomas Poulter’s hub motors, which weren’t geared properly to handle anything beyond a gentle incline.
The VC-12 Tournatrain
LeTourneau originally applied this technology to scrapers and graders, but realizing the scalability of such a system, he soon moved beyond just earthmoving. In 1953, he dreamed up the first trackless land train to assist logging operations, the VC-12—a four-wheeled control cab with a 500-horsepower Cummins diesel connected to a generator, pulling three cargo trailers on giant, rugged tires, all of which were powered by hub motors to make it a true 16-wheel-drive vehicle. It was brutally ugly, but critically, it worked.
Developed to haul lumber out of forests over rough terrain, the VC-12 had a hauling capacity of 140 tons. A second version saw LeTourneau add three more cargo trailers and another control cab out back with a second Cummins diesel, much like a real train would be set up with multiple locomotives. TRADCOM caught wind of the project and asked for a demonstration.
TRADCOM came away impressed. This would be the vehicle to help engineers build up the DEW Line, or at least a version of it. The government decided to pay for the construction of a prototype control cabin built by LeTourneau and designed specifically for Arctic conditions. The result? The TC-264 Sno-Buggy—and, incidentally, monster trucks.
Entering the Arctic With a Giant Machine
The Sno-Buggy had a single, 28-liter Allison V-1710 V12, the same engine used in many American fighter aircraft during WWII including Lockheed’s P-38 Lightning. In this application, it ran on butane and powered a generator, which in turn sent the juice to four hub motors, each spinning two massive 10-foot-diameter wheels. There was no suspension system; any cushioning was provided by the low-pressure tires instead.
Speaking of those huge wheels, four of them eventually made their way to the iconic Bigfoot monster truck (Bigfoot IV and V, to be exact) in the 1980s after owner Bob Chandler bought them from a Seattle-area junkyard for $1,000.
The Sno-buggy had an exceptionally large contact area on the ground, which allowed it to spread its weight over the soft snow and ice. As a result it excelled when tested in Greenland in 1954, and both the U.S. Army and Alaska Freightlines (the Seattle-based company Western Electric contracted to transport their freight north) were impressed enough to order a pair of overland trains. Alaska Freightlines’ rig was the first to be completed, dubbed the VC-22 Sno-Freighter.
Two Trains to Send North
The VC-22 was quickly assembled in a little more than a month. This is impressive considering it was one of the longest (if not the longest) off-road vehicle ever built at the time, with its six cars (including the locomotive) measuring a total of 274 feet. Each car had four driven wheels, resulting in 24-wheel-drive courtesy of two 400 horsepower Cummins diesel engines and the now-familiar hub motor setup. It had a payload capacity of 150 tons.
Thanks to its 7.3-foot-tall wheels and tires, it could traverse nearly any terrain. It had a very successful first season hauling freight to the DEW Line, but a year later it jackknifed and a fire started in the engine room that rendered it inoperable. Soon after, Alaska Freightlines’ contract with Western Electric ended and the VC-22 was hauled out of Canada and left on the side of a highway in central Alaska, where it remains to this day.
Seriously, it’s visible in both Google Maps satellite images and the Street View perspective from Steese Highway outside Fox, Alaska. See for yourself.
Sometime after the VC-22 was completed, the Army’s more complex machine was also finished. Donning the same 10-foot wheels as the Sno-Buggy that impressed officials, the so-called LCC-1 had four cars including an articulating locomotive at the front. Its 600-hp diesel engine sent power to all sixteen wheels, and it was capable of hauling 45 tons.
This machine led a much longer and more successful life than the VC-22. Dispatched to Greenland, it hauled cargo all over the region from 1956-1962. But it too was eventually abandoned in an Alaska salvage yard before being rescued and put on display at the Yukon Transportation Museum in Whitehorse, Canada, where it’s also visible from space on Google Maps.
It might not sound like it, but the Army was very impressed with the LCC-1’s capabilities. So in 1958, officials commissioned the construction of its successor, the longest off-road vehicle ever and LeTourneau’s final triumph: the TC-497 Overland Train Mark II.
LeTourneau’s Gas Turbine Land Train
The TC-497 is a truly remarkable feat of engineering. Capable of hauling 150 tons at 20 mph for nearly 400 miles (this range could be extended by carrying extra fuel cars), it was powered by four 1,170-hp gas turbine engines. Only one of these engines was in the locomotive, with the other three were housed in their own separate cars. It retained the hub motor system from previous overland trains as well, meaning all 54 wheels on the vehicle were powered.
But unlike on LeTourneau’s other land trains, the trailers were also steerable, so the turning radius (which was formerly something like a quarter mile) was now much tighter, as seen in the image above.
The locomotive itself was massive at over 30 feet tall, but its size belied the fact that the smaller gas turbine engines allowed LeTourneau to add living quarters as well. The inside of the locomotive could sleep six and had a complete galley and bathroom. The train’s total length? 570 feet—nearly two football fields. And due to the train’s modular construction, the max length was theoretically infinite. As many power cars as were necessary could be added, along with the fuel to keep them running.
The TC-497 was tested by the Army in 1962 at the Yuma Proving Grounds in Arizona. The results were once again impressive—but so were simultaneous advances in heavy-lift helicopters like the Sikorsky CH-54 Tarhe, a fleet of which could accomplish what the TC-497 promised with a fraction of the time and effort. The time of solving a problem like remote logistics with a massive, almost cartoonish machine like an overland train was over.
In the end, the TC-497 was also abandoned. It sat intact in Arizona for almost a decade before its trailers were scrapped; today only the cab survives, still baking in the desert sun and collecting dust. An unfitting end to one of the largest land vehicles ever made.
Custom Fasteners Heavy Equipment Manufacturers Custom Bolts and Fasteners for Construction Equipment Manufacturing
Rush and emergency work have been in our DNA for a long time. The supply chain delivering the world’s goods can be interrupted, as we are seeing during the Covid-19 pandemic. Chicago Nut & Bolt has been keeping manufacturing lines running and products shipping for a long time. We can accommodate emergency and rush custom orders overnight or within a few hours.
As soon as our CNB representative or engineer receives your request and specifications though fax or email, pricing as well as delivery information is sent within minutes. The person who takes your order tracks the entire production schedule from production to packaging and final shipment. Finding a supplier that will produce your custom part is hard, but we are a company that can have your part ready just when you need it.
The Department of Homeland Security has deemed that Chicago Nut & Bolt falls within the Critical Manufacturing Infrastructure Sector. As a business which falls within these guidelines, we’ll continue to operate despite any Nationally or State ordered quarantine.
We qualify under several of the designated categories, as we support the following categories: Earth moving, Mining, Agricultural, and Construction Equipment / Locomotive, Railroads & Transit Cars, and Rail Track Equipment.
At this time we will continue normal business hours.
Here’s an interesting article regarding the use of custom marine fasteners in boats fighting the Australian fires. We hope and pray for success for our Aussie friends.
1.27.2020 See Original Article >
Putting out fires depends on two things. Firstly, the capability of the fire fighting equipment and the second is the volume of water available to douse the fire!
These land base firefighters are testing Aussie’s Sea Skipper on estuary seawater on Victoria’s coastline. Loads of flow, high pressure, and lightweight convenience.
Fires at sea are a massive problem with the capability of the equipment available being a key factor. Certainly, there is no issue with availability of water. It’s only about the equipment being lightweight enough to be able to move and being seawater compatible!
One Australian company has moved towards solving this issue. Australian Pump, based in Sydney, has developed a range of high pressure, seawater compatible fire pumps. Called the ‘Sea Skipper’ range, the pumps star is a new high pressure 3” pump powered by a Yanmar 10hp electric start diesel engine.
“The most important thing about this development is the ability of the pump to produce the high volumes of water at high pressure”, said Aussie’s Chief Engineer, John Hales.
For example, the pump can deliver 150 litres of water per minute at 80 metres head (105 psi). The pump can also be used as a salvage pump with flows of up to 450 lpm at 20 metres head.
Self priming in design, the 3” twin impeller pump owes its unique capacity to the pump’s hydraulics. “When we designed this pump, we started out with a 3” high volume design and then worked on changing the configuration on the internals into a high pressure performance as well”, said Hales.
The machine’s compatibility to saltwater is a simple solution. Impellers and volutes are manufactured from bronze, whilst the body of the pump and other key components are marine grade aluminium, coated with a seawater resistant epoxy coating both inside and out. The pump also is fitted with a sacrificial anode and stainless steel fasteners throughout.
“For some Navies of the world, we build these with stainless steel frames but the standard is a heavy duty galvanised frame with sub base and anti-vibration mounts”, said Hales. The inlet and outlet are 3” BSP male threads compatible with Camlocks or Storz adaptors.
Designed originally for the Royal Australian Navy, these pumps are now being used by firefighters in Australia’s terrible horrific bushfire season over the Christmas period.
“Firefighters keep running out of water when they’re trying to douse bushfires but, if they approach it from estuaries or even from the sea, from a trawler, pleasure boat or barge, they’re able to perform in a very competent manner. There’s only three things that count in a fire at sea, that’s capability, capability, capability.”, said Hales.
“Having pumps that are too heavy to move around or not able to perform is a waste of time and money. Pumps that are designed for fresh water instead of seawater also will never go the distance”, he said.
Part 1: A Fastener-Ating Look At The Bolts And Studs That Hold Your Engine Together—We’d Really Be Screwed Without Them!
Bolts, nuts, and washers: They’re what keeps your engine, drivetrain, chassis—heck, the entire car—together. Fasteners are the linchpin for a successful build—but how much attention do you really pay to them? Sure, we want our nuts and bolts to look pretty and not rust, but they’re much more than just another pretty face! Failure of a single critical engine or chassis fastener can cost you tens of thousands of bucks, due to a destroyed engine, or even an entire car. Yet with proper selection and installation practices, you can virtually eliminate fastener failure. Over the next few months, we’re going to take a granular look at today’s fastener technology with the help of Chris Raschke and the Automotive Racing Products (ARP) crew. Unless you’ve been living in a cave the last 20 years, you know that the good folks at ARP have risen to become the dominant force in supplying bulletproof fasteners for just about every hot rod and motorsport application. In this installment, we’ll look at fasteners retained primarily in tension, concentrating on those used to hold your engine together. What are their unique materials and characteristics, how are they made, and how do you properly install them? Go to Original Article >