A leadscrew known as a power screw or translation screw, is a screw used as a linkage in a machine, to translate turning motion into linear motion. Because of the large area of sliding contact between their male and female members, screw threads have larger frictional energy losses compared to other linkages, they are not used to carry high power, but more for intermittent use in low power actuator and positioner mechanisms. Common applications are linear actuators, machine slides, vises and jacks. Leadscrews are manufactured in the same way as other thread forms. A lead screw is sometimes used with a split nut called half nut which allows the nut to be disengaged from the threads and moved axially, independently of the screw's rotation, when needed. Power screws are classified by the geometry of their thread. V-threads are less suitable for leadscrews than others such as ACME because they have more friction between the threads, their threads are designed to induce this friction to keep the fastener from loosening.
Leadscrews, on the other hand, are designed to minimize friction. Therefore, in most commercial and industrial use, V-threads are avoided for leadscrew use. V-threads are sometimes used as leadscrews, for example on microlathes and micromills. Square threads are named after their square geometry, they are the most efficient, having the least friction, so they are used for screws that carry high power. But they are the most difficult to machine, are thus the most expensive. Acme threads have a 29° thread angle, easier to machine than square threads, they are not as efficient as square threads, due to the increased friction induced by the thread angle. ACME Threads are also stronger than square threads due to their trapezoidal thread profile, which provides greater load-bearing capabilities. Buttress threads are of a triangular shape; these are used. They are easier to manufacture; the advantages of a leadscrew are: Large load carrying capability Compact Simple to design Easy to manufacture. Due to the low efficiency they cannot be used in continuous power transmission applications.
They have a high degree of friction on the threads, which can wear the threads out quickly. For square threads, the nut must be replaced. Alternatives to actuation by leadscrew include: Ball screws and roller screws Fluid power Gear trains Electromagnetic actuation Piezoelectric actuation The torque required to lift or lower a load can be calculated by "unwrapping" one revolution of a thread; this is most described for a square or buttress thread as the thread angle is 0 and has no bearing on the calculations. The unwrapped thread forms a right angle triangle where the base is π d m long and the height is the lead; the force of the load is directed downward, the normal force is perpendicular to the hypotenuse of the triangle, the frictional force is directed in the opposite direction of the direction of motion, an imaginary "effort" force is acting horizontally in the direction opposite the direction of the frictional force. Using this free-body diagram the torque required to lift or lower a load can be calculated: T r a i s e = F d m 2 = F d m 2 tan T l o w e r = F d m 2 = F d m 2 tan where T = torque F = load on the screw dm = mean diameter μ = coefficient of friction l = lead ϕ = angle of friction λ = lead angleBased on the Tlower equation it can
Gunpowder known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur and potassium nitrate; the sulfur and charcoal act as fuels. Because of its incendiary properties and the amount of heat and gas volume that it generates, gunpowder has been used as a propellant in firearms, artillery and fireworks, as a blasting powder in quarrying and road building. Gunpowder was invented in 9th-century China and spread throughout most parts of Eurasia by the end of the 13th century. Developed by the Taoists for medicinal purposes, gunpowder was first used for warfare about 1000 AD. Gunpowder is classified as a low explosive because of its slow decomposition rate and low brisance. Low explosives deflagrate at subsonic speeds, whereas high explosives detonate, producing a supersonic wave. Ignition of gunpowder packed behind a projectile generates enough pressure to force the shot from the muzzle at high speed, but not enough force to rupture the gun barrel.
Gunpowder thus makes a good propellant, but is less suitable for shattering rock or fortifications with its low-yield explosive power. However, by transferring enough energy a bombardier may wear down an opponent's fortified defenses. Gunpowder was used to fill fused artillery shells until the second half of the 19th century, when the first high explosives were put into use. Gunpowder is no longer used in modern weapons, nor is it used for industrial purposes, due to its inefficient cost compared to newer alternatives such as dynamite and ammonium nitrate/fuel oil. Today gunpowder firearms are limited to hunting, target shooting, bulletless historical reenactments. Based on a 9th-century Taoist text, the invention of gunpowder by Chinese alchemists was an accidental byproduct from experiments seeking to create the elixir of life; this experimental medicine origin of gunpowder is reflected in its Chinese name huoyao, which means "fire medicine". The first military applications of gunpowder were developed around 1000 AD.
The earliest chemical formula for gunpowder appeared in the 11th century Song dynasty text, Wujing Zongyao, however gunpowder had been used for fire arrows since at least the 10th century. In the following centuries various gunpowder weapons such as bombs, fire lances, the gun appeared in China. Saltpeter was known to the Chinese by the mid-1st century AD and was produced in the provinces of Sichuan and Shandong. There is strong evidence of the use of sulfur in various medicinal combinations. A Chinese alchemical text dated 492 noted saltpeter burnt with a purple flame, providing a practical and reliable means of distinguishing it from other inorganic salts, thus enabling alchemists to evaluate and compare purification techniques; the first reference to the incendiary properties of such mixtures is the passage of the Zhenyuan miaodao yaolüe, a Taoist text tentatively dated to the mid-9th century: "Some have heated together sulfur and saltpeter with honey. The Chinese word for "gunpowder" is Chinese: 火药/火藥.
In the following centuries a variety of gunpowder weapons such as rockets and land mines appeared before the first metal barrel firearms were invented. Explosive weapons such as bombs have been discovered in a shipwreck off the shore of Japan dated from 1281, during the Mongol invasions of Japan; the Chinese Wujing Zongyao, written by Zeng Gongliang between 1040 and 1044, provides encyclopedia references to a variety of mixtures that included petrochemicals—as well as garlic and honey. A slow match for flame throwing mechanisms using the siphon principle and for fireworks and rockets is mentioned; the mixture formulas in this book do not contain enough saltpeter to create an explosive however. The Essentials was however written by a Song dynasty court bureaucrat, there is little evidence that it had any immediate impact on warfare. However, by 1083 the Song court was producing hundreds of thousands of fire arrows for their garrisons. Bombs and the first proto-guns, known as "fire lances", became prominent during the 12th century and were used by the Song during the Jin-Song Wars.
Fire lances were first recorded to have been used at the Siege of De'an in 1132 by Song forces against the Jin. In the early 13th century the Jin utilized iron-casing bombs. Projectiles were added to fire lances, re-usable fire lance barrels were developed, first out of hardened paper, metal. By 1257 some fire lances were firing wads of bullets. In the late 13th century metal fire lances became'eruptors', proto-cannons firing co-viative projectiles, by 1287 at the latest, had become true guns, the hand cannon; the earliest Western accounts of gunpowder appear in texts written by English philosopher Roger Bacon in the 13th century. Several sources men
Marine steam engine
A marine steam engine is a steam engine, used to power a ship or boat. This article deals with marine steam engines of the reciprocating type, which were in use from the inception of the steamboat in the early 19th century to their last years of large-scale manufacture during World War II. Reciprocating steam engines were progressively replaced in marine applications during the 20th century by steam turbines and marine diesel engines; the first commercially successful steam engine was developed by Thomas Newcomen in 1712. The steam engine improvements brought forth by James Watt in the half of the 18th century improved steam engine efficiency and allowed more compact engine arrangements. Successful adaptation of the steam engine to marine applications in England would have to wait until a century after Newcomen, when Scottish engineer William Symington built the world's "first practical steamboat", the Charlotte Dundas, in 1802. In 1807, the American Robert Fulton built the world's first commercially successful steamboat known as the North River Steamboat, powered by a Watt engine.
Following Fulton's success, steamboat technology developed on both sides of the Atlantic. Steamboats had a short range and were not seaworthy due to their weight, low power, tendency to break down, but they were employed along rivers and canals, for short journeys along the coast; the first successful transatlantic crossing by a steamship occurred in 1819 when Savannah sailed from Savannah, Georgia to Liverpool, England. The first steamship to make regular transatlantic crossings was the sidewheel steamer Great Western in 1838; as the 19th century progressed, marine steam engines and steamship technology developed alongside each other. Paddle propulsion gave way to the screw propeller, the introduction of iron and steel hulls to replace the traditional wooden hull allowed ships to grow larger, necessitating steam power plants that were complex and powerful. A wide variety of reciprocating marine steam engines were developed over the course of the 19th century; the two main methods of classifying such engines are by connection mechanism and cylinder technology.
Most early marine engines had the same cylinder technology but a number of different methods of supplying power to the crankshaft were in use. Thus, early marine engines are classified according to their connection mechanism; some common connection mechanisms were side-lever, walking beam and direct-acting. However, steam engines can be classified according to cylinder technology. One can therefore find examples of engines classified under both methods. An engine can be a compound walking beam type, compound being the cylinder technology, walking beam being the connection method. Over time, as most engines became direct-acting but cylinder technologies grew more complex, people began to classify engines according to cylinder technology. More encountered marine steam engine types are listed in the following sections. Note that not all these terms are exclusive to marine applications; the side-lever engine was the first type of steam engine adopted for marine use in Europe. In the early years of steam navigation, the side-lever was the most common type of marine engine for inland waterway and coastal service in Europe, it remained for many years the preferred engine for oceangoing service on both sides of the Atlantic.
The side-lever was an adaptation of the earliest form of the beam engine. The typical side-lever engine had a pair of heavy horizontal iron beams, known as side levers, that connected in the centre to the bottom of the engine with a pin; this connection allowed a limited arc for the levers to pivot in. These levers extended, on the cylinder side, to each side of the bottom of the vertical engine cylinder. A piston rod, connected vertically to the piston, extended out of the top of the cylinder; this rod attached to a horizontal crosshead, connected at each end to vertical rods. These rods connected down to the levers on each side of the cylinder; this formed the connection of the levers to the piston on the cylinder side of the engine. The other side of the levers were connected to each other with a horizontal crosstail; this crosstail in turn connected to and operated a single connecting rod, which turned the crankshaft. The rotation of the crankshaft was driven by the levers—which, at the cylinder side, were driven by the piston's vertical oscillation.
The main disadvantage of the side-lever engine was that it was heavy. For inland waterway and coastal service and more efficient designs soon replaced it, it remained the dominant engine type for oceangoing service through much of the first half of the 19th century however, due to its low centre of gravity, which gave ships more stability in heavy seas. It was a common early engine type for warships, since its low height made it less susceptible to battle damage. From the first Royal Navy steam vessel in 1820 until 1840, 70 steam vessels entered service, the majority with side-lever engines, using boilers set to 4psi maximum pressure; the low steam pressures dictated the large cylinder sizes for the side-lever engines, though the effective pressure on the piston was the difference between the boiler pressure and the vacuum in the condenser. The side-lever engine was not suitable for driving screw propellers; the last ship built for transatlantic service that had a side-lever engine was the Cunard Line's pa
London is the capital and largest city of both England and the United Kingdom. Standing on the River Thames in the south-east of England, at the head of its 50-mile estuary leading to the North Sea, London has been a major settlement for two millennia. Londinium was founded by the Romans; the City of London, London's ancient core − an area of just 1.12 square miles and colloquially known as the Square Mile − retains boundaries that follow its medieval limits. The City of Westminster is an Inner London borough holding city status. Greater London is governed by the Mayor of the London Assembly. London is considered to be one of the world's most important global cities and has been termed the world's most powerful, most desirable, most influential, most visited, most expensive, sustainable, most investment friendly, most popular for work, the most vegetarian friendly city in the world. London exerts a considerable impact upon the arts, education, fashion, healthcare, professional services and development, tourism and transportation.
London ranks 26 out of 300 major cities for economic performance. It is one of the largest financial centres and has either the fifth or sixth largest metropolitan area GDP, it is the most-visited city as measured by international arrivals and has the busiest city airport system as measured by passenger traffic. It is the leading investment destination, hosting more international retailers and ultra high-net-worth individuals than any other city. London's universities form the largest concentration of higher education institutes in Europe. In 2012, London became the first city to have hosted three modern Summer Olympic Games. London has a diverse range of people and cultures, more than 300 languages are spoken in the region, its estimated mid-2016 municipal population was 8,787,892, the most populous of any city in the European Union and accounting for 13.4% of the UK population. London's urban area is the second most populous in the EU, after Paris, with 9,787,426 inhabitants at the 2011 census.
The population within the London commuter belt is the most populous in the EU with 14,040,163 inhabitants in 2016. London was the world's most populous city from c. 1831 to 1925. London contains four World Heritage Sites: the Tower of London. Other landmarks include Buckingham Palace, the London Eye, Piccadilly Circus, St Paul's Cathedral, Tower Bridge, Trafalgar Square and The Shard. London has numerous museums, galleries and sporting events; these include the British Museum, National Gallery, Natural History Museum, Tate Modern, British Library and West End theatres. The London Underground is the oldest underground railway network in the world. "London" is an ancient name, attested in the first century AD in the Latinised form Londinium. Over the years, the name has attracted many mythicising explanations; the earliest attested appears in Geoffrey of Monmouth's Historia Regum Britanniae, written around 1136. This had it that the name originated from a supposed King Lud, who had taken over the city and named it Kaerlud.
Modern scientific analyses of the name must account for the origins of the different forms found in early sources Latin, Old English, Welsh, with reference to the known developments over time of sounds in those different languages. It is agreed; this was adapted into Latin as Londinium and borrowed into Old English, the ancestor-language of English. The toponymy of the Common Brythonic form is much debated. A prominent explanation was Richard Coates's 1998 argument that the name derived from pre-Celtic Old European *lowonida, meaning "river too wide to ford". Coates suggested that this was a name given to the part of the River Thames which flows through London. However, most work has accepted a Celtic origin for the name, recent studies have favoured an explanation along the lines of a Celtic derivative of a proto-Indo-European root *lendh-, combined with the Celtic suffix *-injo- or *-onjo-. Peter Schrijver has suggested, on these grounds, that the name meant'place that floods'; until 1889, the name "London" applied to the City of London, but since it has referred to the County of London and Greater London.
"London" is sometimes written informally as "LDN". In 1993, the remains of a Bronze Age bridge were found on the south foreshore, upstream of Vauxhall Bridge; this bridge either reached a now lost island in it. Two of those timbers were radiocarbon dated to between 1750 BC and 1285 BC. In 2010 the foundations of a large timber structure, dated to between 4800 BC and 4500 BC, were found on the Thames's south foreshore, downstream of Vauxhall Bridge; the function of the mesolithic structure is not known. Both structures are on the south bank. Although there is evidence of scattered Brythonic settlements in the area, the first major settlement was founded by the Romans about four years after the invasion
A screw is a type of fastener, in some ways similar to a bolt made of metal, characterized by a helical ridge, known as a male thread. Screws are used to fasten materials by digging in and wedging into a material when turned, while the thread cuts grooves in the fastened material that may help pull fastened materials together and prevent pull-out. There are many screws for a variety of materials. A screw is a combination of simple machines—it is in essence an inclined plane wrapped around a central shaft, but the inclined plane comes to a sharp edge around the outside, which acts a wedge as it pushes into the fastened material, the shaft and helix form a wedge in the form of the point; some screw threads are designed to mate with a complementary thread, known as a female thread in the form of a nut, or object that has the internal thread formed into it. Other screw threads are designed to cut a helical groove in a softer material as the screw is inserted; the most common uses of screws are to hold objects together and to position objects.
A screw will have a head on one end that contains a specially formed shape that allows it to be turned, or driven, with a tool. Common tools for driving screws include wrenches; the head is larger than the body of the screw, which keeps the screw from being driven deeper than the length of the screw and to provide a bearing surface. There are exceptions; the cylindrical portion of the screw from the underside of the head to the tip is known as the shank. The distance between each thread is called the "pitch"; the majority of screws are tightened by clockwise rotation, termed a right-hand thread. If the fingers of the right hand are curled around a right-hand thread, it will move in the direction of the thumb when turned in the same direction as the fingers are curled. Screws with left-hand threads are used in exceptional cases, where loads would tend to loosen a right handed fastener, or when non-interchangeability with right-hand fasteners is required. For example, when the screw will be subject to counterclockwise torque, a left-hand-threaded screw would be an appropriate choice.
The left side pedal of a bicycle has a left-hand thread. More screw may mean any helical device, such as a clamp, a micrometer, a ship's propeller, or an Archimedes' screw water pump. There is no universally accepted distinction between a bolt. A simple distinction, true, although not always, is that a bolt passes through a substrate and takes a nut on the other side, whereas a screw takes no nut because it threads directly into the substrate. So, as a general rule, when buying a packet of "screws" nuts would not be expected to be included, but bolts are sold with matching nuts. Part of the confusion over this is due to regional or dialectical differences. Machinery's Handbook describes the distinction as follows: A bolt is an externally threaded fastener designed for insertion through holes in assembled parts, is intended to be tightened or released by torquing a nut. A screw is an externally threaded fastener capable of being inserted into holes in assembled parts, of mating with a preformed internal thread or forming its own thread, of being tightened or released by torquing the head.
An externally threaded fastener, prevented from being turned during assembly and which can be tightened or released only by torquing a nut is a bolt. An externally threaded fastener that has thread form which prohibits assembly with a nut having a straight thread of multiple pitch length is a screw; this distinction is consistent with ASME B18.2.1 and some dictionary definitions for bolt. The issue of what is a screw and what is a bolt is not resolved with Machinery's Handbook distinction, because of confounding terms, the ambiguous nature of some parts of the distinction, usage variations; some of these issues are discussed below: Early wood screws were made by hand, with a series of files and other cutting tools, these can be spotted by noting the irregular spacing and shape of the threads, as well as file marks remaining on the head of the screw and in the area between threads. Many of these screws had a blunt end lacking the sharp tapered point on nearly all modern wood screws. Lathes were used to manufacture wood screws, with the earliest patent being recorded in 1760 in England.
During the 1850s swaging tools were developed to provide a more consistent thread. Screws made with these tools have rounded valleys with rough threads; some wood screws were made with cutting dies as early as the late 1700s. Once screw turning machines were in common use, most commercially available wood screws were produced with this method; these cut wood screws are invariably tapered, when the tapered shank is not obvious, they can b
Kent is a county in South East England and one of the home counties. It borders Surrey to the west and East Sussex to the south-west; the county shares borders with Essex along the estuary of the River Thames, with the French department of Pas-de-Calais through the Channel Tunnel. The county town is Maidstone. Canterbury Cathedral in Kent has been the seat of the Archbishop of Canterbury, leader of the Church of England, since the Reformation. Prior to that it was built by Catholics, dating back to the conversion of England to Catholicism by Saint Augustine that began in the 6th century. Before the English Reformation the cathedral was part of a Benedictine monastic community known as Christ Church, Canterbury, as well as being the seat of the Catholic Archbishop of Canterbury; the last Catholic Archbishop of Canterbury was Reginald Pole. Rochester Cathedral is in Kent, in Medway, it is the second-oldest cathedral in England, with Canterbury Cathedral being the oldest. Between London and the Strait of Dover, which separates it from mainland Europe, Kent has seen both diplomacy and conflict, ranging from the Leeds Castle peace talks of 1978 and 2004 to the Battle of Britain in World War II.
England relied on the county's ports to provide warships through much of its history. France can be seen in fine weather from Folkestone and the White Cliffs of Dover. Hills in the form of the North Downs and the Greensand Ridge span the length of the county and in the series of valleys in between and to the south are most of the county's 26 castles; because of its relative abundance of fruit-growing and hop gardens, Kent is known as "The Garden of England". Kent's economy is diversified. In northwest Kent industries include extraction of aggregate building materials and scientific research. Coal mining has played its part in Kent's industrial heritage. Large parts of Kent are within the London commuter belt and its strong transport connections to the capital and the nearby continent makes Kent a high-income county. Twenty-eight per cent of the county forms part of two Areas of Outstanding Natural Beauty: the North Downs and The High Weald; the name Kent is believed to be of British Celtic origin and was known in Old English as Cent, Cent lond, Centrice.
In Latin sources Kent is mentioned as Canticum. The meaning is explained by some researchers as "coastal district," or "corner-land, land on the edge". If so, the name could be etymologically related to the placename Cantabria a Celtiberian-speaking coastal region in pre-Roman Iberia, today a province of Spain; the area has been occupied since the Palaeolithic era, as attested by finds from the quarries at Swanscombe. The Medway megaliths were built during the Neolithic era. There is a rich sequence of Bronze Age, Iron Age, Roman era occupation, as indicated by finds and features such as the Ringlemere gold cup and the Roman villas of the Darent valley; the modern name of Kent is derived from the Brythonic word kantos meaning "rim" or "border", or from a homonymous word kanto "horn, hook". This describes the eastern part of the current county area as coastal district. Julius Caesar had described the area as um, or home of the Cantiaci in 51 BC; the extreme west of the modern county was by the time of Roman Britain occupied by Iron Age tribes, known as the Regnenses.
Caesar wrote that the people of Kent are'by far the most civilised inhabitants of Britain'. East Kent became a kingdom of the Jutes during the 5th century and was known as Cantia from about 730 and recorded as Cent in 835; the early medieval inhabitants of the county were known as the Kent people. These people regarded the city of Canterbury as their capital. In 597, Pope Gregory I appointed the religious missionary as the first Archbishop of Canterbury. In the previous year, Augustine converted the pagan King Æthelberht of Kent to Christianity; the Diocese of Canterbury became England's first Episcopal See with first cathedral and has since remained England's centre of Christianity. The second designated English cathedral was in Kent at Rochester Cathedral. In the 11th century, the people of Kent adopted the motto Invicta, meaning "undefeated" or "unconquered"; this naming followed the invasion of Britain by William of Normandy. The Kent people's continued resistance against the Normans led to Kent's designation as a semi-autonomous county palatine in 1067.
Under the nominal rule of William's half-brother Odo of Bayeux, the county was granted similar powers to those granted in the areas bordering Wales and Scotland. Kent was traditionally partitioned into East and West Kent, into lathes and hundreds; the traditional border of East and West Kent was the Medway. Men and women from east of the Medway are Men of Kent, those from the west are Kentishmen or Kentish Maids. During the medieval and early modern period, Kent played a major role in several of England's most notable rebellions, including the Peasants' Revolt of 1381, led by Wat Tyler,Jack Cade's Kent rebellion of 1450, Wyatt's Rebellion of 1554 against Queen Mary I; the Royal Navy first used the River Medway in 1547. By the reign of Elizabeth I a small dockyard had been established at Chatham. By 1618, storehouses, a ropewalk, a drydock, houses for officials had
James Hall Nasmyth was a Scottish engineer, philosopher and inventor famous for his development of the steam hammer. He was the co-founder of Nasmyth and Company manufacturers of machine tools, he retired at the age of 48, moved to Penshurst, Kent where he developed his hobbies of astronomy and photography. James Nasmyth was born at 47 York Place, Edinburgh where his father Alexander Nasmyth was a landscape and portrait painter. One of Alexander's hobbies was mechanics and he employed nearly all his spare time in his workshop where he encouraged his youngest son to work with him in all sorts of materials. James was sent to the Royal High School where he had as a friend, Jimmy Patterson, the son of a local iron founder. Being interested in mechanics he spent much of his time at the foundry and there he learned to work and turn in wood, brass and steel. In 1820 he left the High School and again made great use of his father's workshop where at the age of 17, he made his first steam engine. From 1821 to 1826, Nasmyth attended the Edinburgh School of Arts.
In 1828 he made a complete steam carriage, capable of running a mile carrying 8 passengers. This accomplishment increased his desire to become a mechanical engineer, he had resolved to get employment there. Nasmyth therefore decided instead to show Maudslay examples of his skills and produced a complete working model of a high-pressure steam engine, creating the working drawings and constructing the components himself. In May 1829 Nasmyth visited Maudslay in London, after showing him his work was engaged as an assistant workman at 10 shillings a week. Maudslay died two years whereupon Nasmyth was taken on by Maudslay's partner as a draughtsman; when Nasmyth was 23 years old, having saved the sum of £69, he decided to set up in business on his own. He rented a factory flat 130 feet long by 27 feet wide at an old Cotton Mill on Dale Street, Manchester; the combination of massive castings and a wooden floor was not an ideal one, after an accident involving one end of an engine beam crashing through the floor into a glass cutters flat below he soon relocated.
He moved to Patricroft, an area of the town of Eccles, where in August 1836, he and his business partner Holbrook Gaskell opened the Bridgewater Foundry, where they traded as Nasmyth and Company. The premises were constructed adjacent to the Liverpool and Manchester Railway and the Bridgewater Canal. In March 1838 James was making a journey by coach from Sheffield to York in a snowstorm, when he spied some ironwork furnaces in the distance; the coachman informed him that they were managed by a Mr. Hartop, one of his customers, he got off the coach and headed for the furnaces through the deep snow. He found Mr. Hartop at his house, was invited to stay the night and visit the works the next day; that evening he met Hartop's family and was smitten by his 21-year-old daughter, Anne. A decisive man, the next day he told her of his feelings and intentions, received "in the best spirit that I could desire." He communicated the same to her parents, told them his prospects, so became betrothed in the same day.
They were married two years on 16 June 1840 in Wentworth. Up to 1843, Gaskell & Co. concentrated on producing a wide range of machine tools in large numbers. By 1856, Nasmyth had built 236 shaping machines. In 1840 he began to receive orders from the newly opened railways which were beginning to cover the country, for locomotives, his connection with the Great Western Railway whose famous steamship SS Great Western had been so successful in voyages between Bristol and New York, led to him being asked to make some machine tools of unusual size and power which were required for the construction of the engines of their next and bigger ship SS Great Britain. In 1837 the Great Western Steam Company was experiencing many problems forging the paddle shaft of the SS Great Britain. What am I to do? Nasmyth thought the matter over and seeing the obvious defects of the tilt-hammer sketched out his idea for the first steam hammer, he kept his ideas for new devices in drawings, in a "Scheme Book" which he showed to his foreign customers.
Nasmyth made a sketch of his steam hammer design dated 24 November 1839, but the immediate need disappeared when the practicality of screw propellers was demonstrated and the Great Britain was converted to that design. The French engineer François Bourdon came up with the similar idea of what he called a "Pilon" in 1839 and made detailed drawings of his design, which he showed to all engineers who visited the works at Le Creusot owned by the brothers Adolphe and Eugène Schneider. However, the Schneiders hesitated to build Bourdon's radical new machine. Bourdon and Eugène Schneider visited the Nasmyth works in England in the middle of 1840, where they were shown Nasmyth's sketch; this confirmed the feasibility of the concept to Schneider. In 1840 Bourdon built the first steam hammer in the world at the Schneid