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75-610: In the early-1950s, Yamaha had to replace its musical instrument factories as they were severely damaged during the war. Yamaha was also facing the industrial conversion of factory machine tools that had been used during the war for the production of fuel tanks, wing parts, and propellers for aircraft of the Imperial Japanese Navy , such as the Mitsubishi A6M Zero fighter. As in European countries,

150-458: A Glasgow manufacturer to turn his award-winning design into a product. The manufacturer coined the name Strida , and in 1987 the bicycle began rolling off the production line. In 2002 production was moved to Taiwanese manufacturer Ming Cycle in order to meet increased demand, and as of 2007, Ming Cycle fully owned the Strida brand and intellectual property rights. iXi bicycles, distributed in

225-452: A drill machine might contain a magazine with a variety of drill bits for producing holes of various sizes. Previously, either machine operators would usually have to manually change the bit or move the work piece to another station to perform these different operations. The next logical step was to combine several different machine tools together, all under computer control. These are known as machining centers , and have dramatically changed

300-539: A folding bicycle as part of his graduate studies in an Industrial Design Engineering (IDE) program. The program was run jointly by Imperial College and the Royal College of Art in London. He collaborated with a design engineer from Gates Corporation to outfit his bicycle with a belt, rather than a chain. When his project was complete, Sanders chose entrepreneur and former Greg Norman manager James Marshall and

375-514: A retrofuturistic concept motorcycle from Yamaha, designed along the lines of the 1955 YA-1. The Y125 Moegi is powered by an air-cooled 125cc single-cylinder engine (although this new engine is an SOHC four-stroke ) sitting in an aluminum frame for a claimed weight of just 80 kilograms (180 pounds), which makes the Moegi ( 萌黄 , "Light Green") significantly lighter than the YA-1 was. The Moegi uses

450-608: A "ball and socket" concave-concave and convex-convex fit, as this mechanical fit, like two perfect planes, can slide over each other and reveal no high spots. The rubbing and marking are repeated after rotating 2 relative to 1 by 90 degrees to eliminate concave-convex "potato-chip" curvature. Next, plate number 3 is compared and scraped to conform to plate number 1 in the same two trials. In this manner plates number 2 and 3 would be identical. Next plates number 2 and 3 would be checked against each other to determine what condition existed, either both plates were "balls" or "sockets" or "chips" or

525-418: A Gates-compatible fixed-gear cog designed by Phil Wood & Co. , offering a belt-driven fixed-gear bicycle. In 2009, Wayne Lumpkin, owner of Spot Brand and best known as the founder of Avid , designed a belt system called CenterTrack. In 2010, Gates Corporation acquired a patent from Lumpkin for CenterTrack, a new belt-and-pulley design that improves on the initial Carbon Drive System design. CenterTrack

600-421: A combination. These would then be scraped until no high spots existed and then compared to plate number 1. Repeating this process of comparing and scraping the three plates could produce plane surfaces accurate to within millionths of an inch (the thickness of the marking medium). The traditional method of producing the surface gages used an abrasive powder rubbed between the plates to remove the high spots, but it

675-515: A handful of major industries that most spurred machine tool development. In order of historical emergence, they have been firearms (small arms and artillery ); clocks ; textile machinery; steam engines ( stationary , marine , rail , and otherwise ) (the story of how Watt 's need for an accurate cylinder spurred Boulton's boring machine is discussed by Roe ); sewing machines ; bicycles ; automobiles ; and aircraft . Others could be included in this list as well, but they tend to be connected with

750-495: A lathe with direct mechanical control of the cutting tool's path are of a screw-cutting lathe dating to about 1483. This lathe "produced screw threads out of wood and employed a true compound slide rest". The mechanical toolpath guidance grew out of various root concepts: Abstractly programmable toolpath guidance began with mechanical solutions, such as in musical box cams and Jacquard looms . The convergence of programmable mechanical control with machine tool toolpath control

825-689: A low-maintenance belt final drive and rides on 20-inch wheels. The modified engine is based on the power plant of the YBR125 and Yamaha claims a fuel consumption of 80 km/L (230 mpg ‑imp ; 190 mpg ‑US ) for the Y125 Moegi, making it efficient personal transportation in urban environments. Machine tool A machine tool is a machine for handling or machining metal or other rigid materials, usually by cutting, boring , grinding , shearing, or other forms of deformations. Machine tools employ some sort of tool that does

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900-468: A machine tool as "any machine operating by other than hand power which employs a tool to work on metal". The narrowest colloquial sense of the term reserves it only for machines that perform metal cutting—in other words, the many kinds of [conventional] machining and grinding . These processes are a type of deformation that produces swarf . However, economists use a slightly broader sense that also includes metal deformation of other types that squeeze

975-400: A machine tool as well as expressing its fundamental structure in the following way: imagine a lathe spending a cylinder on a horizontal axis with a tool ready to cut a face on that cylinder in some preparatory moment. What the operator of such a lathe would do is lock the x-axis on the carriage of the lathe establishing a new vector condition with a zero in the x slide position for the tool. Then

1050-418: A machine tool is, is a very simple answer but it is highly technical and is unrelated to the history of machine tools. Preceding, there is an answer for what machine tools are. We may consider what they do also. Machine tools produce finished surfaces. They may produce any finish from an arbitrary degree of very rough work to a specular optical grade finish the improvement of which is moot. Machine tools produce

1125-431: A machine tool, toolpaths that no human muscle could constrain can be constrained; and toolpaths that are technically possible with freehand methods, but would require tremendous time and skill to execute, can instead be executed quickly and easily, even by people with little freehand talent (because the machine takes care of it). The latter aspect of machine tools is often referred to by historians of bytechnology as "building

1200-439: A male college graduate's starting salary was ¥10,780 on average). Thanks to the popularity of the YA-1, a YB-1 model with a 4 cc larger displacement (allowing the engine to run slower) was produced later in 1955. A genuine successor to the YA-1, the 175 cc YC-1 was being produced by April 1956. The YA-1 was the first Japanese motorcycle to take advantage of a primary starting mechanism. Previously, motorcycles with

1275-401: A non-primary starting system used the transmission input shaft and clutch hub to connect the kick-start lever to crankshaft . It was thus necessary for the rider to first put the transmission into neutral, and then to engage the clutch before the starting the engine by pushing down on the kick-start lever. With its primary starting system, the YA-1 engine is equipped with a mechanism in which

1350-403: A preparatory moment before a tool makes contact with a work piece, or maybe an engaged moment during which contact with work and tool requires an input of rather large amounts of power to get work done which is why machine tools are large and heavy and stiff. Since what these vectors describe our instant moments of degrees of freedom the vector structure is capable of expressing the changing mode of

1425-431: A survey by market research firm Gardner Research. The largest producer of machine tools was China with $ 23.8 billion of production followed by Germany and Japan at neck and neck with $ 12.9 billion and $ 12.88 billion respectively. South Korea and Italy rounded out the top 5 producers with revenue of $ 5.6 billion and $ 5 billion respectively. . A biography of a machine tool builder that also contains some general history of

1500-571: A variety of sources. Human and animal power (via cranks , treadles , treadmills , or treadwheels ) were used in the past, as was water power (via water wheel ); however, following the development of high-pressure steam engines in the mid 19th century, factories increasingly used steam power. Factories also used hydraulic and pneumatic power. Many small workshops continued to use water, human and animal power until electrification after 1900. Today most machine tools are powered by electricity; hydraulic and pneumatic power are sometimes used, but this

1575-572: Is a separate tensioner pulley, which changes the travel distance of the belt. A belt drive for a bicycle was patented in the United States on April 8, 1890 by Charles D. Rice, Patent # 425,390. In 1898, Mathew Joseph Steffens of Chicago, Illinois received a patent for a rear-wheel drive electric bicycle using a driving belt attached to the periphery of the pneumatic-tired wheel. By the early 1900s, some motorcycles were using leather drive belts. The Bridgestone Picnica belt-drive bicycle

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1650-410: Is also problematic, as machine tools can be powered by people if appropriately set up, such as with a treadle (for a lathe ) or a hand lever (for a shaper ). Hand-powered shapers are clearly "the 'same thing' as shapers with electric motors except smaller", and it is trivial to power a micro lathe with a hand-cranked belt pulley instead of an electric motor. Thus one can question whether power source

1725-435: Is concentrated in about 10 countries worldwide: China, Japan, Germany, Italy, South Korea, Taiwan, Switzerland, US, Austria, Spain and a few others. Machine tool innovation continues in several public and private research centers worldwide. [A]ll the turning of the iron for the cotton machinery built by Mr. Slater was done with hand chisels or tools in lathes turned by cranks with hand power. Machine tools can be powered from

1800-654: Is designed for a clean, grease-free ride. Other notable eBike brands include Grace and Pi-Mobility. In 2012, Continental AG ’s subsidiary ContiTech introduced the CONTI® DRIVE SYSTEM for bicycles. The CDS belt drive shared the basic operation of the early 8mm Gates Carbon Drive system, but employed aramid instead of carbon fibers in its construction. The Conti CDS was designed exclusively for ‘normal use on properly laid’ roads and paths. ContiTech eventually switched to carbon belts for bicycle use, citing issues with traction using aramid fibers. The CDS belt drive

1875-507: Is more tolerant to misalignment than its predecessors. It is also lighter, 20% stronger due to a wider 11mm belt, yet has narrower pulleys, making packaging with the latest generation of internally geared hubs much easier. The company’s CDX belt is the first belt drive designed for severe off-road use on mountain bikes. In 2010, Daimler introduced the Smart eBike, a power-electric hybrid bicycle featuring Gates Carbon drive-belt system. The eBike

1950-664: Is truly a key distinguishing concept; but for economics purposes, the NBER's definition made sense, because most of the commercial value of the existence of machine tools comes about via those that are powered by electricity, hydraulics, and so on. Such are the vagaries of natural language and controlled vocabulary , both of which have their places in the business world. Forerunners of machine tools included bow drills and potter's wheels , which had existed in ancient Egypt prior to 2500 BC, and lathes , known to have existed in multiple regions of Europe since at least 1000 to 500 BC. But it

2025-427: Is uncommon. Machine tools can be operated manually, or under automatic control. Early machines used flywheels to stabilize their motion and had complex systems of gears and levers to control the machine and the piece being worked on. Soon after World War II, the numerical control (NC) machine was developed. NC machines used a series of numbers punched on paper tape or punched cards to control their motion. In

2100-641: The Industrial Revolution in England in the middle to late 1700s. Until that time, machinery was made mostly from wood, often including gearing and shafts. The increase in mechanization required more metal parts, which were usually made of cast iron or wrought iron . Cast iron could be cast in molds for larger parts, such as engine cylinders and gears, but was difficult to work with a file and could not be hammered. Red hot wrought iron could be hammered into shapes. Room temperature wrought iron

2175-429: The mass noun "machinery" encompasses them, but sometimes it is used to imply only those machines that are being excluded from the definition of "machine tool". This is why the machines in a food-processing plant, such as conveyors, mixers, vessels, dividers, and so on, may be labeled "machinery", while the machines in the factory's tool and die department are instead called "machine tools" in contradistinction. Regarding

2250-419: The 18th and 19th centuries, and even in many cases in the 20th, the builders of machine tools tended to be the same people who would then use them to produce the end products (manufactured goods). However, from these roots also evolved an industry of machine tool builders as we define them today, meaning people who specialize in building machine tools for sale to others. Historians of machine tools often focus on

2325-496: The 1930s NBER definition quoted above, one could argue that its specificity to metal is obsolete, as it is quite common today for particular lathes, milling machines, and machining centers (definitely machine tools) to work exclusively on plastic cutting jobs throughout their whole working lifespan. Thus the NBER definition above could be expanded to say "which employs a tool to work on metal or other materials of high hardness ". And its specificity to "operating by other than hand power"

Yamaha YA-1 - Misplaced Pages Continue

2400-442: The 1960s, computers were added to give even more flexibility to the process. Such machines became known as computerized numerical control (CNC) machines . NC and CNC machines could precisely repeat sequences over and over, and could produce much more complex pieces than even the most skilled tool operators. Before long, the machines could automatically change the specific cutting and shaping tools that were being used. For example,

2475-722: The 1980s; he was reflecting the sense of the term used by Houdaille itself and other firms in the industry. Many reports on machine tool export and import and similar economic topics use this broader definition. The colloquial sense implying [conventional] metal cutting is also growing obsolete because of changing technology over the decades. The many more recently developed processes labeled "machining", such as electrical discharge machining , electrochemical machining , electron beam machining , photochemical machining , and ultrasonic machining , or even plasma cutting and water jet cutting , are often performed by machines that could most logically be called machine tools. In addition, some of

2550-866: The United States by Delta Cycle Corporation , followed in 2004 with a compact design that, like Strida, featured a belt drive. Other folding-bike manufacturers that have implemented a belt drive include U.S. company Bike Friday and Netherlands-based Bernds. In 2007, Gates Corporation developed a high-modulus 8mm synchronous belt and sprocket system called the Carbon Drive System. The belt's pitch allowed for lower tension requirements to help prevent skipping. Lightweight, patent-pending sprockets have mud ports, openings under each tooth, which work to slough off debris. In 2009, an increasing number of bicycle companies, including Trek and f 8 Cycles, offered belt-driven bicycles. While builders initially focused on single-speeds and internal hubs, in early 2009 f 8 used

2625-628: The YA-1 won again in both the Light and Ultra-light classes of the Asama Highlands Race. The YA-1 soon established a reputation as a high-quality and reliable machine, which Japanese enthusiasts affectionately nicknamed the Aka-tombo ( 赤トンボ , "Red Dragonfly") for its slender shape and elegant chestnut red finish. Outstanding race performance had made the YA-1 much more desirable, in spite of its price of ¥138,000 in 1955 (for comparison,

2700-553: The abrasive material between the plates which would produce uneven removal of material from the plates. With the creation of master plane gages of such high accuracy, all critical components of machine tools (i.e., guiding surfaces such as machine ways) could then be compared against them and scraped to the desired accuracy. The first machine tools offered for sale (i.e., commercially available) were constructed by Matthew Murray in England around 1800. Others, such as Henry Maudslay , James Nasmyth , and Joseph Whitworth , soon followed

2775-495: The accuracy of machine tools can be traced to Henry Maudslay and refined by Joseph Whitworth . That Maudslay had established the manufacture and use of master plane gages in his shop (Maudslay & Field) located on Westminster Road south of the Thames River in London about 1809, was attested to by James Nasmyth who was employed by Maudslay in 1829 and Nasmyth documented their use in his autobiography. The process by which

2850-528: The bar length standards of the 19th and early 20th centuries. American production of machine tools was a critical factor in the Allies' victory in World War II. Production of machine tools tripled in the United States in the war. No war was more industrialized than World War II, and it has been written that the war was won as much by machine shops as by machine guns. The production of machine tools

2925-519: The beginning the need to grapple with high specifications, for customers with elite, rather narrow needs, especially in view of the reduced number of production potential. In January 1955, Nippon Gakki's (Japan Instrument) Hamana Factory in Hamakita was ready to begin production of the YA-1, and the first bikes were delivered to dealers in February. This new motorcycle had been heavily influenced by

3000-415: The coal fire as readily as stamping license plates, and Matter-Subtracting might mean casually whittling a pencil point as readily as it might mean precision grinding the final form of a laser deposited turbine blade. A precise description of what a machine tool is and does in an instant moment is given by a 12 component vector relating the linear and rotational degrees of freedom of the single work piece and

3075-427: The concepts of accuracy and precision , efficiency , and productivity become important in understanding why the machine-constrained option adds value . Matter-Additive, Matter-Preserving, and Matter-Subtractive "Manufacturing" can proceed in sixteen ways: Firstly, the work may be held either in a hand, or a clamp; secondly, the tool may be held either in a hand, or a clamp; thirdly, the energy can come from either

Yamaha YA-1 - Misplaced Pages Continue

3150-485: The contemporary DKW model RT125 , and like the DKW was driven by a 125 cc two-stroke , single cylinder engine , but the YA-1 designers paid particular attention to materials, assembly, and engineering upgrades, such as going from a three-speed to a four-speed transmission. With confidence in the new direction that Genichi Kawakami was taking, Nippon Gakki founded Yamaha Motor Co., Ltd. on July 1, 1955, and made Kawakami

3225-447: The cutting or shaping. All machine tools have some means of constraining the workpiece and provide a guided movement of the parts of the machine. Thus, the relative movement between the workpiece and the cutting tool (which is called the toolpath ) is controlled or constrained by the machine to at least some extent, rather than being entirely "offhand" or " freehand ". It is a power-driven metal cutting machine which assists in managing

3300-424: The definition, the term, arising at a time when all tools up till then had been hand tools , simply provided a label for "tools that were machines instead of hand tools". Early lathes , those prior to the late medieval period, and modern woodworking lathes and potter's wheels may or may not fall under this definition, depending on how one views the headstock spindle itself; but the earliest historical records of

3375-459: The drawings, paintings, and sculptures of artists such as Michelangelo or Leonardo da Vinci , and of countless other talented people, show that human freehand toolpath has great potential. The value that machine tools added to these human talents is in the areas of rigidity (constraining the toolpath despite thousands of newtons ( pounds ) of force fighting against the constraint), accuracy and precision , efficiency , and productivity . With

3450-403: The economical production of interchangeable parts . Many historians of technology consider that true machine tools were born when the toolpath first became guided by the machine itself in some way, at least to some extent, so that direct, freehand human guidance of the toolpath (with hands, feet, or mouth) was no longer the only guidance used in the cutting or forming process. In this view of

3525-585: The hand(s) holding the tool and/or the work, or from some external source, including for examples a foot treadle by the same worker, or a motor, without limitation; and finally, the control can come from either the hand(s) holding the tool and/or the work, or from some other source, including computer numerical control. With two choices for each of four parameters, the types are enumerated to sixteen types of Manufacturing, where Matter-Additive might mean painting on canvas as readily as it might mean 3D printing under computer control, Matter-Preserving might mean forging at

3600-497: The industry. Belt-driven bicycle A belt-driven bicycle is a chainless bicycle that uses a flexible belt , typically a synchronous toothed design, in order to transmit power from the pedals to the wheel. The application of belt drives to bicycles is growing, especially in the commuter bicycle market, due to the low maintenance and lubrication-free benefits. Belt drives are also available for stationary and fitness bicycles. Tensioning can be implemented in all

3675-537: The master plane gages were produced dates back to antiquity but was refined to an unprecedented degree in the Maudslay shop. The process begins with three square plates each given an identification (ex., 1,2 and 3). The first step is to rub plates 1 and 2 together with a marking medium (called bluing today) revealing the high spots which would be removed by hand scraping with a steel scraper, until no irregularities were visible. This would not produce true plane surfaces but

3750-415: The metal into shape without cutting off swarf, such as rolling, stamping with dies , shearing, swaging , riveting , and others. Thus presses are usually included in the economic definition of machine tools. For example, this is the breadth of definition used by Max Holland in his history of Burgmaster and Houdaille , which is also a history of the machine tool industry in general from the 1940s through

3825-454: The motorcycle had become a widespread means of transportation in Japan after World War II due to ease of production and economy of purchase and use. Japanese motorcycle production increased from 10,000 units in 1950 to 750,000 in 1954, with over 100 domestic manufacturers. Due to the strong expansion of the market, Yamaha Motor Co. decided to convert to the production of motorcycles, and found in

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3900-439: The need for a frame with a split already in it. Veer has also shown a concept where the rear cog can change size (and thus gearing ), a concept that is reminiscent of derailleurs and implies that a hub gear with planetary gears may not be necessary in order to implement multi-speed gears on a belt-driven bike. The possibilities for belt-driven bicycles are increasing as manufacturers of internal hub gears (gears inside

3975-633: The needed relative motion between cutting tool and the job that changes the size and shape of the job material. The precise definition of the term machine tool varies among users, as discussed below . While all machine tools are "machines that help people to make things", not all factory machines are machine tools. Today machine tools are typically powered other than by the human muscle (e.g., electrically, hydraulically, or via line shaft ), used to make manufactured parts (components) in various ways that include cutting or certain other kinds of deformation. With their inherent precision, machine tools enabled

4050-522: The new company's first president. Staffed by 275 employees, the new motorcycle manufacturer built about 200 units per month by the end of 1955. That same year, Yamaha entered its new YA-1 in the two biggest race events in Japan. They were the 3rd Mt. Fuji Ascent Race held in July 1955, and the 1st Asama Highlands Race in November. In these debut races, Yamaha won the 125 cc class. The following year,

4125-445: The newly developed additive manufacturing processes, which are not about cutting away material but rather about adding it, are done by machines that are likely to end up labeled, in some cases, as machine tools. In fact, machine tool builders are already developing machines that include both subtractive and additive manufacturing in one work envelope, and retrofits of existing machines are underway. The natural language use of

4200-406: The operator would unlock the y-axis on the cross slide of the lathe, assuming that our examples were equipped with that, and then the operator would apply some method of traversing the facing tool across the face of the cylinder being cut and a depth combined with the rotational speed selected which engages cutting ability within the power of range of the motor powering the lathe. So the answer to what

4275-445: The path of expanding their entrepreneurship from manufactured end products and millwright work into the realm of building machine tools for sale. Important early machine tools included the slide rest lathe, screw-cutting lathe , turret lathe , milling machine , pattern tracing lathe, shaper , and metal planer , which were all in use before 1840. With these machine tools the decades-old objective of producing interchangeable parts

4350-410: The primary driven gear is turned by means of a kick idling gear and kick pinion . This enables the rider to simply pull the clutch lever on the handlebar (i.e., disengage the clutch) and then to kick-start engine, regardless of whether the transmission is in neutral or in (any) gear. This mechanism is now the established kick start system for motorcycles worldwide. The 2011 Tokyo Motor Show included

4425-541: The rear hub, which allow riders of belt-driven bicycles to shift easily) introduce new designs such as the Shimano Alfine 11 and Fallbrook Technologies's NuVinci . Other major internally geared hub makers include SRAM , Sturmey-Archer , Rohloff and Kindernay . Another option to provide gears is to create a gearbox bicycle using a bracket-mounted gearbox like the Pinion P.18. The belts are typically made by

4500-414: The root causes already listed. For example, rolling-element bearings are an industry of themselves, but this industry's main drivers of development were the vehicles already listed—trains, bicycles, automobiles, and aircraft; and other industries, such as tractors, farm implements, and tanks, borrowed heavily from those same parent industries. Machine tools filled a need created by textile machinery during

4575-399: The same ways that single-speed chain drives can be tensioned. The fork ends for the rear axle are horizontal, in line with the belt, with or without chain tugs, which allows the distance between the rear wheel axle and the crank axle to be adjusted. The fork ends themselves can be moved, to change the distance between the rear wheel axle and the crank spindle. The fork ends are fixed but there

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4650-408: The single tool contacting that work piece in any machine arbitrarily and in order to visualize this vector it makes sense to arrange it in four rows of three columns with labels x y and z on the columns and labels spin and move on the rows, with those two labels repeated one more time to make a total of four rows so that the first row might be labeled spin work, the second row might be labeled move work,

4725-413: The skill into the tool", in contrast to the toolpath-constraining skill being in the person who wields the tool. As an example, it is physically possible to make interchangeable screws, bolts, and nuts entirely with freehand toolpaths. But it is economically practical to make them only with machine tools. In the 1930s, the U.S. National Bureau of Economic Research (NBER) referenced the definition of

4800-437: The surfaces comprising the features of machine parts by removing chips. These chips may be very rough or even as fine as dust. Every machine tools supports its removal process with a stiff, redundant and so vibration resisting structure because each chip is removed in a semi a synchronous way, creating multiple opportunities for vibration to interfere with precision. Humans are generally quite talented in their freehand movements;

4875-404: The terms varies, with subtle connotative boundaries. Many speakers resist using the term "machine tool" to refer to woodworking machinery (joiners, table saws, routing stations, and so on), but it is difficult to maintain any true logical dividing line, and therefore many speakers accept a broad definition. It is common to hear machinists refer to their machine tools simply as "machines". Usually

4950-413: The third row might be labeled spin tool, and the fourth row might be labeled move tool although the position of the labels is arbitrary which is to say there is no agreement in the literature of mechanical engineering on what order these labels should be but there are 12 degrees of freedom in a machine tool. That said it is important to remember that this is in an instant moment and that instant moment may be

5025-438: The way parts are made. Examples of machine tools are: When fabricating or shaping parts, several techniques are used to remove unwanted metal. Among these are: Other techniques are used to add desired material. Devices that fabricate components by selective addition of material are called rapid prototyping machines. The worldwide market for machine tools was approximately $ 81 billion in production in 2014 according to

5100-579: Was Whitworth who contributed the refinement of replacing the grinding with hand scraping. Sometime after 1825, Whitworth went to work for Maudslay and it was there that Whitworth perfected the hand scraping of master surface plane gages. In his paper presented to the British Association for the Advancement of Science at Glasgow in 1840, Whitworth pointed out the inherent inaccuracy of grinding due to no control and thus unequal distribution of

5175-468: Was apparently successful, but was offered mainly in Japan. Bridgestone offered belt-drive bicycles in the USA until they left the market about 1994. Since their innovation, they have continuously offered belt-drive bicycles in Japan including their best-selling Albelt model. In 1984 and 1985, Mark Sanders , a designer who had earned his degree in mechanical engineering from Imperial College , London, designed

5250-428: Was delayed many decades, in part because the programmable control methods of musical boxes and looms lacked the rigidity for machine tool toolpaths. Later, electromechanical solutions (such as servos ) and soon electronic solutions (including computers ) were added, leading to numerical control and computer numerical control . When considering the difference between freehand toolpaths and machine-constrained toolpaths,

5325-429: Was finally realized. An important early example of something now taken for granted was the standardization of screw fasteners such as nuts and bolts. Before about the beginning of the 19th century, these were used in pairs, and even screws of the same machine were generally not interchangeable. Methods were developed to cut screw thread to a greater precision than that of the feed screw in the lathe being used. This led to

5400-430: Was introduced in the early 1980s. It used a tooth-belt drive like auto timing belts and Harley-Davidson drive belts, along with a novel two-part chainring that increased belt tension with increasing load. The Picnica was a folding bicycle , and part of the appeal of the belt drive was cleanliness. The Picnica was a small-wheel bicycle , so belt tension may have been less than on a bicycle with standard-size wheels. It

5475-529: Was not until the later Middle Ages and the Age of Enlightenment that the modern concept of a machine tool—a class of machines used as tools in the making of metal parts, and incorporating machine-guided toolpath—began to evolve. Clockmakers of the Middle Ages and renaissance men such as Leonardo da Vinci helped expand humans' technological milieu toward the preconditions for industrial machine tools. During

5550-469: Was utilized on some Trek bicycles and the Sladda utility cycle marketed by IKEA of Sweden. After reports of failures of the belt itself and a recall, CDS was withdrawn from the belt-drive bicycle market. In 2018, Veer Cycles created the first belt drive conversion kit that allows riders to convert their chain driven bikes to belt drives. The belt is spliced to fit through the rear triangle and eliminates

5625-427: Was worked with a file and chisel and could be made into gears and other complex parts; however, hand working lacked precision and was a slow and expensive process. James Watt was unable to have an accurately bored cylinder for his first steam engine, trying for several years until John Wilkinson invented a suitable boring machine in 1774, boring Boulton & Watt's first commercial engine in 1776. The advance in

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