USA 08The Lineage of American Grinding Machines

Sandstone and emery: the beginnings of the grinding machine (1818–1859)

In the early 19th century, grinding meant sharpening blades or polishing surfaces; it was not a process for setting dimensions. Wheels were made of natural sandstone, like stones from a riverbed, or of grains of emery, a natural alumina rich in iron. In 1818 Thomas Blanchard agreed to build a machine for grinding gun barrels for the Springfield armory. A large sandstone wheel, thicker than the barrel was long, was driven by a belt at 400 rpm, while a worker turned the barrel with a handle and pressed it against the wheel by leaning his body on a lever^[1]. Large natural stones were heavy and poorly balanced, so accuracy depended on the worker's skill.

Even so, American machinists turned early to the idea of "bringing parts to size by grinding." The machine in the patent that James Wheaton of Providence (Rhode Island) obtained in May 1834 held the work on centers on a carriage and moved it automatically back and forth in front of a power-driven wheel. The centers contained springs that let the work expand from the heat of grinding, the wheel head could be advanced by a screw as the wheel wore, and a former plate let it grind shapes as well. The account of Jonathan Bridges, a contemporary of Wheaton, shows that such "spindle grinders" were in use before 1830. The historian Woodbury considers that the basic elements of today's cylindrical grinder were almost all present by this point^[1].

Machines for grinding flat surfaces appeared too. J. W. Stone's 1831 patent for a surface grinder had a power-fed flat table and a spring-loaded wheel (the specification was lost in the Patent Office fire). The surface grinder that Samuel Darling patented in 1853 had a table that traveled automatically back and forth on V-ways under a horizontal-spindle wheel, with cross feed and vertical adjustment, a form much like today's surface grinder^[2][1]. Darling joined Brown & Sharpe in 1866, and the patent passed to the company.

What changed in this era. With the move from wooden frames to iron frames, and from hand cranking to powered rotation and powered feed, the grinder became a "machine." But wheels were natural stone, or handmade cast-iron disks coated with glue and sprinkled with emery grains, and their properties were inconsistent. Accuracy still came from the lathe, and grinding remained a final polish.

Brown & Sharpe's universal grinder (1860–1885)

What turned grinding into precision machining were watches and sewing machines. Around 1860 a small precision grinder was built for a watch company in Nashua (New Hampshire); in 1862 it moved to the American Watch Company in Waltham and became a tool for making watch parts to interchangeable accuracy^[1].

A grinding lathe for sewing machines

J. R. Brown & Sharpe of Providence had been building Willcox & Gibbs sewing machines since 1858. Needle bars and shafts were hardened, so they could not be finished on a lathe. The company therefore mounted an emery wheel on the carriage of a 14-inch lathe, added automatic feed and reversing, and built a grinding lathe (drawing of November 1864). A driver to turn the work on stationary (dead) centers, a steady rest and a water nozzle were added in turn; about 30 were built over several years, and it appeared in the company's first catalog in 1867^[1][3]. But as a converted lathe it lacked rigidity, so much so that weights were placed on the carriage to damp vibration. The first operator, Thomas Goodrum, was paid 7 dollars a day; grinding was a well-paid master's craft^[1].

A machine designed for grinding from the start

Joseph R. Brown conceived a machine designed from scratch for grinding rather than a converted lathe. A drawing dated April 10, 1868, put a swivel table, adjustable in angle, on top of the reciprocating table, and the design also had a swiveling headstock. The shop was busy and the project was shelved, but construction began in June 1874; with a swiveling wheel head, a cross-feed handwheel and an internal grinding attachment added, it appeared in the catalog of January 1, 1875^[1][4].

In 1876 Brown & Sharpe showed this universal grinder at the Centennial Exposition in Philadelphia, where the judges praised it as a sturdy, well-thought-out machine. The first machine shown was sold after the exhibition to a firm in Mulhouse, and the first machine to be used in the company's own shop started running a few days after Brown died on July 23^[4][3]. Woodbury's book says "the 1876 Paris Exposition," but there was no world's fair in Paris in 1876, so we follow the accounts of Burlingame, an engineer at the company (1910), and Roe (1916). The patent (US Patent 187,770) was granted to his executors on February 27, 1877, and covered the basics of today's universal grinder, such as the swiveling headstock on a swivel table, and even a device for form grinding^[5][6].

Henry M. Leland, then a foreman at Brown & Sharpe and later the founder of Cadillac, recalled that what this machine brought to the shop was that parts could be hardened first and then ground to exact size, that the ways were protected from the abrasive, and that running the work on dead centers kept spindle errors out of the work^[1]. Today's sequence of removing hardening distortion by grinding began here.

Surface and internal grinders, and grinding heavy rolls

Brown & Sharpe followed with a planer-type surface grinder and a plain cylindrical grinder in 1877, an internal grinding attachment in 1880, and column-type (1883), knee-type (1885) and face-type (1887) surface grinders, so that within ten years the main forms of the grinder were in place. In 1885 it published a handbook for workers, Treatise on Grinding Machines, which explained that grinding could be used on both hardened and soft material, was cheap and fast, and gave good accuracy and finish, and which gave much space to measuring with gauges^[1].

Heavy workpieces called for a different idea. Around 1870 J. Morton Poole built a machine for grinding large paper-mill rolls in which two wheels hung like pendulums and, by gravity, cut only where the roll was thicker than the target. Instead of relying on the straightness of the ways, it used a mechanism that let the workpiece itself correct the error, producing rolls that were straight and uniform in diameter^[1].

A revolution in wheels: vitrified bonds and artificial abrasives (1856–1925)

However precise grinders became, as long as wheels varied in their properties, no body of knowledge could build up about which wheel to run at how many m/s. Until about 1860, machinists made their own wheels by dripping glue on a cast-iron disk, sprinkling it with emery grains and dressing it with an oilstone. They did not last and were good only for light finishing^[1].

Holding the grains together with a "bond"

So solid wheels with the grains held in a bond were tried. In 1859 T. J. Mayall patented a wheel of emery held in vulcanized rubber, sold under the name "Vulcanite" (rubber bonds survive in the regulating wheels of later centerless grinders). Wheels bonded with sodium silicate and fired wheels were also tried^[1].

The vitrified wheel (fired with clay and feldspar), the mainstream wheel today, was born in a pottery in Worcester (Massachusetts). In 1873 Swen Pulson, a potter at F. B. Norton's works, succeeded on his third attempt in making a wheel by firing emery with clay. In February 1877 Norton patented a version using feldspar, and in June 1885 the Norton Emery Wheel Company (later the Norton Company) was formed to take over the business^[1][7][3]. The hardness (grade) of a wheel was judged by John Jeppson from the feel of pushing a tool into it, and he ranked the grades alphabetically from soft to hard. This led to today's practice of expressing wheel hardness with letters^[1]. In 1884 tests by Gilbert Hart in Detroit showed that corundum, a natural, almost pure alumina, cut far better than emery, and by 1893 corundum had become the main abrasive^[1].

Wheels had to be considered together with machines. Charles H. Norton (no relation to F. B. Norton), who came to Brown & Sharpe in 1886, found that the cause of the company's grinding troubles was poorly balanced wheels and peripheral speeds too high for the wheel grade. Looking at grinding swarf under a microscope, he also showed that a correctly chosen wheel produces small chips, just like a cutting tool^[1]. The Norton Company tested wheels at twice their working speed and printed the results on the wheel label before shipping^[1].

Carborundum and artificial alumina

Natural corundum was expensive and variable. In March 1891 Edward G. Acheson, who worked for an electric lighting company, found hard, blue, glittering crystals around a carbon electrode in an experiment heating clay and carbon in an electric furnace. It was silicon carbide (SiC), and from carbon and corundum he named it "Carborundum." It was the first artificial abrasive, one not found in nature^[11][1]. Acheson founded The Carborundum Company on September 21, 1891, patented the process in 1893, and in 1895 moved to Niagara Falls (New York) in search of cheap hydroelectric power^[12][13][1]. Carborundum wheels went on sale in 1896; very hard but brittle, they suited hard, brittle materials such as cast iron and nonferrous metals. As was found later, on steel alumina, which is softer than silicon carbide, lasts longer^[1].

The artificial abrasive for steel was the fused alumina devised by Charles B. Jacobs in 1897: bauxite mixed with a little coke and iron scrap is melted in an electric furnace, and the impurities sink out as metal. The Norton Emery Wheel Co. acquired rights to the process, opened a plant at Niagara Falls in 1901 and named the product Alundum. The furnace devised by Aldus Higgins in 1904, cooled with water on the outside so that the molten charge itself formed the furnace lining, halved production costs; by 1906 emery and corundum had disappeared from Norton wheels, and the company's name changed to Norton Company. In 1910 wheels of high-purity white alumina appeared^[1][14]. Trade journal statistics show that US production of artificial abrasives in 1906 was mainly Carborundum and Alundum^[11].

What it means on the shop floor. Today's standard wheel markings, "A (alumina), WA (white alumina), C/GC (silicon carbide)," "grain size," "grade A–Z," "structure" and "V (vitrified), B (resinoid), R (rubber)," are based on the abrasives and bonds that appeared here and on Jeppson's way of ranking hardness. The rule of alumina for steel and silicon carbide for cast iron, nonferrous metals and cemented carbide also came out of the experience of this era. For details, see Grinding Basics: Grinding wheels.

Heavy grinding and the automobile: Norton and Landis (1886–1919)

Until the 1890s, grinding was a "finish after the finish," a light polish after the lathe had brought the part close to size. It was Charles H. Norton who turned it into heavy grinding (production grinding), in which work rough-turned on the lathe is ground directly to size.

Norton's idea: heavy machines, wide wheels, plunge grinding

At Brown & Sharpe, Norton redesigned the universal grinder, and in 1897 he also patented an automatic infeed. At an internal meeting late that year he put forward the following ideas. If the machine is made heavy and stiff enough, the machine itself can be used as a micrometer (turn the dial by 0.00025 inch, and the work becomes 0.00025 inch smaller). Use a wide wheel, as much as a foot across the face, and grind by plunging the wheel in without traversing the work along its length (plunge grinding). Stop fine finish-turning on the lathe and grind with plenty of power: power is cheaper than labor. But the meeting rejected the ideas, saying the wheels would wear quickly and the work would chatter and burn^[1].

In 1900 Norton moved to Worcester and became chief engineer of the Norton Grinding Company, set up by investors in the Norton Emery Wheel Co.^[3][9]. He began designing an 18 × 96-inch cylindrical grinder in March 1900, and two machines were completed in November. A heavy, internally braced bed sat on three-point supports; a wheel 24 inches in diameter and 2 inches wide was driven with plenty of power; infeed was precise and automatic; and 50 gallons a minute of grinding fluid kept the work from expanding with heat. The wheel was four times the size of earlier ones, cut 16 times faster, and ground 1 cubic inch of steel a minute to an accuracy of 0.001 inch^[1][16]. The first machine worked for about 30 years at a printing-press maker and is now at The Henry Ford in Dearborn^[16].

Landis: grinders with a traversing wheel head, and crankshafts

Around the same time another grinder maker was growing up in Waynesboro (Pennsylvania). A. B. Landis, who worked at the farm-machinery company Geiser, could not get the company to buy a Brown & Sharpe machine for the toolroom, so in 1886 he built a cylindrical grinder himself. Instead of moving the work table, his design moved the wheel head lengthwise, which suited long, heavy work; this feature was carried over into every later Landis machine^[6]. With his elder brother F. F. Landis he started Landis Bros. in 1889, which later became Landis Tool Co.^[8][10]. According to a trade journal advertisement of May 1897, a new plant was built on the site of the Landis Bros. works, which had burned down, and the business was reorganized as Landis Tool Co. with capital of $100,000^[15]. A trade journal of 1906 wrote that anyone buying a wet cylindrical grinder had only three makers to choose from: Norton Grinding, Landis Tool and Brown & Sharpe^[6]. The same article noted that wheel widths had grown from 3/4 inch to 1–3 inches, steady rests had multiplied to one for every 12 inches of length, and grinding fluid had grown from a thin stream to a full 1-inch pipe, so that the grinder had changed from a delicate toolroom machine into one that competed with the lathe in the amount of metal it removed^[6].

The automobile became the grinder's biggest customer. A crankshaft is a part from which much metal must be removed at both the pins and the main journals, with strict requirements for size and surface roughness. Norton plunge-ground the width and corner radius of a pin at once with a single wheel, cutting a job that had taken 5 hours of turning, filing and polishing to 15 minutes. Grinder operators were paid 85 cents an hour against 30 cents for lathe hands, so at first the crankshafts of most American cars were sent to Norton's plant for grinding. In 1905 Locomobile became the first to buy grinders for its own use, and later Ford ordered 35^[1]. Also in 1905, Landis brought out a crankshaft grinder that supported the crankshaft at both ends with two rotating headstocks to prevent twisting, with counterweights and steady rests^[1][6][10]. In 1912 A. B. Landis patented a camshaft grinder. A large master cam turning on the same axis as the work made the wheel head follow its profile, and the cams on one shaft were ground in turn, ending the practice of grinding cams separately and fitting them to the shaft^[24][1].

Heald: cylinder grinders that orbit the wheel spindle

Worcester's other grinder maker was James N. Heald's Heald Machine Co. Heald moved the family business to Worcester in 1903 and in 1904 brought out a rotary grinder that ground both faces of piston rings^[17][1]. Automobile cylinders were thin-walled: in boring, the tool deflected at hard spots and dug in at soft ones, so the bores did not come out round. Heavy cylinder blocks could not be rotated, so Heald kept the work still and in 1905 developed a cylinder grinder that moved the wheel spindle eccentrically in a circle (planetary motion). The size of the circle was set by the angle between two eccentric sleeves, and moving the table sideways brought the next cylinder into position. It eliminated boring, reaming and lapping, and became the standard machine for automobile engines and for the aircraft engines of World War I^[1][18][19].

At Ford's plant in 1918, 33 special grinders built by Norton ground transmission shafts to a tolerance of 0.0005 inch in a single plunge of a wheel 20 inches in diameter and 6 inches wide, finishing 550 shafts in 8 hours^[1]. In 1919 the wheel maker Norton Company and the grinder maker Norton Grinding Company were united, and Norton remained chief engineer of the machine division into his 80s^[9].

What it means on the shop floor. "Rough on the lathe, finish by grinding," "plunge with a wide wheel," and "get accuracy from machine rigidity and set size with the feed dial" are exactly the ideas Norton put forward around 1900. Automobile engine parts, namely crankshafts, camshafts, cylinders and piston rings, drove the specialization of grinders. This story is also covered in Chapter 3, "Mass Production and the Two World Wars".

⚒Special machines for mass production and precision: centerless, internal, surface and jig (1887–1945)

Bicycles and bearings

Ball bearings cannot work without hardened balls that are truly spherical and uniform in size, and races that are round and concentric. Henry Richardson's 1887 patent for grinding steel balls and the bicycle bearing-cup grinder that Pratt & Whitney brought out in 1899 (with a small wheel turning at 28,500 rpm) are examples of how grinders made bearings possible, and bearings in turn reduced friction and wear in machines^[1]. In 1909 William L. Bryant, formerly chief draftsman at Jones & Lamson, founded the Bryant Chucking Grinder Co. in Springfield (Vermont). Its grinder held the work in a chuck and moved three wheels, a small, fast wheel for the bore, one for the outside diameter and one for the face, automatically with cams and stops; it supported mass production of the inner and outer rings of automobile bearings^[20][1].

Automatic sizing and hydraulics

In mass production, the time spent measuring is the biggest waste. Pratt & Whitney's 1908 cylindrical grinder switched automatically to a fine feed near final size and stopped at a set size even as the wheel wore^[1]. Feeds became hydraulic from the early 1900s, making machines easier to automate. In internal grinding, Heald began developing automatic sizing in 1922 and brought out the Size-Matic, which switched from roughing to finishing at size and stopped while grinding the bore. The name appears in a 1926 trade journal index and in advertisements, which claimed that at Delco Light, a maker of refrigerators, output tripled and rejects fell below 1%^[29][30][1]. Landis also brought out its first automatic camshaft grinder and automatic internal grinder in 1928. Grinding of automobile valve tappets progressed from center-type machines in 1920 to fully automatic hopper-fed centerless grinding in 1929, with one worker tending three machines and grinding 1,350 pieces an hour^[1].

Centerless grinding: grinding without support

In centerless grinding, the work is held neither on centers nor in a chuck. It is placed between the grinding wheel and a slowly counter-rotating regulating wheel, and supported from below by a blade. The grinding wheel tries to drag the work around, but the rubber-bonded regulating wheel acts as a brake, and the difference in speed does the cutting. If the center of the work is placed slightly above the line joining the centers of the two wheels, the work becomes rounder as it is ground, even if it started slightly out of round. Tilting the regulating wheel slightly makes the work advance axially by itself, so parts can be passed through one after another (through-feed)^[1].

The decisive invention was a patent filed in March 1915 and granted in January 1917 to Lewis R. Heim of the Ball and Roller Bearing Co. of Danbury (Connecticut), which made bearing rollers. Using a power-driven regulating wheel instead of a stationary pressure plate, and a blade to set the direction of the forces, it tightened roller tolerances from 0.0005 inch to 0.00025 inch^[25][26]. Cincinnati Milling Machine Co. acquired the patent and in 1922 built a centerless grinder for mass production. The grinding wheel was 20 inches in diameter and the regulating wheel 12 inches, both with diamond dressing devices, and it could also infeed-grind shouldered push rods and valve tappets^[1][28][26]. By 1925 it was grinding 350 valve stems 6 inches long an hour, and the idea that the wheel is an expendable consumable spread through factories. In 1932 large machines for grinding cast-iron crankshafts and pistons also appeared^[1]. In 1933 Heald, with the cooperation of Cincinnati Grinders and GM's Hyatt bearing division, brought out the internal centerless grinder, which supports the outside diameter at three points and grinds the bore. The inside and outside diameters are perfectly concentric, which suited mass production of bearing rings^[1][32].

Surface grinding: the magnetic chuck and Blanchard

After taking shape in the 1880s, the surface grinder remained a toolroom machine. What changed it was the magnetic chuck, devised by O. S. Walker of Worcester in 1896. Thin parts could be held without distortion, and there was no longer any need to make fixtures as on planers and milling machines^[1]. Heald brought out a rotary-table grinder in 1904, and from 1909 the Blanchard Machine Co. of Cambridge (Massachusetts) began building surface grinders with a rotary table turning under a cylindrical wheel on a vertical spindle. This method of grinding the faces of thick castings and forgings flat quickly is still sometimes called "Blanchard grinding"^[21][22]. A 1915 American grinding handbook described Blanchard's motor-driven vertical-spindle surface grinder (with an eight-speed rotary table) as a standard machine^[23]. Regional makers specializing in surface and tool grinders also grew up, such as Gallmeyer & Livingston of Grand Rapids (Michigan)^[67]. Woodbury writes that surface grinders finished machine ways and tables quickly and cheaply, replacing part of the costly work of hand scraping (though scraping, which leaves oil pockets, remained for the final finish)^[1].

The jig grinder and thread grinding

In die and gauge holes, positional accuracy is everything. The Moore Special Tool Co. of Bridgeport (Connecticut) built a jig borer with a hardened, ground and lapped lead screw in the early 1930s, and in 1940 a jig grinder. Until then the only way was to bore holes while the steel was soft, allowing for hardening distortion; now holes could be ground to the correct position after hardening, raising the accuracy of progressive dies, watch dies and gauges^[35][36][37].

Threads had long been mass-produced on automatic screw machines, and only taps and gauges were ground. Aircraft demand in World War II made thread grinding a mass-production process, with accuracy of 0.0002 inch on pitch diameter and 5 minutes on flank angle. For forming the wheel before grinding, crush dressing, in which a steel roll is pressed against the wheel to transfer its form, came into wide use, allowing wheels to be re-formed faster than by shaping each one with a diamond^[1]. On the machine side, a trade journal introduced the thread grinder that Ex-Cell-O of Detroit showed at the 1935 Cleveland machine tool show as “the first commercial thread grinder of American make to be offered for sale”^[33][34]. Gear grinding also spread, to make hardened automobile gears quieter, but that is covered in the chapter on American gear machines.

★Superabrasives, NC and industry consolidation (1930–)

Diamond wheels

When cemented carbide tools spread in the late 1920s, how to grind them became a problem. In October 1930 Norton's Baalis Sanford made a trial small diamond wheel bonded with resin, and in 1934 Norton put a 7-inch diamond wheel on sale. The diamonds were placed only in a layer 1/32–1/8 inch thick on the periphery^[1]. A 1936 trade journal wrote that although the abrasive cost $2,500 a pound, it paid for itself because carbide-tipped milling cutters could be ground without having to match each tooth again^[31]. In 1939 metal-bonded diamond wheels also appeared, making it possible to grind glass and ceramics. In 1946 Norton's Raymond Ridgeway put into practice a method of growing alumina crystals of a set size in the furnace and using them as abrasive without crushing^[1].

Synthetic diamond and CBN (Borazon)

What ended the dependence on natural diamond was the research laboratory of General Electric (GE). In February 1955 GE announced that it had made diamond artificially at high pressure and temperature, and the researchers' paper appeared in Nature in July^[38][39]. GE put man-made diamond on the market as an industrial abrasive in 1957, and by 1960 it held about a tenth of the US market^[44][45]. In 1957 Robert H. Wentorf of the same team announced that he had converted boron nitride under ultra-high pressure into a cubic crystal form (the same structure as diamond). GE named it "Borazon." Trade journals of the time reported that it was hard enough to scratch diamond and kept its hardness at temperatures at which diamond burns^[46][40].

Diamond is carbon, so at high temperatures it reacts with iron and wears away. CBN, which reacts little with iron, was expected to become the superabrasive for grinding hardened steel, but it took 12 years to become a product: GE put Borazon on sale for precision grinding of hardened ferrous metals in 1969^[54]. CBN wheels wear little and hold their form, so they can be run fast to grind mass-produced parts such as camshafts without drifting from size. How Japanese grinder makers grew strongly in this direction from the 1970s can be seen in the Japanese Archive, Chapter 3 "CBN and high-speed grinding" event.

NC grinders

Numerical control of grinders began with machines that grind contours. In 1967 Moore built the No. 3 jig grinder, which ground contours under numerical control, and by 1970 an NC-equipped Moore No. 3 was listed in the index of a British trade journal^[37][50]. As for when CNC began on cylindrical and surface grinders in the US, we could not confirm the year from primary sources in this research (a Japanese maker exhibited an NC cylindrical grinder in 1964; see Japanese Archive, Chapter 3, "NC grinders"). The birth of NC itself is covered in Chapter 4, "The Birth of NC and the Machining Center".

Corporate consolidation

In the second half of the 20th century the old grinder makers became parts of larger companies. Heald was bought by Cincinnati Milling Machine Co. in September 1955 and became its subsidiary, and in 1980 it was the Heald Division of Cincinnati Milacron^[41][42][19]. Bryant became a subsidiary of Ex-Cell-O in 1958, Landis Tool became a division of the conglomerate Litton Industries in 1967, and Norton, fending off a hostile takeover by Britain's BTR in 1990, became part of France's Saint-Gobain^{[47][51][53][56]}. In October 1998 Cincinnati Milacron sold its machine tool business to UNOVA, which also owned Landis Grinding Systems^[58][59]. In December 2005 UNOVA sold Landis (including Landis in the US and Landis Lund in the UK) to France's Fives-Lille group, and the old crankshaft and camshaft grinder maker became part of a French company^[60][61]. Moore joined PMT Group in 1994 and in 1997 set up Moore Nanotechnology Systems, a maker of ultra-precision machines^[37]. Blanchard surface grinders have been carried on since 2004 by Bourn & Koch of Rockford (Illinois)^[22].

What it means on the shop floor. Today's division of labor, with diamond wheels for carbide tools, CBN wheels for mass-produced hardened steel, jig grinders for dies that need accurate hole positions and centerless grinders for mass production of bearings and small parts, took shape through the inventions of the 1930s–60s described here. When looking at used machines, knowing how maker names changed (Heald → Cincinnati, Landis → Fives, Blanchard → Bourn & Koch) tells you where to ask about parts and service.

Links with Japan

Japanese grinders began by following American machines. According to the product history of Okuma Iron Works (now Okuma), in 1918 the company built the Type GA-1 tool grinder from army arsenal drawings, modeled on the American "Norton" No. 1 universal tool grinder; in 1919 it built internal grinders modeled on products of the American firm Heald; and in the late Taisho era it built the Type GA-2 universal tool grinder, modeled on Brown & Sharpe's No. 13^[69]. Okuma's Type GHU hydraulic universal grinder, 500 of which were built in wartime and which laid the foundation for postwar grinder production, was also modeled on an American Landis grinder^[70][71] (Japanese Archive, Chapter 3 timeline).

After the war, Japanese grinder makers gained strength through mass production of bearings and auto parts, but a 1983 report by the US International Trade Commission (USITC) stated that US machine tools exported to Japan were mainly high-precision gear-cutting, grinding and milling machines, and that Japanese makers had not yet caught up with that technology^[55]. On the other hand, Japanese grinder makers were among the early users of CBN for mass-production grinding of hardened steel: Toyoda Machine Works began CBN research around 1972, and in 1977 received an award from the Japan Society for the Promotion of Machine Industry for a CBN production cam grinder^[72] (Japanese Archive, Chapter 3).

FAQ

Who built the first universal grinder?

The form of today's universal grinder was set by Joseph R. Brown of Brown & Sharpe. He had concept drawings made in 1868, began building the machine in 1874 and exhibited it at the 1876 Centennial Exposition in Philadelphia. The patent was granted to his estate on February 27, 1877. Similar machines were built around the same time in watch factories and by Furbush of Lynn (Massachusetts), but it was the Brown & Sharpe machine that came into wide use and served as the model.

Are Norton Company and Norton Grinding Company the same company?

They were originally separate companies. Norton Company (at first the Norton Emery Wheel Company, 1885) was a wheel maker that grew out of F. B. Norton's pottery, and Norton Grinding Company (1900) was the grinder maker where Charles H. Norton became chief engineer. The two men were not related. The two companies were united in 1919.

Who invented centerless grinding?

The idea of grinding work without supporting it goes back to the 19th century, but the decisive step toward today's method, grinding between a grinding wheel and a counter-rotating regulating wheel with the work resting on a blade, was the patent of Lewis R. Heim, a maker of bearing rollers (filed 1915, granted 1917). Cincinnati Milling Machine Co. acquired the patent, built a machine for mass production in 1922 and spread its use.

When did CBN wheels first appear?

CBN (cubic boron nitride) was synthesized by GE's Robert H. Wentorf, who announced it in 1957, and GE named it "Borazon." GE put it on sale as an industrial abrasive for grinding hardened steel in 1969. In Japan it came into use for mass-production grinding of camshafts and other parts from the 1970s, driving faster grinders and the move to CNC.