USA 06The Lineage of American Lathes

Armory lathes and copying lathes (c. 1798–1850)

Wilkinson's screw-cutting lathe

The record of American metal-cutting lathes begins with David Wilkinson of Pawtucket, Rhode Island. Wilkinson, who made textile machinery and the large screws of oil presses, was dissatisfied with the accuracy of hand-made screws and devised a machine that held a screw between two centers and cut it. The machine of his patent of December 14, 1798 was driven by a water wheel that turned the workpiece and the lead screw together, and a half nut engaging the lead screw fed a heavy tool carriage. It had no change gears, so it could only cut threads of the same pitch as its lead screw. On this basis, by 1806 Wilkinson built a general-purpose lathe whose tool carriage was fed by a screw (a slide lathe), and it came into wide use at the armories and elsewhere^[1][2]. In 1848, Congress awarded $10,000 for his contribution of "the principle of the gauge and slide lathe"^[2]. Roe, however, says it is unclear whether it was as good as Maudslay's lathe in Britain at the same time, and Woodbury judges that "it was not a precise machine, but it served for work on an industrial scale" (for British lathes, see the chapter on British lathes).

Blanchard's copying lathe: "copying" a shape

What the armories wanted was to make shapes that are not straight, such as gun barrels and gunstocks, identically without relying on the hands of skilled workers. Thomas Blanchard first built, at Asa Waters's armory in Millbury, a lathe that moved its cutter by a cam to turn a gun barrel right up to the flats at its breech; it was also in use at the Springfield Armory by 1818. Next came the copying lathe for turning gunstocks, which he patented in 1819^[3][2].

This is how it works. An iron pattern (the master) and a wooden blank turn slowly at the same speed; a guide wheel bears on the pattern and a rotating cutter on the blank. The two are mounted on the same frame, so as the guide wheel follows the bumps and hollows of the pattern, the cutter moves by the same amount and copies the same shape onto the blank. Because the cutting tool is a rotating cutter, the mechanism is closer to a shaper than a lathe, but the name "Blanchard lathe" stuck^[3]. At Springfield, to cope with variations in the dimensions of the metal parts, they even used machines that cut the stock using the actual lockplate as the pattern, and reportedly kept doing so until the metal parts became accurate enough in 1840^[2]. Blanchard's 1822 gunstock lathe still survives at the Springfield Armory historic site^[3].

What changed on the shop floor. The copying lathe replaced "the hand movements of a skilled craftsman" with "a pattern". Making the pattern took effort, but once made, it gave the same shape whoever turned the crank. This idea leads to the hydraulic copying lathe 100 years later, and on to the "program" of the NC lathe. Blanchard's lathe later spread to shoe lasts and ax handles, and much of Blanchard's income came from royalties on this patent^[2].

Turret lathes and automatic screw machines (1845–1916)

Indexing the tools in a row: the birth of the turret

Making a small screw on an engine lathe meant changing the tool, or moving and resetting the tool post, for every drilling, turning, threading and parting-off step. So the idea arose of mounting all the tools from the start and changing to the next tool just by rotating the tool holder. According to an article by E. G. Parkhurst in American Machinist in 1900, Stephen Fitch of Connecticut built, at his own expense in 1845, a machine that cut parts for a government pistol contract in sequence with a horizontal-axis revolving head carrying eight tools, and used it until 1853^[4][2]. At the Sharps rifle works in Hartford, too, J. D. Alvord planned a screw machine with a turret before 1853^[4].

The firm that made it a product was Robbins & Lawrence of Windsor, Vermont. According to Roe, the company built turret lathes as a product in 1854, with drawings by H. D. Stone. The turret had a vertical axis, which later became the standard. The same shop also produced the box tool, which combined steady rests and cutters in one unit, and the hollow mill, and Roe calls the turret "the first radical improvement since Maudslay's slide rest"^[2][5]. The shop building still stands today as the American Precision Museum.

A turret that turns itself: Brown & Sharpe and Pratt & Whitney

In 1861, F. W. Howe of the Providence Tool Co. asked Brown & Sharpe for a turret screw machine to make gun nipples (the small part that takes the percussion cap). J. R. Brown added a device that automatically indexed the turret to the next position as the slide moved back (a ratchet and pawl), and a device that fed and gripped the bar stock while the spindle kept turning. Roe calls this the first machine tool Brown & Sharpe built for sale. In the same year, 1861, Pratt & Whitney of Hartford also began building screw machines of their own design with self-indexing turrets^[2][4]. The operator's job came down to just pushing and pulling a lever.

Automating everything with cams: Spencer's automatic screw machine

The man who replaced even the last "person working the levers" with the machine was Christopher M. Spencer, known for his repeating rifle. The machine of US Patent 143,306 of September 30, 1873 used cams arranged on a single shaft to feed the bar, close the chuck, bring the turret tools into cut in order, cut the thread with a die and part off, all in a fixed order and at fixed speeds^[7]. According to Roe, the most important invention was the "blank cam" drum, on which flat cam plates could be changed for each job, but it was not included in the patent claims, and Spencer could not secure rights to it. In 1876 Spencer founded the Hartford Machine Screw Co. and mass-produced screws on automatic screw machines^[2]. At Brown & Sharpe, too, S. L. Worsley built a fully automatic screw machine in the early 1880s^[2].

Cams are "the setup sheet inside the machine". The shape of an automatic's cams records which tool is fed, when, how fast and how far. Changing the setup became a job of making and fitting new cams, and skill moved from "the person who runs the lathe" to "the person who designs the cams and sets up the machine". An NC program is easiest to understand as these cams turned into numbers.

Hartness's flat turret lathe

Jones & Lamson, a descendant of Robbins & Lawrence, moved to Springfield, Vermont, in 1889, and James Hartness joined as superintendent. Until then, the company's main product had been a lathe with a lever-operated "high turret"^[2][12]. In 1891 Hartness brought out a turret lathe of a completely different form. The May 7, 1891 issue of American Machinist featured it on the cover as a machine that "completely abandoned the conventional form of turret"^[13]. The patent (US Patent 457,967) was applied for on January 9, 1891, and granted on August 18^[15][17].

On a slide like the carriage of an engine lathe sat a low, large disc (the flat turret), with the tool holders bolted to its top face. The disc was guided at its rim, and the locating pin was at the rim too, so the tools took the cutting force almost directly above the pin, without straining the central shaft. Each of the six tool holders had its own stop, so the end of the feed could be set for each tool. The work could extend over the top of the turret, so long, slender work up to 2 inches (about 50 mm) in diameter and 24 inches (about 600 mm) long could be turned on the turret^[13][14]. The American Precision Museum cites as advantages the wide spacing between tool holders, which allowed complex tooling, and the high rigidity^[14]. From Hartness's circle came the Fellows gear shaper (Chapter 9), Gridley's automatic, Fitchburg's Lo-Swing lathe and Bryant's internal grinder^[2].

Turrets for big work, and multi-spindle automatics

The turret ceased to be a tool only for small screws. Gisholt of Madison, Wisconsin, with designs by C. N. Conradson, extended the turret to large workpieces held in a chuck^[2][18]. For small parts, on the other hand, came the multi-spindle automatic, which machines several bars at once. Four to six spindles are arranged in a rotating spindle carrier (drum); each time the drum indexes, the work in each spindle moves on to the tools for the next operation. One part is completed at each index, so it could produce several times faster than a single-spindle automatic. At National Acme in Cleveland, E. C. Henn and R. Hakewessel, formerly of Pratt & Whitney, developed multi-spindle automatic lathes, and in Windsor G. O. Gridley's single- and multi-spindle automatics were built^[2]. Davenport, founded in New Bedford in 1894, long built the five-spindle Model B, patented in 1902^[21].

What changed on the shop floor. With turret lathes and automatic screw machines, screws, bolts and small parts for sewing machines, bicycles and cars went from "something machined one at a time" to "something run off on cams". On the other hand, setup took time, so they did not suit small quantities. "From how many pieces should a job go on a turret lathe or automatic?" has been a big question for job shops ever since this era.

Modernizing the engine lathe: gearboxes, electric motors and high-speed steel (1868–1920s)

From change gears to the gearbox

The 19th-century engine lathe was driven by a belt from an overhead line shaft; speeds were changed by shifting the belt on the steps of a cone pulley, and slow speeds came from back gears. To change the thread pitch, the change gears between the spindle and the lead screw had to be swapped set by set. In toolrooms that cut many kinds of threads, this swapping was a big chore^[23].

So devices appeared that arranged gears of different sizes in steps on a shaft and let one choose which to engage. Humphreys's patent of 1868 already had a "cone of gears", but the mechanism that spread as a product was W. P. Norton's^[6]. Norton's patent 470,591 of March 8, 1892 housed the stepped row of gears in a box, so the lead screw speed could be changed just by setting a lever. His 1894 improvement patent, 519,924, was assigned to the Hendey Machine Co. of Torrington, Connecticut, and became the Hendey-Norton lathe^[19][22]. Roe writes that Hendey shook the leadership of the Pratt & Whitney toolroom lathe, long the national standard, and that the gearbox spread to almost all machine tools^[2]. Perrigo's 1907 book compares the gearboxes of other makers side by side as well^[6].

Big lathes, and the lathe makers of Cincinnati

For heavy work, William Sellers of Philadelphia won an order in 1890, with his own design, for a lathe to turn the barrels of the Navy's 16-inch guns. It was a machine with an 8-foot (about 2.4 m) swing, weighing more than 500,000 pounds (about 230 t)^[2]. For medium-sized engine lathes, Lodge & Shipley and other lathe makers gathered in Cincinnati, where R. K. LeBlond had opened a shop in 1887^[9][10][11]. Lodge & Shipley was reorganized as a company on August 1, 1892, and in 1898 Davis & Egan renamed itself American Tool Works and stepped up its sales abroad^[20][24]. In Indiana, from 1906 the South Bend Lathe Works built small engine lathes and, through its textbooks for schools, First Year Lathe Work and How to Run a Lathe, spread the very way lathework was taught^[28][29].

Electric motors: the forest of belts disappears

Attempts to drive machine tools by electric motors began around 1892, and in 1895 the Baldwin Locomotive Works in Philadelphia converted its wheel lathes to individual motor drive. The aim was to remove the overhead line shafts and install cranes for carrying the heavy wheels^[23]. A British engineering magazine of 1902–03 showed motor-driven lathes by Lodge & Shipley in photographs^[11]. In 1907 Perrigo wrote that line shafts were fine for small lathes, but that lathes of 24-inch (about 610 mm) swing and over were better with individual motors, and gave an example of a lathe with a directly connected 1-horsepower variable-speed motor (500–1,500 rpm)^[6]. Even so, according to Ashburn, individual motor drive became the norm only in the 1920s, and line shafts lingered for more than 30 years^[23].

High-speed steel: the machines can't keep up

At the 1900 Paris Exposition, high-speed steel tools by F. W. Taylor and M. White of Bethlehem Steel cut steel at speeds that made the cutting edge glow red (120 feet per minute, about 37 m). The lathes and drilling machines of the Loewe company in Berlin, which took the tools home to try, were reportedly worn out in less than a month^[23]. Taylor and White's patent 668,269 was issued on February 19, 1901^[26]. With the carbon steel tools of the time, cast iron was cut at 20–25 feet (about 6–8 m) per minute and mild steel at 25–30 feet^[6].

Once tools could cut several times faster, it was the lathe that was too weak. Perrigo wrote that with high-speed steel, heavy cuts became normal, so headstocks had to be stronger, power greater and tool rests sturdier^[6]. A 1906 senior thesis at the Armour Institute of Technology in Chicago tested high-speed steel cutting on a Lodge & Shipley 16-inch "high-speed lathe" with a directly connected 2.5-horsepower variable-speed motor. Ten motor speeds and six gear steps gave 60 spindle speeds^[27]. The shift from cone pulleys and belts to geared headstocks and electric motors was driven by high-speed steel.

What changed on the shop floor. With the gearbox, setting up for thread cutting changed from "calculating and swapping change gears" to "looking at the chart and setting the levers". Electric motors and geared headstocks raised speeds, high-speed steel allowed deeper cuts and faster feeds, and the amount one lathe could cut in a day grew greatly. When looking at old lathe catalogs, "cone pulley or geared head" and "with or without a gearbox" are the easiest marks for telling a machine's generation.

Carbide, copying and war (1928–1954)

With carbide, once again "the machines can't keep up"

In October 1928, General Electric began selling sintered tungsten carbide tools under the name "Carboloy"^[32]. Carbide is much harder than high-speed steel and cuts faster, but it wears quickly at low speeds, chips if the machine lacks rigidity, and chatter is fatal to it. Lathes with 900 rpm spindles appeared quickly, but the Great Depression halted investment in machine tools, and 1930 shipments fell to less than half of the year before. Ashburn writes that a range of machines able to make full use of carbide finally became widely available only in 1939^[23]. As with high-speed steel, the tools advanced first, and lathes followed with thicker spindles, heavier beds and bigger motors.

War and the lathe

In July 1940, Presidential Proclamation No. 2413 put machine tools under export licensing, diverting them to domestic arms production^[33]. During World War II, Warner & Swasey of Cleveland employed 7,000 people and built half of America's turret lathes. Davenport of Rochester also received military priority ratings and built multi-spindle automatics around the clock^[8][21]. In work that machined large numbers of identical parts, such as shells, fuzes and aircraft parts, turret lathes and automatics were the main players (for wartime production as a whole, see Chapter 3).

Hydraulic and air-gauge copying lathes

After the war, Blanchard's idea came back as the "tracer attachment", to turn shapes such as stepped shafts quickly on engine lathes. Monarch of Sidney, Ohio, fitted its Series 60 engine lathe with the Air-Gage Tracer, a tracing attachment that moves the tool carriage by following a template. A 1949 trade journal reported an example in which three tracer lathes machined cast housings 3.75 times faster^[35][36]. Given a template, stepped shafts and shapes with tapers and radii could be turned without the operator working the feed handwheels one after another. Monarch had been incorporated in 1909^[30][31].

Precision lathes

In the opposite direction, for small, accurate work, Hardinge of Elmira, New York, built precision lathes for toolrooms and laboratories. The Hardinge HLV in a 1954 trade journal had an electrically driven, steplessly variable spindle and electric variable feeds for the carriage and cross slide, keeping the gearbox and lead screw for thread cutting only^[38]. Separating the feed from the lead screw and using the lead screw only for threading was a way to reduce lead-screw wear and preserve accuracy. Hardinge has built precision lathes since 1890^[39].

NC lathes and turning centers (1955–1979)

1955: a turret lathe run by paper tape

NC (numerical control) began as a technology for cutting complex aircraft shapes, as with MIT's NC milling machine of 1952 (Chapter 4). On lathes, Arma Corporation demonstrated a digitally controlled lathe in 1950, but it only attracted attention and won no orders^[23][37]. What actually took shape early on lathes was the turret lathe. At the Chicago machine tool show in September 1955, Jones & Lamson exhibited a prototype NC turret lathe. It read punched paper tape in binary code and commanded spindle speeds (two ranges of 16 steps each), the indexing of a hexagon turret and a square turret, a hydraulic collet chuck and bar feed, and even the coolant. The tools were preset to size with gauges in advance, so the pitch was that once commands were prepared from the drawing and punched into tape, parts could be cut without adjusting the tools^[40]. Using tape instead of cams to store the setup, even small batches could make use of the turret lathe's many tools.

1960: teach-in NC, and production models

In June 1960, Warner & Swasey announced the "Servofeed", an NC turret lathe with a 25-inch swing. Instead of preparing a tape, the operator taught it the good motions from a trial cut using push buttons (up to 96 commands), and the machine then repeated them^[41]. In December 1959 Monarch announced a Series EE lathe fitted with GE positioning NC^[42], and at the 1960 exposition American Tool Works showed a lathe that combined tracing with tape positioning^[45]. In 1961 LeBlond brought out the Tape-Turn, which moved the tool along a continuous contour^[46]. At the Chicago machine tool exposition in September of the same year, Jones & Lamson showed a production-model NC turret lathe^[44], and more than 100 NC machines were shown across the whole show. But the vacuum-tube controls could not take the heat wave in the halls, and many reportedly did not work well^[23]. Even so, NC machines installed in the US rose from a cumulative 193 through 1958 to 402 in 1960 alone, and in 1967 2,957 were built, accounting for 21% of the shipment value of metal-cutting machine tools^[23].

Japanese NC lathes and the microprocessor

In 1970, the NC lathe MTC-2500R of Yamazaki Iron Works (today's Yamazaki Mazak) became the first Japanese-made NC machine tool exported to the US^[50][51]. Around 1974, FANUC set up a service network in the US, and Japanese machines with FANUC NC units went on sale. FANUC was then making 3,000 NC units a year, approaching the total of all US makers (about 4,000)^[23]. The deciding factor was the microprocessor. In Japan, microprocessor-based CNC units appeared in 1976 and were fitted to small turning centers and machining centers for job shops. Independent US NC makers began using them only around 1980, and many US makers cited this four-year gap as a major reason for the surge in Japanese machines^[23].

Turning centers and slant beds

With CNC, the shape of the lathe changed as well. With its bed inclined, the slant bed lets chips fall away easily and puts the tool turret on the far side from the operator. The turret moves under CNC in two axes, and with live (rotating) tools fitted, the lathe can also mill and drill, becoming a turning center. Hardinge began building CNC machines in the late 1970s^[39], and at the Automated Manufacturing Research Facility (AMRF) of the National Institute of Standards and Technology (NIST), a Hardinge SuperSlant slant-bed turning center (3 axes, two turrets, 10-microinch resolution = about 0.25 μm) was at the heart of the turning station as of 1988^[58].

What changed on the shop floor. With NC lathes, setup changed from "making cams" and "making tracer templates" to "writing a program and entering tool offsets". Even small quantities could run automatically, and the wide range of work that lay between cam automatics and engine lathes moved to NC lathes. For how to write lathe programs today, see the NC programming page; for choosing tools, see the Tooling page.

★The import wave and restructuring, and CNC lathes today (1980–)

In 1984, NC lathes (horizontal and vertical) and machining centers accounted for 25% of US machine tool production value and 42% of import value. In 1985, more than two-thirds of the NC machines bought in the US were imports, and a few Japanese makers dominated small turning centers and machining centers. Ashburn writes that Japanese machines were smaller, lighter and cheaper, and at first broke down less often than American machines^[23].

One old lathe maker after another changed shape. The turret lathe maker Warner & Swasey was bought by Bendix in 1980 and went to Cross & Trecker in 1984; Giddings & Lewis, which absorbed that company, closed the last plant in January 1992, ending 110 years in Cleveland^[8]. In 1981 Makino Milling Machine bought LeBlond of Cincinnati, which became LeBlond Makino and, in time, the Makino Inc. of today^[54]. In NC units, General Electric, once a major US maker, formed a joint venture with FANUC in 1987 and soon stopped making its own NC units^[23].

The government acted too. On December 16, 1986, President Reagan announced voluntary restraint agreements (VRA) on machine tool exports with Japan and Taiwan. Japan was to restrain its exports to the US of machining centers, NC and non-NC lathes, punching and shearing machines and milling machines, and Taiwan those of machining centers, lathes and milling machines, for five years from January 1987^[56]. Japanese makers also chose to build in the US: Yamazaki Mazak has produced in Florence, Kentucky, since 1974, and Okuma in Charlotte, North Carolina, since 1987^[51][52][57]. The Florence plant marked its 50th anniversary in 2024 and builds more than 70 models^[53].

America's new face was Haas Automation, born in California in 1983. It started with a programmable indexer, and in 1988 brought out a vertical machining center for under $50,000^[55]. The precision lathe maker Hardinge bought the Swiss grinding machine maker Kellenberger in 1995, and its 2003 annual report shows it still building lathes at its Elmira plant^[39]. In May 2018 it was bought by the investment firm Privet for about $245 million and moved its headquarters to Berwyn, Pennsylvania^[59]. The multi-spindle automatic maker Davenport brought out the servo-driven Model B Servo in 1996, keeping the idea of cam-type machines alive today^[21]. For choosing and using lathes today, see the Lathes and Machining pages.

Links with Japan

Lathe building in Japan began on the British pattern and, at the end of the Meiji era, shifted to the American pattern. In 1903 the Tokyo Higher Technical School invited the American Charles A. Francis as an instructor in practical training, and in 1905 Ikegai built American-style lathes to his specifications and began volume production of the "Ikegai standard lathe"^[62]. Okuma (then Okuma Iron Works) bought the lead screw for its 1916 KE engine lathe from Brown & Sharpe, in 1918 launched the OS type, an improved version of the American Sebastian lathe, and in 1919 built the OP type from Pratt & Whitney lathe drawings handed over by an army arsenal. The design of its 1939 LT super-high-speed lathe drew on Monarch and other lathes^[63]. Until the US put machine tools under export licensing in 1940, more than 80% of Japan's machine tool imports came from the US^[34][33].

For postwar automatics, too, American machines were the model. When automatic lathe building was encouraged for the watch industry in 1948, Tsugami began building Brown & Sharpe-type automatics^[64]. Niigata Engineering introduced single-spindle automatic lathe technology from Sundstrand of the US in 1959^[65]. Eventually the flow reversed: Yamazaki Iron Works decided in 1962 to export 200 LE lathes to the US, sent the NC lathe MTC-2500R to the US in 1970 and began production in the US in 1974^[66][50][51]. The 1986 VRA put a cap on exports of Japanese NC lathes to the US, and around then Okuma also began production in the US (1987)^[56][57]. For events on the Japanese side, see the timeline of Chapter 1 of the Japanese archive; for the waves of Japanese machine imports, see Chapter 5.

FAQ

Who built the first turret lathe?

The oldest recorded example is a screw machine with an eight-tool, horizontal-axis revolving head built by Stephen Fitch of Connecticut in 1845. The first to build it as a product was Robbins & Lawrence of Windsor, Vermont, in 1854 according to Roe. The vertical-axis turret that later became standard came from drawings by the company's H. D. Stone.

When and how was the automatic screw machine born?

It began with Christopher M. Spencer's US Patent 143,306 of September 30, 1873. Cams arranged on a single shaft drove the bar feed, chuck, turret tools, threading and parting off in sequence, making screws without anyone touching the machine. Spencer founded the Hartford Machine Screw Co. in 1876 to mass-produce them.

What was new about Hartness's flat turret lathe?

It dropped the tall cylindrical turret of earlier machines, placed a low, large disc on a slide like the carriage of an engine lathe, and bolted the tool holders to its top face. Locating at the rim made it strong against cutting forces, and because the work could extend over the top of the turret, long, slender work up to 2 inches in diameter and 24 inches long could be turned on the turret. It appeared in 1891 and became Jones & Lamson's main product.

When was the first NC lathe in America?

Among the cases confirmed in this chapter, an early example is the Jones & Lamson NC turret lathe (prototype) shown at the Chicago machine tool show in September 1955. Using binary code on paper tape, it commanded spindle speed, turret indexing, the chuck and even the bar feed. In 1960, Warner & Swasey's Servofeed and Jones & Lamson's production model appeared.