GERMANY 05The Lineage of German Lathes

From British models to Chemnitz lathes (c. 1826–1890)

German lathes started not as products for sale but as tools that machine shops made for use in their own works. In Chemnitz, Saxony, the spinning machinery works Haubold built machine tools for its own shop in 1826, and Richard Hartmann, maker of locomotives and spinning machinery, began doing the same in 1842^[1]. From there emerged works that specialized in building machine tools for sale. Johann Zimmermann, a Hungarian-born locksmith, became sole owner in 1848 of a works he had started with a partner in 1844, and went on to build shapers, planers, drilling machines and lathes. He is the man later called “the father of German machine tool building”^[1][2].

36 lathes with slide rests

The 1856 Album der Sächsischen Industrie presented Zimmermann's new works as a “model factory.” A single 30 hp steam engine turned the overhead line shafts, and under them, alongside 20 planers, slotting machines, drilling machines and gear dividing machines, there were 36 iron lathes with slide rests (Supportdrehbank). One of them could cut a lead screw 47 feet (about 14 m) long. The album says 250 people worked there, and engineers who had been buying machines from Britain were starting to switch to this works' machines^[3].

An encyclopedia figure of 1906 conveys the mechanism of lathes of this period well. The spindle was driven from the overhead line shaft by a cone pulley (a stepped belt pulley), and speed was changed by shifting the belt, while slow speeds came from the headstock's gear reduction (back gear). The tool was not held by hand but clamped in a slide rest (Support) with two slides, and for long work the slide rest was fed by a lead screw (Leitspindel) and change gears, which also cut threads. Some lathes came with as many as 60 change gears^[15]. Handing over to the machine's feed the cutting that had depended on manual skill: this was the core inherited from the British lathe.

Chemnitz becomes a center

Zimmermann's machines won a gold medal at the 1862 London International Exhibition, and at the 1867 Paris Exposition he and Hartmann both took gold medals. By 1868 the works had about 1,000 workers and 160 lathes in its own shops, and it shipped three-quarters of the machine tools it made to Russia, Austria, Britain and South America^[1]. By around 1860 the works of Hartmann, Zimmermann, Diehl, Sondermann & Stier and Reinecker stood side by side, and Chemnitz had become the center of German machine tool building. In 1880 Sondermann & Stier built about 4,000 machines a year in 89 types^[1].

Among lathes, Reinecker's relieving lathe (Hinterdrehbank) was distinctive. It relieves the back of a milling cutter's teeth little by little while keeping the shape of the cutting edge, so cutters made this way keep their shape when resharpened. Reinecker showed relieved milling cutters at the 1873 Vienna World's Fair and from 1882 also sold the relieving lathe itself. It was work modeled on American machines^[1][7]. As for large lathes, by 1910 Zimmermann had built lathes with 24 m between centers at the largest^[1].

Turret lathes, automatics and high-speed steel (1869–1914)

An ordinary lathe cuts while the tools are changed one at a time. If you are making hundreds or thousands of the same part, why not set up all the tools beforehand and bring them round in turn? That is the turret lathe (Revolverdrehbank in German). Turn the head holding the tools (the turret) to the next station, feed it up to a stop, and even a worker who is not highly skilled turns out parts of the same size. The idea was brought into Germany by two men, in Berlin and Leipzig.

Loewe: an American-style factory

Ludwig Loewe was a merchant, neither craftsman nor engineer. He founded his company in Berlin in 1869–70 and toured the US in 1870. He learned from American factories that concentrated on a single product and made it in large quantities with special machines and interchangeable parts, and from 1873 he began selling machine tools to other factories too^[4][5]. In 1896–98 he built a new machine tool works in Berlin-Moabit, bringing in three American engineers to set it up as a factory for interchangeable manufacture. The young Georg Schlesinger, who joined in 1897, started as interpreter for the American engineers and went on to coordinate the preparation of jigs, gauges and standard models such as lathes, turret lathes and milling machines. Its approach of building a few models in quantity for stock has been described as anticipating the post-World War I “rationalization” by 20 years^[5][13]. Schlesinger later became a professor at TH Berlin and turned machine tool accuracy testing into an academic discipline (see Chapter 2).

Pittler: the 16-hole turret

Wilhelm von Pittler of Leipzig was an inventor of sewing and embroidery machines. In 1888 he built a universal metalworking machine with six uses, in 1889 founded Maschinenfabrik „Invention“, and in 1890 built a lathe with a turret. The turret at first had 6 tool holes, increased to 16 from 1894^[9]. On February 24, 1893 he filed German patent 74951 for a “metalworking machine with turret”^[11]. His first big customer was Ernst Sachs of Schweinfurt, who made bicycle hubs and bought more than 100 machines. Bicycles were one of the first industries to mass-produce with interchangeable parts^[9].

Hülle's 1919 textbook presents Pittler's “multi-hole turret lathe” as a machine with a rugged box-section bed and a 16-hole turret, whose tools could be combined in many ways^[14]. Pittler's company became a joint-stock company in 1895, moved to a new works in Leipzig-Wahren in 1899, and from 1901 also built semi-automatic and automatic lathes (single- and multi-spindle automatics) modeled on American machines. These machines let one worker tend several lathes^[10].

Automatics: teaching the sequence to cams

Even on a turret lathe, a person still turns and feeds the turret. Having the machine do that as well gives the automatic screw machine. The 1919 textbook describes Loewe's automatic turret lathe as a machine in which “cam drums and cam disks on a single control shaft move, in order, the feed and return of the turret, the indexing, and the advance and retreat of the slides”^[14]. The shape of the cams is the machining sequence itself, so when the part changes, new cams are made. Setup takes effort, but once it is running it turns out one part per cycle, the same part every time, even with nobody standing by.

Going further, the machine that cuts several bars at once is the multi-spindle automatic. Gildemeister of Bielefeld (founded 1870), under Wilhelm Berg from 1906, narrowed its range to multi-spindle automatics and drum-type turret lathes^[6]. The 1919 textbook shows Gildemeister's four-spindle automatic, which cuts four bars at once on four spindles^[14]. And in 1914, in Esslingen, Hermann Hahn founded Index and built the cam-operated automatic “Index I.” The company name came from the indexing (Indexieren) of the turret^[18][19].

High-speed steel and the electric motor: the headstock changes

Shown by the Americans Taylor and White at the 1900 Paris Exposition, high-speed steel changed the way German lathes were built from the ground up. Lueger's technical lexicon of 1914 says progress in lathes was pulled along by high-speed steel. Cutting faster meant more spindle speed steps and sturdier parts throughout: cone pulleys were widened, small steps avoided, and back gearing increased from one stage to two or more. Many new machines had taken the form of being driven by a single belt or an electric motor, with speeds changed by a gearbox inside the headstock, it says^[17]. The example it gives is the precision high-speed lathe of Boehringer of Göppingen, with a motor mounted on the headstock. Boehringer says it built the first electrically driven lathe in 1896, and from 1905 it concentrated on lathes^[12]. How much high-speed steel shook German lathes also shows in the story of Loewe's trial told in the chapter on American lathes.

Large lathes were changed by the electric motor too. The 1906 encyclopedia illustrates a vertical lathe by Schiess of Düsseldorf (up to 9.5 m in diameter) whose table was driven by a motor of about 25 hp in 20 speed steps from 0.09 to 4 rpm. It says the machine was driven by its own motor so that it could run through the night with almost no one attending^[15]. Lueger's 1914 lexicon includes a Schiess vertical lathe with a faceplate 11 m in diameter, weighing 300 t^[17].

What changed on the shop floor. With turret lathes and automatics, lathe work split from “a skilled turner matching sizes one part at a time” into “a setter matching tools and cams, then leaving the rest to the machine.” That deciding how to lay out the tools and in what order to run the operations is still at the heart of setup on today's CNC lathes is a continuation from this period.

Single-belt headstocks, carbide tools, VDF and war (1914–1945)

In World War I, the lathe became a machine for cutting shells and gun barrels. Boehringer built shell-turning machines and lathes for boring gun barrels^[12]. Since before 1920, Pittler had proclaimed on its letterhead that it was “the leading specialist works for turret lathes and automatics on the Continent”^[10].

The lathe in the 1919 textbook

The 4th edition of Hülle's textbook (1919) describes the mechanism of the lathes of this period in detail. Spindle speed was changed by driving a gearbox from the overhead line shaft or an electric motor through a single belt that is never shifted (Einscheibenantrieb) and changing the combination of gears^[14]. On Boehringer's high-speed lathe, a 20 hp multi-speed motor (a motor whose speed can be changed in steps) gave 400–1,400 rpm in five steps, which gears then extended further^[14]. Loewe's engine lathes and roughing lathes and Boehringer's heavy turret lathes are also explained with illustrations. Cone-pulley lathes with belts shifted by hand were giving way to lathes whose gears were changed with levers.

The rigidity carbide tools demanded

In the late 1920s, another big change came on the tool side: Krupp's carbide tool “Widia.” The name comes from “wie Diamant” (like diamond); the trademark was filed in December 1925, registered in May 1926 and shown publicly at the 1927 Leipzig fair^[20][21]. Carbide tools cut much faster than high-speed steel, but their edges chip easily and they hate vibration. Lathes were now required to have faster spindles and thicker, heavier beds and headstocks (for the history of carbide tools, see Chapter 2).

VDF: building by size

In 1928 four companies, Boehringer of Göppingen, Wohlenberg of Hannover, Heidenreich & Harbeck of Hamburg and Franz Braun of Zerbst, formed a joint manufacturing and sales association, VDF (Vereinigte Drehbank-Fabriken, United Lathe Works). Each company took a range of lathe sizes, and they sold lathes built on the same principles. In the middle of the Great Depression, more than half of VDF's exports went to the Soviet Union^[12]. In 1934 a Moscow factory was displaying machines modeled on VDF's geared-head lathes^[24]. Material from Japan's National Museum of Nature and Science describes VDF lathes as machines based on Schlesinger's research^[25].

On the automatics side, Index called itself “Index Werke Hahn & Kolb” in a 1934 patent and “Index Werke” in a 1937 patent for automatic lathe cams^[58][59], showing it kept refining cam-type single-spindle automatics. Around 1938 Hermann Traub's company started in Reichenbach an der Fils^[28], and also in 1938 Weiler, later known for training and toolroom lathes, was founded^[26]. Escher of Chemnitz was sold in 1930 to Deutsche Niles-Werke of Berlin and, as Niles's Siegmar works, built lathes, vertical lathes and horizontal boring and milling machines^[8].

The second war

Pittler, which celebrated its 50th anniversary in 1939, was that year the largest turret lathe maker in continental Europe^[30][10]. By 1934 it had also acquired 75% of the shares of a Magdeburg machine tool company^[23]. Orders for lathes to cut parts for guns and shells drove sales up; the works began retraining women and put many foreign and forced laborers to work^[10]. The air raids of March 1945 destroyed almost all the machine tool works in Chemnitz, but Niles's lathe works survived and after the war built lathes for reparations under Soviet control^[1][8]. Pittler's main works in Leipzig was seized and dismantled, and Gildemeister's works in Bielefeld was destroyed in air raids too^[10][6]. For the war and the division as a whole, see Chapter 3.

Lathes in East and West: copying, punched cards and heavy lathes (1945–1970)

After the war, German lathes split into East and West. In 1948 Pittler's directors and managers founded Pittler Maschinenfabrik AG in Langen (Hesse) in the West and rebuilt turret lathe production in a new works^[10][9]. In Leipzig in the East, the state-owned VEB Drehmaschinenwerk Leipzig (DREMA) was formed from Pittler's seized assets^[33]. A foundry and machine works in Bautzen made a fresh start as EMAG in Eislingen in the West in 1952 and began building lathes and special machines^[37][38].

Copying lathes: cutting by tracing a template

When turning hundreds of multi-step shafts, measuring and stopping at each step is laborious. What spread as a result was the copying lathe. A stylus traces a template (or a master part) of the same shape as the work, and that motion is amplified hydraulically so the slide follows it, making the tool trace the same contour as the template. Boehringer filed for a “lathe with a copying slide (Nachformsupport)” in December 1951^[36], and the same year also filed for a lathe for turning the pins of crankshafts (the off-center journals)^[35]. Mass production of automotive parts demanded that lathes “cut right down to the shape in one setup.” EMAG too filed in 1975 for a hydraulic copying lathe that even cut threads with cams and templates^[46].

VDF continued after the war. A lathe patent Boehringer filed in 1949 lists engineers from Hannover and Hamburg as inventors alongside those from Göppingen, suggesting that the VDF partner works were designing together^[32].

Turret lathes run by punched cards

An English catalog of VDF's RS 50–RS 100 turret lathes from around the late 1950s conveys the mechanisms of this period well. A turret lathe operator performs as many as 6,000–10,000 operations in eight hours, tires, and makes more rejects. So VDF had a punched card switch spindle speed, direction of rotation and feed automatically. The cards were prepared in advance by the factory's planning department, cutting manual operations by about 30%, the catalog says. Speed changes were made by electromagnetic clutches in the headstock, leaving only one lever, for switching to the belt drive for the high-speed range. The bed was wide, with two hardened and ground V-ways, and chips fell down between the ways. The spindle nose conformed to the DIN short taper standard^[22]. Even before NC, the lathe was already moving toward “the machine reading a sequence written on paper.”

Gildemeister launched the RV 50 turret lathe in 1950 and added multi-spindle automatics for bar work and chucking work in 1951^[6]. In 1950 it filed for a device that switched spindle speeds electro-hydraulically in step with turret indexing^[34], and in 1966 for a multi-spindle automatic with the cam control shaft moved above the longitudinal slide block^[41]. In 1970 it bought Heidenreich & Harbeck of Hamburg, one of the VDF companies^[6].

Heavy lathes in the East: “8. Mai” and DREMA

In East Germany, the former Escher/Niles works in Chemnitz was renamed “VEB Großdrehmaschinenbau „8. Mai“” (Heavy Lathe Works “May 8”) on May 8, 1953. Building lathes, vertical lathes and horizontal boring and milling machines, the works was said to be the largest lathe maker in the Eastern economic bloc in 1950^[8][1], and in 1978 it exported more than 70% of its output^[1]. In 1969–70 the works making machines for rotational parts were brought together in the “7. Oktober” combine in Berlin, which “8. Mai” and DREMA of Leipzig also joined. Machine tools were exported under the state WMW name, and promotional photos labeled “WMW” survive in the state archives^[8][33][1]. In East Germany NC lathes were built from 1963 and NC slant-bed lathes from 1967, and the ROTA F 125 NC, an NC machining system for rotational parts, appeared at the 1971 Leipzig Spring Fair^[1][8].

From NC to CNC and turning centers (1955–1990)

The story of NC (numerical control) begins at MIT in the US, but Germany followed it early. Herwart Opitz of WZL in Aachen sent a staff member to MIT in 1952, and in 1955 showed a model of a homemade NC machine at a research meeting in Aachen. At the 1960 Hannover Messe, German makers lined up NC machines^[39]. In the same year, 1960, Siemens launched an NC unit fit for the shop floor, and in 1964 it gave it the name SINUMERIK^[40]. For the overall story of NC, see Chapter 4.

Feeds on early NC lathes: pulses and hydraulics

According to an encyclopedia of company histories, Gildemeister showed its first NC lathe, the RSA, in 1965 and put it on sale in 1967^[6]. The feed mechanism of NC lathes of this time is well shown in a 1969 Gildemeister application, titled “Feed drive with an NC-controlled electric stepping motor and hydraulic amplifier.” A stepping motor, which turns a little at a time with each pulse from the NC unit, is weak, so its motion was amplified hydraulically to drive the lead screw and slides^[42]. In 1971 it also filed for an “NC lathe with a cross slide”^[60].

Indexing the spindle: the seed of the C-axis

Essential to the turning center (a lathe that also drills and mills with driven tools besides turning) is the C-axis, which stops the spindle at any angle. In December 1972 Index filed for an NC lathe whose spindle rotation was linked to the NC so it could be indexed and stopped at set angles (US patent 3,878,742)^[45]. At the same time, Index's cam-type single-spindle automatics reached their 40,000th unit in 1971, and the company was still filing patents to improve cam-operated slides^[18][44]. Cam machines were cheap and fast, and still the mainstay for parts made by the tens of thousands.

In 1977 Gildemeister launched its own CNC, the Elektropilot, and built multi-spindle automatics controlled by microprocessors. Around the same time, EMAG began selling CNC lathe cells that load and unload parts automatically around the world^[6][37]. In 1979 Traub filed for a method on NC lathes of measuring and setting the position of the tool tip relative to the tool carrier. It reduces the work of matching sizes by trial cuts every time a tool is changed, a technique that leads to today's tool offsets and tool presetting^[47]. Index launched a CNC turning and milling machine in 1983 and a CNC multi-spindle automatic in 1985 (the company calls both world firsts)^[18].

In 1988, NC lathes made up 74.6% of the value of lathes produced in West Germany. In Japan the same year the figure was 89.5%, and Japan accounted for about half of world NC lathe production, followed by West Germany and Italy^[48]. In the 1980s, West German lathe makers found themselves competing head-on with Japanese NC lathes.

Pick-up lathes and restructuring (1990–)

The vertical pick-up lathe: the spindle goes to fetch the work

In 1992 EMAG turned the lathe upside down. It hung the spindle facing downward and moved the whole spindle in the X and Z directions. The spindle grips a blank on the conveyor in its own chuck (pick-up), carries it over stationary tools arranged below and cuts it, then sets it down when finished and goes to fetch the next one. EMAG calls this the world's first vertical lathe in which the spindle moves along the main axes^[51][38]. In April 1992 it filed a patent for a machine with a motor spindle on a cross slide that even integrated chip and coolant collection and measuring devices (also filed in Japan and elsewhere)^[52]. The idea came from Norbert Heßbrüggen, who became technical director in 1969 and bought the company in 1975^[43].

This layout has several advantages on the shop floor. Since the machine loads and unloads the parts itself, a single machine becomes an automated machining cell as it is, with no separate loader. Since the tools are below the part, chips fall away unhindered. The workpiece flow can be arranged from either the left or the right, so lines of machines are shorter^[51]. The bed is not cast iron but cast from reaction-resin concrete (polymer concrete), and in 1991 EMAG had also filed for a lathe with this one-piece bed^[50][51]. Around 2017, when the company marked its 150th anniversary, more than 12,500 pick-up lathes were in use worldwide^[37][43]. The idea of a vertical spindle was not EMAG's alone: in 1990 Gildemeister also filed a European application for a vertical lathe in which up to four workpiece spindles move on their own guideways^[49].

Restructuring: Index and Traub, Pittler and EMAG

The 1990s were a time of consolidation among lathe makers. In 1997 Index bought Traub in the neighboring town of Reichenbach and formed a group that kept both the Index and Traub brands^[19][18]. In the East, DREMA of Leipzig was privatized in 1990 and became Pittler-TORNOS in 1991^[33], but it went bankrupt in 1997, and in September 1999 EMAG took it over as EMAG Leipzig^[53][37]. “8. Mai” in Chemnitz was taken over by NILES Drehmaschinenbau in 1993^[8]. In 1994 Gildemeister acquired most of Deckel Maho, becoming a group with both lathes and machining centers^[6]. Boehringer, the core of VDF, changed hands from Oerlikon-Bührle (1973) to IWKA (1987) and MAG (2006), and joined Taiwan's Fair Friend Group in 2013^[12].

Lathes also moved toward finishing a part on a single machine. EMAG launched the VSC 250 DDS, which turns and grinds on one machine, in 1998^[37], and Index launched a CNC turning and grinding machine in 2002 (the company calls it the world's first)^[18]. The overall story of multitasking machines is told in the Japanese Archive's Chapter 7, “The Lineage of Multitasking and 5-Axis Machines”.

Today's lineup

The main German lathe makers today include DMG MORI in Bielefeld (formerly Gildemeister), Index and Traub in Esslingen and Reichenbach, EMAG in Salach, the Niles line in Chemnitz, and Weiler, maker of training and toolroom lathes (head office moved from Herzogenaurach to Emskirchen in the 1990s)^[27]. Index, which turned 100 in 2014, had about 2,200 employees worldwide and sales of about 450 million euros^[19].

Links with Japan

Japanese lathes learned a great deal from VDF before the war. From 1935 to 1956 Ikegai Iron Works built engine lathes modeled on VDF lathes, with the headstock and feed boxes made as units. According to the National Museum of Nature and Science, standard lathes, single-purpose lathes, facing lathes and turret lathes could be mass-produced from combinations of the same units to meet the military's varied orders, and they were groundbreaking for their time in accuracy, heavy cutting and durability alike. One built in 1937 survives at the Nippon Institute of Technology^[25]. Okuma Iron Works also referred to VDF lathes, alongside American lathes, when designing its Model LT ultra-high-speed lathe in 1939^[31]. Both are also listed in the timeline of Chapter 1 of the Japanese archive.

After the war, the two countries became competitors and partners. In 1988 Japan produced about half of the world's NC lathes, with West Germany second^[48]. In 2009 Gildemeister and Japan's Mori Seiki formed a business and capital alliance; in 2013 both companies took the DMG MORI name, and in May 2015 the Japanese side came to hold 52.54% of the German side's shares^[54][55]. A Bielefeld company that started with multi-spindle automatics and turret lathes and a Nara company that switched from textile machinery to lathes had become one group. EMAG's basic pick-up lathe patent was also filed in Japan^[52].

FAQ

What is the difference between a turret lathe and an automatic?

A turret lathe is a lathe with a head (the turret) holding several tools, which is turned to use the tools one after another; feeding and turning the turret are done by hand. An automatic is a lathe that leaves even those operations to cams (later to NC), repeating the whole cycle from feeding the bar stock to finishing and cutting off the part without an operator. In Germany, Pittler and Loewe spread the turret lathe, and Pittler, Gildemeister, Index and Traub spread the automatic.

How did VDF lathes influence Japanese lathes?

VDF was a lathe association formed in 1928 by Boehringer and three other companies, which divided the size ranges among themselves and built a line of lathes on the same design principles. From 1935 Ikegai Iron Works modeled its engine lathes on VDF lathes, making the headstock, feed box and other parts into units so that a variety of lathes could be mass-produced by combining the same units. Okuma Iron Works also drew on VDF in designing its LT type of 1939.

How is EMAG's pickup lathe different from an ordinary lathe?

On an ordinary lathe, the spindle that turns the work stays put and the tool is fed to cut. On the vertical pickup lathe EMAG built in 1992, the downward-facing spindle itself moves, picks up the blank on its own, and cuts it over fixed tools arranged below. One machine can load and unload parts without a separate loader, and with the tools underneath, chips fall away easily.

Which was the first NC lathe in Germany?

No source has been found that lets us say “this one machine was the first.” In 1955 the WZL in Aachen showed a model of an NC machine, at the 1960 Hannover Messe German makers exhibited NC machines, and Gildemeister is said to have shown its RSA NC lathe in 1965 and put it on sale in 1967. In East Germany, NC lathes were built from 1963. This chapter gives each of these within the limits of what its source says.