Gerbruder Thiel GmbH was based, originally, in Ruhla a small town in the Thüringen area of Germany and began as makers of pocket, wrist and toy watches and general metal products. The development of their famous machine tools began in the early 1900s, the initial aim being simply to supply their own factory with more efficient methods of production. Although the new products included a series of unique and long-lived filing and sawing machines, together with a specially developed metal cutting bandsaw, it was for their range of superb, very high quality universal millers that they were to become best known. The earliest such type, built in 1906, was intended for the manufacture of punches but by 1914 had developed into the much more useful and ingenious "Duplex" (the term indicating that the cutter spindle could be arranged anywhere from vertical to horizontal and the machine used for a variety of tasks). However, Thiel were not the only makers of such a model and in the United States Van Norman manufactured their own uncannily similar type, also called a "Duplex" (shown right, below the Thiel Duplex). Van Norman were handled in Germany by the well-known agents Schuchardt & Schütte, numerous examples appearing in their catalogues from 1899 to 1914. Hence, Thiel would have had the chance to see early examples of the type and either copied it, or were inspired by the design to make their own version. In addition, from the late 1800s onwards America had taken the world lead in outright production numbers and innovation in the machine-tool field - surely further circumstantial evidence that the German design sprang from an American drawing board.
By the early 1930s the very fine "Duplex 58" was in production - in which form the arrangement of its various components and controls provided such versatility that the success of the type was finally guaranteed. At the end of WW2, in 1945, Thüringen fell under Russian control and the works directors, the designers and many workers fled to West Germany where a factory was established at Leinfelden, near Stuttgart, In Ruhla the remaining workers restarted production (with some modifications) of the pre-war Duplex 58 - while in the West a new machine, the 158 was designed and built. It is also reported (but not confirmed) that Junghans, a firm of watch makers in the Black Forest, also built the Duplex 158. After some years the East German factory was renamed "VEB Ruhla" and a new model, the 59 introduced.
Heavily revised, the Type 158 had increased rigidity, had improved table travels, a wider speed range, built-in motor(s), improved electrical and safety controls, independent drive of spindle and table feeds, fixed dowelled positions for attachments and tables and hardened and ground feed screws. However, many accessories could be swapped over from the 58, as could collets and other spindle-nose fittings. The final conventional (non NC) Thiel miller made was the 162 - an improved "5-axis" machine that could perform all its tasks without the need to mount alternative tables or accessories.
The success of the "Universal Precision Miller" lay in ability to mount a number of different heads - horizontal, standard vertical, high-speed vertical and slotting - in combination with a variety of tables - plain, plain-tilting and compound swivelling. All the heads could be driven backwards and forwards across the top of the main column, by a handwheel working through reduction gearing, to provide an in-out feed, whilst the tables all bolted to a flat, vertical T-slotted knee equipped with power longitudinal and vertical feeds. By juggling the choice of heads and tables, and utilising other accessories, a skilled technician was seldom defeated in his attempts to produce the most complex of milled and drilled components - and all to a very high standard of accuracy.
Also illustrated on this page is the Model 58, a machine either copied or re-badged in the UK as the "EHJ-58" - "EHJ being the once well-known E.H.Jones Company of Edgeware Road, London. With their showrooms located in a busy area of north London, sandwiched between Hendon aerodrome, the British Museum Newspaper Library, the Frigidaire works and the DeHavilland aircraft company's Gipsy engine works, Jones were famous for their association with high-quality machine tools that were often, but not always of German origin
A slightly smaller 25" x 8.5" table was fitted as standard, this having three power feeds - longitudinally, in traverse and vertically - while power backwards and forwards was also fitted to the head. On some versions of the miller, fitted with a clutch, spindle speeds could be changed, or reversed, without stopping the cutter spindle. The head gearbox had three levers: that at the lower left gave forward - neutral - reverse whilst the other two levers were for speed changes by moving gears within the gearbox. The clutch engaging lever had three positions: left for high range - centre for disengaged - right for low range. Typically, with the LHS gear lever in its the central position, the RHS gear lever to its right-hand position and clutch in low range would give 105 r.p.m.--or 210 r.p.m. in the high-range setting.
A range of accessories was available including a dividing attachment, supplementary horizontal swivelling table, power down-feed to the spindle, slotting attachment, self-contained high-speed (5000 rpm) vertical head attachment, and the usual range of vices and precision setting and measuring equipment. The whole machine was remarkably similar to, but much larger than, the much copied Deckel** universal miller - and, because of their unique features and superb quality of construction many examples of both types are still to be found doing experimental and development work, nowadays often in the hands of highly skilled, self-employed engineers.
After WW2, Thiel was split into two parts with one based in the Allied-controlled Federal Republic of Germany and the other in the communist-controlled German Democratic Republic.