Kärger

Kärger Lathes - Germany

G. Kärger of Kraut-Strasse 52, Berlin 0.27 were makers, from the late 1800s, of high quality machine tools including a range of precision plain-turning and screwcutting lathes designed for use in the watch, clock and instrument making trades. The models varied from simple bench models to very much more complicated examples for advanced work. The DP3, illustrated below, was a thoroughly well-made, V-bed lathe and typical of their products as manufactured at the turn of the 19th and 20th centuries. Whilst it closely reflected contemporary design for its type, it was a rather larger machine than those manufactured for the same purpose by makers in the USA such as Ames, Waltham, Stark, Potter, Rivett and Cataract - though very similar to models from Auerbach, also from Germany. Notable points that indicate a machine of quality (and one intended to help the professional user) include the large-diameter front headstock bearing, a 5-speed headstock pulley, well braced stand legs, a built-in storage shelf and locking cupboard, a long foot-treadle bar and a forged flywheel shaft running in independently-mounted bearing housings. So well made were these types that many continue in serious use today, being ideal for work that requires delicate manipulation of the tool slides. The plain lathes, and ones based on them, remained in the Kärger catalogue until at least theearly 1950s - and possibly longer - at which point they had been nationalised by the East German Communists under the banner of the WMW machine-tool organisation.
One important development for the company was the introduction, in 1892, of their first "precision leadscrew" models, the long-lasting DL Series. This came about as the result of Dr. Loewenherz, the director of the Physikalisch-Technischen-Reichsanstalt in Berlin (the P.T.R., an organisation similar to National Physical Laboratory in the UK) introducing a metric thread system (flank angle 53°8`), for use in precision trades such as watch making and political production. Needing a suitable lathe on which to turn micrometer screws, female micrometer screws and taps and other items needed to launch the new thread-system the P.T.R. turned to Kärger. For threading purpose the DL1 had a special spring-loaded and lever-operated support, to prevent the work from bending. There was also a simple but ingenious eccentric-operated slide system that permitted a quick retraction of the turning-tool as the end of the job was reached. The Loewenherz thread-system was quickly supplanted, in 1888, by the present metric (SI) thread-system with a flank angle of 60°.
During the middle years of the 20th century Karger's range developed to include more modern versions of the DL series, high-speed geared-head and production types and a range of unusual toolroom lathes with separate spindle-drive gearboxes in the base of their headstock-end plinths. The company exported their products world-wide both voluntarily, by normal commercial means, and after WW2 "involuntarily" when it is known that many, because of their high quality and durability, were seized as war reparations. For example, in the just-post-war years at the Standard Telephones & Cables Company's radio workshops at New Southgate, England, there were 5 Kärger lathes of about 6-inch centre height that had been brought over from Germany in this way.
If any reader can provide more information about the Kärger company and its products the writerwould be very interested to hear from you.

An early version of the Kärger logo

A 1920 Kärger, both motorised and with a treadle-drive, still employed on daily duties in the 21st century workshop of a German clock repairer.

The Kärger works at the end of the 19th century<img alt="" height="413" data-cke-saved-src="/sites/default/files/mainsite/images/03img-w_4.jpg" src="/sites/default/files/mainsite/images/03img-w_4.jpg" width="460">Circa 1910/1930 Kärger with chase screwcutting. The system used on this lathe was <a data-cke-saved-href="http://www.lathes.co.uk/karger/page2.html" href="http://www.lathes.co.uk/karger/page2.html">particularly ingenious</a> and employed the minimum number of parts. Like many lathes of its type the front face of the Kärger headstock pulley was fitted with circles of division holes--in this case a total of 12. The numbers are: 360, 168, 132, 102, 100, 96, 78, 54, 46, 38, 35 and 24. From these, using factors, it can be deduced that division into primes could also be made e.g. 38 =19 x 2, 46 = 23 x 2, 78 = 13 x 6, 102 = 17 x 6, 132 = 11 x 12. The primes could have been useful for locksmithing, codes or perhaps horology, where 29 and 31 might have proved handy to divide wheels for calendar motions - or for achieving various wheel ratios in a limited space. <img alt="" height="416" data-cke-saved-src="/sites/default/files/mainsite/images/04img-w_3.jpg" src="/sites/default/files/mainsite/images/04img-w_3.jpg" width="460">Almost the same Kärger as the colour photograph immediately above but fitted with treadle drive and much smaller micrometer dials<img alt="" height="904" data-cke-saved-src="/sites/default/files/mainsite/images/05img-w_1.jpg" src="/sites/default/files/mainsite/images/05img-w_1.jpg" width="460">A plain-turning Kärger lathe but fitted with a backgeared headstock <img alt="" height="617" data-cke-saved-src="/sites/default/files/mainsite/images/06img-w_1.jpg" src="/sites/default/files/mainsite/images/06img-w_1.jpg" width="480"> Kärger lathe fitted with a non-sliding headstock spindle, chase screwcutting of a traditional design and a large cross-feed handwheel to aid rapid parting-off of production parts. Note the weight to keep the threading tool in contact with the work piece. <img alt="" height="658" data-cke-saved-src="/sites/default/files/mainsite/images/08img-w_0.jpg" src="/sites/default/files/mainsite/images/08img-w_0.jpg" width="460">Kärger with a sliding headstock spindle lathe specially set up for high-speed milling and grinding operations <img alt="" height="409" data-cke-saved-src="/sites/default/files/mainsite/images/09img-w.jpg" src="/sites/default/files/mainsite/images/09img-w.jpg" width="480">Unusually for the time the Kärger had large and easily-read micrometer dials. This example is probably one of the last made during the 1930s<img alt="" height="542" data-cke-saved-src="/sites/default/files/mainsite/images/10img-w.jpg" src="/sites/default/files/mainsite/images/10img-w.jpg" width="480">A thick flat plate was dovetailed to the outside face pf the headstock and used to carry the thread chasing equipment. The section through which the headstock spindle passed was slotted to allow the plate to be moved up and down - by the action of a lever - and so engage and disengage the master thread and follower.<img alt="" height="656" data-cke-saved-src="/sites/default/files/mainsite/images/11img-w.jpg" src="/sites/default/files/mainsite/images/11img-w.jpg" width="480">Chase threading equipment mounted on the headstock end plate. The headstock spindle carries the master thread whilst, in this picture, the lever has been lifted to engage it with the bronze star follower. <img alt="" height="503" data-cke-saved-src="/sites/default/files/mainsite/images/12img-w.jpg" src="/sites/default/files/mainsite/images/12img-w.jpg" width="480">Headstock spindle extended fully forward showing the limit of its length threading capacity <img alt="" height="285" data-cke-saved-src="/sites/default/files/mainsite/images/13img-w.jpg" src="/sites/default/files/mainsite/images/13img-w.jpg" width="480">Headstock spindle extended fully forward showing the limit of its length threading capacitySource; <a data-cke-saved-href="http://lathes.co.uk/" href="http://lathes.co.uk/">lathes.co.uk</a> <table border="0" cellpadding="0" cellspacing="0" style="border-collapse: collapse; font-family: Times; font-size: medium;"><tbody></tbody></table>

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Kärger