A full catalogue is available for Georg Jacob lathe
Made in the GDR - the Communist-controlled former East Germany - the 8 mm watchmakers' lathe branded as a "Georg Jacob" was, in reality, made by Andr?/a> & Zwingenberger and of the lighter Geneva type. The lathe was also sold in various forms with other East German branding, including the WMW "Prazima" in model types that including the Z1, Z2, Z3, Z4 and Z5. Finally, further modified as to their drive systems and other details, by the 1970s they were being listed as by Saupe & Sohn of Georgstrabe 45, D-09207 Limbach-Oberfohna.
Although some Andr?& Zwingenberger lathes closely resembled the Georg Jacob, with some stamped as if by G. Boley, the one shown below has a number of differences - though as might be expected, various accessories, including the screw-feed compound slide rest were identical. Like all of its type, the Jacob was available with a wide range of extras, these usually being supplied in a fitted wooden box that, because its main aim was as a gatherer of foreign currency, would have been in a comprehensive yet competitively-priced form. Listed by both Georg Jacob and Andr?& Zwingenberger, the boxed set was sold under the same part number, 15363, though the boxes and their contents were not the same. However, the main items included in both consisted of a screw-feed compound slide rest, a self-centring 3-jaw chuck with screw-on reversible face jaws, faceplate with clamps, a set of wire collets from 0.3 to 7 mm in increments of 0.1 mm, five cone and five fir-tree collets, a box chuck, two tailstocks one to take runners (a set was supplied) and the other with either a lever or screw-feed spindle, a lapping attachment, wax chucks, flip-up and fixed hand T-rests, both single and double-roller filing rests, a miniature saw bench, saw-holding arbor, a safety pulley for turning between centres and various arbors.
A number of other items, at extra cost, were also listed, including a hand-cranked countershaft unit for bolting to the bench and, a most useful addition, a kit of parts to convert the lathe into a precision drilling machine that consisted of a base casting, jockey pulleys, a two-pulley bench-mounted guide for the belt drive and a round drilling table to fit into the tailstock. One unusual - indeed, possibly unique accessory- was an assembly of parts that, at least to English-speakers, might raise a smile, the "Winkelwange". The unit consisted of a hinged bracket, formed with two sockets one of which clamped over the tailstock end of the bed. Into the second socket could be fitted another section of bed bar and, mounted on this, the screw-feed compound slide rest to which was fastened a high-speed grinding and milling spindle driven - instead of by a traditional "overhead" - from a pulley on the end of an extended motor shaft. As the whole assembly could be hinged from horizontal to vertical, it allowed the operator to mill or grind material held by spindle-mounted fitting, a 3 or 6-jaw chuck, collet or faceplate. Other major extra included all-lever-feed to the headstock collet closer, cross and top slides and tailstock - the set-up being marketed for production use - a 6-jaw self-centring chuck and alterative sets of wire, cone and stepped collets for the headstock and small-diameter ones for the tailstock.
Of otherwise quite ordinary specification, the Georg Jacob was mounted on a rectangular cast base supported on four rubber feet, an arrangement that mirrored the practice of other makers of similar machines from the late 1940 onwards including Pultra and IME in England and Leinen in Germany, all of whom fitted a lathe in the "vintage style" on a mount with an integrated drive system. However, in the case of the Georg Jacob (and other versions of the lathe) "integrated" was, perhaps, pushing the boundaries of the word as the motor was simple hinged on the left-hand end of either a front or rear mounted bar, each of which passed horizontally through the casting. According to the requirements of the job (and bearing in mind the need to drive the Winkelwange) the motor could be set to hand either forwards or backwards.
As the Georg Jacob is, in many ways, very similar to the Andr?/a> & Zwingenberger, if you have an example of this type, the large set of pictures (over several pages) devoted to the latter model are well worth examining..