ZDZ Watchmakers' Lathe
Other Lathes for Watchmakers
At the moment, just two makers of lathes for watchmakers and repairers have been identified as Polish: ZM Skarzysko and ZDZ, the latter based at 20 Friedleina Street in Krakow. ZDZ - the ZDZ Precision Machine Tool Company (Zaklad Doskonalenia Zawodowego) - are known to have made at least two models of watchmakers' lathe, both rather similar to those from ZM Skarzysko, the earlier of the two being the Type TDA-8. The lathe took 8 mm diameter collets with an overall length of 35.5 mm, a thread 7 mm x 0.5 mm, a thread length of 8 mm, a 1.8 mm width keyway and a head diameter of 12 mm. Drive came from 100W / 1400 r.p.m. motor that gave, using a 3-step headstock pulley, spindle speeds that spanned approximately 900 to 3600 r.p.m.. In later years the improved TDB-8 was introduced, this taking practically the same collets - but with a thread M7 x 0.75 mm - and drive from a 120W / 2750 r.p.m. motor to produce spindle speeds of around 1000 to 6300 r.p.m.
Of conventional "Geneva" design, the TDA-8 had a 20 mm diameter round bed with the flat at the back and headstock and tailstock clamped on using short levers to close down slots in their castings. The headstock spindle ran in large diameter, adjustable cone bearings - through with the addition of a ball race to take thrust, rather in the manner as originally employed on early Hammel, Riglander & Co. lathes. Lubrication of the bearings was possible, the maker providing either a pair of spring-sealed ball oilers or small screw caps. Collets were made by ZDZ themselves the rather fine 7 x 0.5 mm pitch thread making them useable only with the correct drawbar - though it is believed that some Lorch collets, together with the correct draw bar, could be used instead.
A number of accessories are known to have been offered including the usual range of collets and small fittings together with a proper screw-feed compound slide rest with a top slide having two longitudinal T-slots able to take the maker's 4-way toolpost. Clearly-engraved zeroing micrometer dials were fitted and the slide rest appears to have been of high quality. Also available was a lever-action tailstock with its spindle bored to accept collets.
It is believed that ZDZ also manufactured a high-quality, backgeared and screwcutting lathe intended for use by toolmakers - and details of this model can be found here. If you have a ZDZ lathe of any type, or literature about them, the writer would be interested to hear from you.