email: tony@lathes.co.uk
Home   Machine Tool Archive   Machine-tools Sale & Wanted
Machine Tool Manuals   Catalogues   Belts   Books   Accessories

lathes.co.uk
VDF 18RO, 21RO and 24RO Lathes - Germany

A comprehensive Manual is Available for the
VDF 18RO, 21RO and 24RO Lathes in English and German

"Vereinigte Drehbank Fabriken" (VDF) was an organisation designed to assist the engineering and sales effort of a group of German machine-tool manufacturers including: "Heidenreich & Harbeck, Hamburg", "Boehringer" and "Wohlenberg, Hannover".
This "Association" of independent makers created a unified design of lathe and shared in world wide marketing with offices in Frankfurt/Main. The lathes appear to have been marked using either the maker's alone, or with just a VDF label - or with both a maker's and a VDF badge.
Although the companies benefited from cross fertilisation of ideas and common research (as many automobile companies do today), each plant continued to build its own range often in size and specification similar to those made by others in the group.
In addition, many machines enjoyed what might be called a flexible specification, being built to a customer's specific requirements - one example being the basic versions intended for repetitive work on parts of limited size. These models were usually bereft of a tailstock and fitted with headstocks and feed gearboxes that had just four rates of speed and feed respectively - though the makers did offer to change this set-up if required. While strong, accurate lathes, they are obviously not as capable as the regular versions and are quite unsuited to general workshop tasks; in reality, few survive for, once worn out, they would have been scrapped. Many models were also offered with a choice of a plain bronze or roller front bearing, the former sometimes favoured by toolrooms where accuracy was considered more important than very high speeds. However, the only drawback to a plain lathe for general use is the expense and difficulty of finding and fitting up parts - a roller-bearing model is, in comparison, very much easier to keep running as bearings should be available off the shelf.
Text continued below:

Some pictures are high resolution and may take time to load


Heidenreich & Harbeck 18RO, 21RO and 24RO lathe

Continued:
Built by Heidenreich & Harbeck of Hamburg, the smallest models in the VDF range were the 18RO 21RO, and 24RO with centre heights of 7" ((180 mm), 8.25" (210 mm) and 9.5" (240 mm) respectively. The 18RO and 21RO could be had with between-centres capacities of 500, 750, 1000, 1250, 1500 and 2000 mm (19.625, 29.5, 39.375, 49.25, 59 and 79.75 inches) and the 24RO could be ordered with one extra length capacity of 2500 mm (98.5"). Long-bed versions were fitted with a third foot in the middle of the bed to prevent sagging when under a heavy load
While the RO18 and RO21 were designed and built to handle work within their size capacity, the RO24 was a "stretched" version intended for larger, lighter or more awkward jobs where rates of metal removal were not an important factor - with the added benefit of freeing up heavier machines in a busy shop for their intended purpose. However, although otherwise having the same general specification of the smaller models, the 24RO was, to help its intended purpose, equipped with a stronger saddle and cross slide.
Both standard and models with increased accuracy were available, the latter ) to the DIN standard 8605 but on straight-bed lathes only (i.e. without a gap) and up to 39 inches (1000 mm) between centres These superior models could be had with or with a high-precision leadscrew, this being made to a guaranteed maximum pitch error of just 0.0008" or 0.0004" over 12 inches (0.02 mm or 0.01 mm over 300 mm) Whether the increased accuracy was the result of more careful machining and assembly - or just the selection of the most accurate machines from a standard production batch (as Colchester did with some of their lathes) is not known, but, being a cynic, the writer would suggest the latter as being more likely.
First in the range to be put on the market was the RO18, introduced during the late 1940s followed by, in the very early 1950s, the RO21 and then the RO24. The lathes remained largely unchanged until around the early 1960s when numerous improvements were made, these including an increase in weight of around 8%, the fitting of needle-roller bearings in place of plain bushes on shafts such as lever pivots and modifications to the headstock and its lubrication system.
Motor power varied, the makers suggesting from around 5 to 10 h.p. being necessary, the early standard models listed as needing 5.5 h.p. while publicity material hinted that later versions really needed 7.5 h.p. Fitted with a No. 4 Morse taper on all versions, on early models the headstock spindle was bored through 50 mm and fitted with DIN800 threaded nose, later machines being larger at 56 mm and usually found with the much more supportive and safe short-taper DIN 55022 - this using the same angle as the well-known American-designed CamLock type.
While it is believed that the models made in the 1940s and early 1950s had two plain spindle bearings, all others had a double-row taper roller at the front and a single row at the rear - though the option did remain to have an adjustable plain bearing at the front; axial thrust was taken by a ball race. Gears were built into the headstock, made of a special alloy steel, heat treated, ground finished and held on multi-spline shafts running in roller bearings. Control was by two levers, one mounted on the headstock, the other pivoting from the right-hand face of the apron and travelling with it. Both were of the safety type and could not be accidentally nudged into engagement; instead, they had to be pulled away from a spring-loaded, indented position before being turned to start the lathe. Forward and reverse drive was through a multi-disc clutch with, for stopping, a band brake, this simple device being replaced on later models by a much more effective and automatically applied electromagnetic type that could bring an unloaded spindle from maximum speed to a halt in around two seconds. Spindle speeds varied over the years with a typical, early specification, being twelve in a choice of three ranges: 17 to 750 r.p.m., 23.5 to 1050 r.p.m. and 33.5 to 1500 r.p.m. At extra cost two high-speed set-ups were also available, both requiring a more powerful motor of up to 10 h.p. The catalogue specification of the first gave a range 45 to 2000 r.p.m. while the second, not listed in the charts, ran from 1400 to 4000 r.p.m. and was described in the text as "
Special" and intended for "...the use with ceramic tools or the machining of materials such as copper and plastic." Rather unusually the headstock's front bearing was air cooled by a fan mounted inboard of it on the spindle with filtration taken care of by three units mounted at the left-hand end of the headstock, these being similar to the oiled wire mesh filters found on compressors or, typically, on cheaper two-stroke motorcycle engines as made until the 1960s.
To bring the feed and screwcutting rates into a usable range, the slower of the two high-speed versions had the ratio of the changewheel gearing to the screwcutting and feeds gearbox halved while the "Special" had no screwcutting facility at all - and also lacked the spindle-reverse mechanism. Motors could be flange mounted against the outside left-hand face of the headstock, or foot mounted at the back of the headstock-end bed plinth - drive to the headstock input pulley being by three V-belts. Lubrication was taken care of by a pressure pump that distributed filtered oil through pipes to the required locations - earlier machines being fitted with a centrally positioned manifold above the gears from which the pipes ran; later models lacked the manifold and had revised pipework..

A long-bed Heidenreich & Harbeck 18RO, 21RO and 24RO lathe with a central supporting bed foot

Heidenreich & Harbeck VDF RO24 - the largest in the RO Series

In the bed store;: time for a quick fag and a fiddle with a screwdriver to look busy before that photographer guy arrives

A standard, late-type headstock without the top-mounted oil-distribution manifold and with revised pipework. In the centre can be seen the electromechanical brake and, top left on the lower shaft, the forward and reverse spindle clutch

The "Special" headstock with a fan-cooled front bearing.
At extra cost two high-speed set-ups were also available, both requiring a more powerful motor of up to 10 h.p. The catalogue specification of the first gave a range 45 to 2000 r.p.m. while the second, not listed in the charts, ran from 1400 to 4000 r.p.m. and was described in the text as "
Special" and intended for "...the use with ceramic tools or the machining of materials such as copper and plastic." Rather unusually the headstock's front bearing was air cooled by a fan mounted inboard of it on the spindle. Filtration was taken care of by the two black units seen at the left-hand end of the headstock, these being similar to the oiled wire mesh filters found on compressors or, typically, older two-stroke engines as made until the 1960s.

Touching up the paint finish

A lathe fitted with taper turning incorporating a T-slotted cross slide carrying a two-station rear tool post. Note the very ordinary standard triangular tool clamp - a rather prosaic unit to be found on such a high-class lathe. However, some did incorporate one possibly unique feature, a rectangular plate, able to be swivelled around the mounting stud, against which the clamps levelling screw rested - the idea being, presumably, to prevent marking the top face of the tool slide.

A carriage fitted with the optional power-feed unit that provided rapids for both sliding and surfacing feeds. Automatic disengage stops were fitted to each feed, these being equipped with micrometer screws. All micrometer dials - for the cross and top-slide feeds and the carriage handwheel - were given an anti-glare, satin-chrome finish with the option of dual metric/English engravings. Pivoting from the right-hand face of the apron was a control duplicating one on the headstock and used to electrical start, stop and reverse the spindle. The levers could not be accidentally knocked into engagement - a cause of some serious accidents before the 1950s - the operator needing to first pull them away from spring-loaded, indented positions.
Double-walled, the apron held a supply of oil in its base, this being pumped around the unit and also directed to the bed and cross-slide ways. A sight glass was provided to check the level.

A rather prosaic fitting for such a high-class lathe, the simple triangular-shaped tool clamp assembly fitted as standard did have one unusual (possibly unique) feature: a strip of steel held in place by the toolpost stud formed a resting platform for the clamp's levelling screw - the aim being, presumably, to prevent marking the top surface of the tool slide.


The No. 4 Morse taper spindle of the tailstock was hardened, engraved with ruler divisions, ran in a honed  bore and was locked by a power "split-barrel" clamp. The tailstock was locked to the bed using the action of  lever-turned, cam-shaped cross shaft -  with later models having an additional draw-bolt and clamp plate (as above) to resist the forces encountered during very heavy work). To turn the head of the bolt a special self-hiding spanner was provided.

Static and dynamic stability being tested

Fully equipped: lever-action collet closer, hydraulic copying with template holder, tool back-out attachment and a power driven capstan slide

A large electrical cabinet was provided with plenty of room for additional control elements


A comprehensive Manual is Available for the
VDF 18RO, 21RO and 24RO Lathes in English and German


lathes.co.uk
VDF 18RO, 21RO and 24RO Lathes - Germany

email: tony@lathes.co.uk
Home   Machine Tool Archive   Machine-tools Sale & Wanted
Machine Tool Manuals   Catalogues   Belts   Books   Accessories