email: tony@lathes.co.uk
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Denford Viceroy Variable-speed
Drive Lathes:
Synchro - 280 - 280VS - Enterprise -
Micromatic Inchmetric 280VB

Viceroy Home Page   Viceroy Synchro, 280 & Enterprise Lathes
   
Viceroy Wood Lathes   Viceroy Milling Machines   Viceroy Shaper

T.D.S.-1.L.S., T.D.S.5.G.B., T.D.S.3.M.W. Educator & Type 250

Handbooks and Parts Manuals are available for
most Viceroy Metal Lathes, Viceroy Wood Lathes 
and Viceroy (AEW) Milling Machines and
other Viceroy Publications

In later years the Viceroy range included a number of infinitely variable-speed drive 5.5" x 24" lathes known as the 280, 280VS, Synchro, Enterprise 280/280VS and the "Micromatic", a model fitted with a simple CNC control system. The "Enterprise badge was used on export models whilst the "Synchro" label appears to have been applied almost indiscriminately, the model name having no apparent connection with a particular specification. The 280-Series lathes, with a 0.5" increase in centre height, were a further improvement on the already well-specified and long-established belt-change versions and all were designed to be "easy-to-use" machines with controls conveniently to hand and speed and thread-selection levers that required no releasing pins or clamps to be removed or reset before they could be moved. Two types were made: rear-drive and under-drive; whilst the former could, in theory be supplied for bench mounting they were always fitted to a robust welded steel cabinet with chip tray, splash back, safety interlocks on the covers and the option of built-in coolant equipment. The speed-change system was of the mechanical type with a wide transmission belt running between pairs of balanced cast-iron pulleys one set of which moved further apart whilst, simultaneously,  the other two came closer together - so giving an infinitely variable drive ratio. Whilst most models had their moving pulleys operated manually some Synchro versions were fitted with an electric motor operating through worn-and-wheel gearing with control by either electrical push-buttons or a joystick. Interestingly, the motor used on this drive is wired "Delta" and marked 220v - but fed with 440 volts; this being done, apparently, to give the motor sufficient power to overcome friction in the mechanism controlling the expanding and contracting pulley as they approached the maximum-speed setting. Experiments feeding the motor with 220V have show that, if so supplied, it does not have the power to operate properly.
Because several versions of these lathes were made, and some models appears to be mixtures of different specifications, it is not possible to be categorical about fixtures and fittings (even the factory was confused after few years as to what had been built and when) and the following must be taken as a general guide.
Schools, training departments, prison workshops and similar establishments were good customers for the 280 Synchro models and some were ordered especially well equipped (after all, it's only tax-payers' money) with rear-mounted powered vertical-milling attachments, chrome-plated bedways, T-slotted boring tables, full collets sets, steadies and quick-set tooling commonly being found - by the writer, still unused in the store room 30 years after being put there. Numbers are now about on the second-hand market and, whilst often lightly used, are sometimes damaged due to mishandling of the controls, especially the gearbox. The introduction of these lathes coincided with a raft of burdensome new Health and Safety regulations which workshop administrators and teachers admitted caused them to simply remove all machining from the curriculum and substitute sitting-at-desk theory lessons. As a consequence, as workshops were redeveloped to promote Mickey Mouse engineering and Chinese-made snap-together assembly kits, many unused or merely test-run  examples of these lathes came on the market. Naturally these ex-training machines represented tremendous value for money - though not for the poor taxpayers who funded both their purchase and the salaries and gold-plated pensions of the bureaucrats who then effectively forbade their use.
Continued below:

A splendidly original Viceroy 280 Synchro with the "indented" 12-speed
headstock-mounted speed selector (currently for sale)

Continued:
Although clearly designed with the educational market in mind, the makers did not cut any corners with regard to longevity - the headstock, screwcutting gearbox and apron were are all lubricated from oil sumps, with level windows clearly showing the state of the supply. The headstock, in the form of a tall but very short, open-topped box , carried a No. 4 Morse taper , 1.1-inch bore spindle running in Timken taper roller bearings and fitted, in some cases with plastic (Delron) backgears.
WARNING: the writer has reports of owners using the wrong lubricant on the plastic gears with the result that they swell up, jam and break. In one case, even though the supposedly correct (replacement) oil was supplied it still caused the problem. The 280VS and Synchro were always advertised as having a D1/3" Camlock spindle nose (instead of a thread) and, unlike the threaded nose versions, did not need the strong "hinge-over" spindle lock to remove chucks and faceplates (though some machines were still so fitted).  Slow speeds on the 280VS were provided in two ways: one (with the motor and its variable-speed drive pulleys mounted behind the headstock) was entirely conventional, with a strongly-built backgear assembly engaged through a self-releasing and locking mechanism with a single-lever control. The other (with the motor and drive inside the cabinet base) was unusual: the output shaft from the variable-speed drive carried a small poly-V pulley that drove to a countershaft set above it. From there small and large Poly-V pulleys took the drive to large and small pulleys on the headstock spindle. Sitting between the headstock pulleys was a heavily-built double-ended dog clutch, operated by a lever on the face of the headstock, that allowed either drive to be instantly engaged. Although the latter system was very quiet in operation the use of a belt (rather than gears), meant that the reduction ratio achieved was not as great - nor could it transmit as much torque to tackle really heavy, large-diameter jobs. As far as is known the version with electrical control of the expanding and contracting pulleys was always built with its drive system mounted behind the headstock.
Fitted as standard with a 1500 r.p.m. 3-phase 1.5 h.p. motor spindle speeds ran from 70 to 400 r.p.m. in low range and from 400 to 1600 r.p.m in high.  The pulleys and their-shifting mechanism were very heavily built, to eliminate flex, and give a positive feel to the headstock lever or stand-mounted wheel. Marking accurate speeds on variable-speed systems is always difficult and on the version with a manually-operated headstock lever this was achieved by arranging for it to index through a series of spring-loaded, indented positions, marked with the expected revolutions.  Versions with electrical control (and the Poly-V-drive model that used a stand-mounted handwheel) had their spindle speed displayed on a digital read-out.
Continued below:

Inside the headstock of the unusual Poly-V drive Viceroy 280VS. The serrated ring on the right is part of the pulse generator system for the digital speed read-out
Continued:
Design and location of the electrical-control panels varied widely; in general those with electrically-operated pulleys had a pendant unit fitted above the headstock combined with stand-mounted controls (either in the centre or below the screwcutting gearbox) and generally on etched aluminum panels; others had controls confined just to the stand   Many lathes, especially those purchased for training workshops, were fitted with an unreliable full-length pneumatically-operated foot switch fitted to the front of the stand at floor level.
The screwcutting gearbox drove a 3 mm or 8 t.p.i. leadscrew (with needle-roller thrust bearings) and a separate power shaft, the latter usually (but by no means always) fitted with a most useful automatic disengage to the saddle drive. The gearbox was a comprehensive affair with multi-lever operation, some of which had to be moved with the lathe stationary and other when it was working, allowing an instant change of sliding or surfacing speed. However, before operating the gearbox in this way a careful reading of the maker's operating instructions is essential: it is not safe just to play with the levers and "see what happens". On the metric box 72 pitches were available from 0.2 to 7.0 mm  and on the English box 48 from 4 to 224 t.p.i. Feeds along the bed ranged from 0.03 mm to 2.14 mm or 0.0014" to 0.030" per revolution of the spindle.
Following previous Viceroy practice, the compound slide rest assembly used the same feed screws and nuts - but with the top and cross slide castings squared-off to give a more modern appearance. One point worth mentioning is that some machines have not two but three socket screws to lock the top slide to the cross slide: the missing screw is hidden away at the front of the casting - and not mentioned in the original handbook. Whilst some saddles had plain wings most incorporated "as-cast" T slots in the rear pair that allowed, for example, a travelling steady to be mounted, a toolpost for turning at the extremes of the machine's capacity, jobs to be bolted down for machining by cutting tools in the chuck or coolant pipes clipped in place . 
While most 280 lathes had metric cross and top-slide feed screws a few were produced to inch specification and some carried dual dials, with metric on the inner ring and inch on the outer. The tailstock was particularly strong and, because it carried a No. 3 Morse taper, drill shanks were far less likely to slip and ruin the spindle. Whilst all the handwheels - carriage, compound slide rest and tailstock - were in metal with a durable plastic coating, they tended (unfortunately) to be retained by cheap and nasty spring-dowel pins.
Late-model Viceroy lathes offered a good quality of construction and general specification that, whilst not up to the standard of a Colchester Chipmaster, was available at a considerably lower price and represented excellent value for money. Little-known and underrated they offer terrific value second-hand.
280 Synchro photographs here
If you have one of these lathes and its specifications differs from those described, the writer would be interested to hear from you..
An owner writes:
Now I've owned and used my 280 Synchro for nearly a year, can I offer a few comments to add to your own on the topic?
Generally, I like it a lot, its accurate, relatively quiet, except at the highest speed setting, thanks to a combination of belt primary drive and steel/Delron back gears, and can take  off serious amounts of metal, for a home workshop lathe. Mine is 3 phase run off an elderly inverter, and is the model with 12 speeds controlled by the lever at the top, so I don't have any issues with the 3 phase speed control motor which the VS model is prone too when inverter driven.
Actual spindle speeds are not what Denford claim them to be. The variable speed pulley set up appears to be exactly in accordance with the factory drawings and there is no evidence that they have been 'messed with', but the resulting speeds do not  agree with Denfords stated speeds on the plate on the machine which are 65, 100, 140, 180, 220 and 320 in low range and 380, 500, 700, 900, 1100 and 1600 in high range. Even these differ from the Denford literature which claims 70-260 in low and 400 -1600 in high. Given a back gear ratio of 5.09-1, and taking the lowest speed as 70, which is the lowest I can get, then the lowest speed in high range must be 356, which doesn't correspond with either of the Denford figures. The best I can do, from a starting point of 70, is 70, 90, 120, 145, 175 and 225 in low range and 360, 460, 550, 745, 900 and 1150 in high range. My rev counter flickers a little, so it may be a few revs either side of this, but not enough to account for the difference. Yes its possible to get a higher top speed by adjusting the pulleys, but at the expense of raising the lowest speed correspondingly. Anyway, 70 - 1150 is fine for what I do, and when eventually my old inverter, which doesn't have speed control, gives up the ghost, it will be replaced by a modern one which does, so the whole thing becomes academic.
The saddle has power sliding and cross feed, and the engagement/disengagement is very light even under load. A surprising omission for a machine built around 1980 is that the saddle is not fitted with 'wipers' to keep the dirt out of the slides, and this appears to have been common across the whole Denford range.
Like late model TDS1 lathe, the Synchro is fitted with a safety auto trip on the longitudinal feeds, and this seems to work well, though Denford emphasis that its only a safety device. For accurate working to a shoulder a carriage stop is used. Curiously, according to the Denford Forum for all Viceroy lathes, some TDS 1 machines had an auto knock off on screwcutting as well, but as this worked by means of a rack mechanism opening the half nuts, and taking about 1/2" of travel to do so, this must only have been intended as a safety device, and not as Denford's equivalent of the Ainjest, for rapid thread cutting up to a shoulder. As yet I haven't heard of a 280 with this feature, but as the aprons appear identical, I can see no reason why not.
I like my 280  very much, and consider it to be solid and well built, and I can't understand why they don't seem as popular in the second-hand market place as the equivalent Boxford lathes, let alone the fabled Myford 254 or 280. My Denford, with a full set of chucks, faceplate, catchplate long slotted cross slide and both steadies, from a well known commercial dealer, delivered to my door, was less than 1/4 of the price the Myfords seem to fetch, if and when they ever come on the market..

The drive system of the unusual 280VS model was contained within a very strong (but crudely-finished)  frame constructed from solid rectangular-section steel bolted to the inside back face of the cabinet stand. The shafts were held in self-aligning plumber blocks and, to allow the tension of the final drive belts to be set, the frame could be adjusted vertically by pusher screws at top and bottom.

Connection of the flexible-drive cable to the operating arm that opened and closed the variable-speed pulleys

On the Poly-V drive version of the 280VS the high-low range indicator made no mention of the necessity to engage gears.
The screwcutting gearbox was adorned with instructions and essential warnings

Viceroy Home Page   Viceroy Synchro, 280 & Enterprise Lathes
   
Viceroy Wood Lathes   Viceroy Milling Machines   Viceroy Shaper

T.D.S.-1.L.S., T.D.S.5.G.B., T.D.S.3.M.W. Educator & Type 250

Handbooks and Parts Manuals are available for
most Viceroy Metal Lathes, Viceroy Wood Lathes 
and Viceroy (AEW) Milling Machines and
other Viceroy Publications


Denford Viceroy Variable-speed
Drive Lathes:
Synchro - 280 - 280VS - Enterprise -
Micromatic Inchmetric 280VB

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