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CVA Precision Lathes

CVA Miniature Precision & Capstan Lathes

A Copy of the Maker's Instruction and Parts Book is available as well
as the special high-quality flat belts for the main and auxiliary drives

Manufacturers of Automatic gear cutters, gear hobbers, automatic lathes, dieing presses and milling and die-sinking machines, CVA made only a limited range of conventional lathes: their first was the little round-bed "CAV Wade", designed for the lower end of the amateur market (a machine that was to remain in production until the late 1930s) a number of small plain-turning precision bench and capstan types and a much larger toolroom model closely modelled on the fabulous American Monarch 10EE  (the latter introduced during the late 1930s and still in production today (2010). The equally beautiful CVA version was made in England from the 1940s until the late 1980s - when they were still available from the then manufacturers formerly E.H.Cole and then possibly as H. Cole & Sons of Curtis Road, Dorking, Surrey for 28,700, plus another 2960 for the taper turning unit.
C.V.A. began in 1917 as C. A. Vandervell & Co Ltd. (C.A.V.) to produce war materiel including munitions. As the Company grew (and doubtless taking on other work) a foundry was added in January 1926 and then, in December 1929, plans were announced expand this and add a heat-treatment shop - the facility opening in early 1930. With a further name change in 1934 to
C.V.A. Jigs, Moulds & Tools Ltd. the firm flourished throughout WW2 and, by its end, was well positioned to re-enter the civilian market. It's heyday came during the 1950s when, in 1953, for example, it was so busy it had no fewer than 73 apprentices. A further and final change of name to F.M.T. saw the firm wind down during the 1990s.
Always an expensive machine, from 1948 to 1953 the toolroom CVA sold (depending upon equipment) for between 700 and 1000, a sum that would, at the time, have bought a very good house in the better parts of any UK city. For its final form, Coles proposed the fitting of a CNC control system;  however, only very limited numbers can have been made and the one installed in a Trowbridge college during the 1980s was reported to the writer as not being up to contemporary standards and lacking in power.
Constructed as an uncompromisingly accurate and finely detailed machine tool the original CVA occupied about the same floor space as a Colchester Student but, with its cast-steel stand, weighed over three times as much. So confident were CVA in the rigidity of the machine that the stand's three floor-mounting points (two pads at the headstock end and one at the tailstock) had no provision to mount  anti-vibration pads - however, if a machine was to be (unwisely) installed on other than a level floor, the makers advised that it be packed up with metal shims.
To insulate the headstock spindle from vibrations associated with gear drive, the electric motor, spindle-speed gearbox and clutch unit were remotely mounted inside the base of the machine - and drove the headstock through multiple V belts on early versions and, for greater smoothness, a flat belt on later models. Three different ranges of twelve spindle speeds were offered: Range A gave 25 to 1645 r.p.m, Range B 29 to 2220 r.p.m and Range C (at extra cost) 40 to 3100 r.p.m.
When sliding and surfacing feeds were selected (by individually clutched levers on the apron face  - another beautiful touch) the drive, as on some Lorch and Schaublin lathes, was transmitted not through the screwcutting gears but by belt to a separate gearbox. This allowed not only much finer feeds to be provided, especially at high spindle speeds but also prevented the transmission of "gear marks" to the drive - as well as saving wear and tear on the screwcutting mechanism.
Taper turning, of a unique design, incorporating adjustable ball bearings to the slides and the ability to set tapers to within one minute of arc, was fitted as standard - and, because it incorporated a telescopic screw, it was possible to use the cross slide with the taper turning engaged.
A "post-production" CVA appears to have been made in very limited numbers, possibly during the early 1980s. These lathes featured a massive 10 hp DC motor, with a complicated control system, driving through a expanding and contracting pulley system, the movements of which were chain driven from a 0.5 hp electric motor. The top speed was 3000 rpm.
Because of its standard-fit clutch the standard CVA is one large lathe which works well when converted to single-phase electrics - and numbers are now finding a second life employed in the private workshops of those model and experimental engineers who appreciate being able to use a precision lathe originally constructed without regard to cost.
Over the years small various changes were made to the specification, and also to the maker's Model designations. However, these appear to have been few in number and (apart from the restyling to a square-look appearance) and rather minor. For example, in the Series II brochure one option was a set of screwcutting changewheels to generate 19 t.p.i. However, the Series III manual (maker's code PD1143) listed the lathe as having 19 t.p.i on the standard feed-selector dial - it would appear that when the decision was made to change the rounded Series I styling to the angular (as we see on the series III) the plan would have been to include 19 t.p.i. in the gearbox  For whatever reason this did not happen immediately so, the new styling was designated as the series II (with no change to the gearbox) and a short time later the new gearbox (and possibly the change to flat-drive belt) was introduced as the Series III. Even so, to great confusion, some Series 3 machines have been found without the 19 t.p.i. pi feed - possibly caused by a glitch in production process, or even a mistake by the maker.
For a fuller explanation of how the CVA was originally conceived and developed see the American monarch 10EE section of the archive
Continued below

CVA No. 1 Toolroom Lathe 6.25" x 22" - later versions, the No. 1A (from 1951) and No. 1A Series 3 (from approximately 1952) were comprehensively restyled (though mechanically very similar) with a straighter edge to the front of the stand and changes to the apron, cross and top slide units; the headstock end was also "squared off". The result (below) was a lathe which, even today, looks remarkably modern.

CVA lathes by Cole: an interesting account (2014) by a former employee, Justin Hill:

This morning I was chatting to a retired chap who mentioned machine tools and it reminded me that in my youth I worked for a couple of years at Cole in Dorking (between 1979 and 1981).  In our conversation I couldn't remember the name of the lathes they were so proud of so when i got back to my desk I started Googling and found your site.
I can't tell you anything very helpful about the CVA lathe I'm afraid - my skills are in IT rather than engineering.  My job there was wiring the electrics on the lathes and various milling and drilling machines.  As well as 'classic' set-ups I was involved in fitting electronic speed control and also a few Olivetti CNC systems.
The workforce seemed, to my inexperienced eyes, to be highly skilled, and dedicated to absolute precision.  They built new lathes and also re-built older ones (more re-building than new as I recall).  However, even at my young age I could see that the management of the business was poor and the place was chaotically run.  My workplace was on the 1st floor of the building and there was a gigantic hoist for moving the tools in and out of the building.  The ground floor was a general engineering operation, full of machine tools, noise and filth.  The back of the Curtis Road site was full of lathe castings 'seasoning'.  They would often buy old CVA lathes and then re-build them as new.
Each of the two floors was run independently I believe, each by a Cole brother - the ground floor engineering shop being "E. F. Cole".  I may be remembering this correctly, but I think the workers used to mutter darkly about a 'Cole Senior' who "knew what he was doing" and the place having "gone to seed" when the two sons took over.   Even I, a newcomer, could see that the business was failing.
Having no proper engineering background I can't tell you anything about the quality of the machines they produced but I remember being astonished at the hours or days blokes would spend 'blueing' lathe beds and scraping microscopic imperfections out.  Their standards seemed ridiculously high to me, and management were often at odds with their work because they wanted to minimise the time and money spent on each machine.
There was also one chap who had a large huge spray booth and spent all his time filling, sanding and spraying the castings (in a particular blue) until they looked perfect.  Then he'd just sit in an old chair smoking roll-ups and threatening anyone who came near enough to risk 'raising the dust'.  He was also a perfectionist in his way.
I don't know much about where the lathes went I'm afraid.  It's a long time ago and it wasn't part of my job anyway. However, I did have to make a number of 'service calls' and visited one of the BL factories around Coventry once or twice - and also somewhere at Heathrow where they were maintaining Concorde parts (I saw a wheel strut assembly there).   I was told there was a CVA lathe at Woolwich Arsenal (?), in a specially-built blast-proof area where it was used to machine explosives and operated by remote control.
For most of my time at Cole's I wasn't even employed by them.  I actually worked for an on-site subcontractor called Mike (?) Pollard.  I found out the hard way that this system of subcontractors saved Cole from having to pay redundancy when I got my marching orders.  Pollard was a genuine eccentric who lived somewhere in Westcott with his long-suffering German wife, drove a 1950's ex-Post Office van and was building a nuclear fall-out shelter in his back garden.
I was often allowed to take work home, this being in the form of a large metal panel that I would populate with up to several dozen relays and then wire up according to huge wiring diagrams I'd Sellotape around my bedroom walls.  Then I'd take the finished article back to work and 'plumb it in' to some turret drill, milling machine or lathe.  The part I really hated was drilling all the holes in the castings for my cables and fitting the 'Anaconda' flexible trunking.  The part I enjoyed was connecting everything up and testing it.  Only a fraction of the tools I worked on had the Olivetti CNC stuff, but they were always the most interesting to work on.  Whenever anything went wrong, the first clue that things were amiss was the controller language reverting to its native Italian language.
Continued below

CVA Mk 1A  Series 3 circa 1956 with electrical-switch control bar running the full length of the bed.

A readers experience of a Coles version of the CVA with variable-speed drive:
Thank you for your amazing and informative website!!
I run both the earlier CVA toolroom lathe, with the normal motor and gearbox, and the late Coles one with the Variable-speed drive.  In fact I think both might be Coles lathes, the standard one is 1986 (small  Royal Air Force Research and Development sticker inside the bed).  I can't find a date on the variable-speed one.
Both are excellent lathes.  I am by no means an expert machinist, but I am ok, as I have winged it before now in jobs when I said I was a skilled milling machinist (I am not, I just go slowly and avoid mistakes....)
In my experience, the variable-speed one has some advantages in use, and some disadvantages.  Starting with the advantages: the variable-speed drive is amazing.  The lathe is in an unheated and very damp shed for several years, and it all still works fine.  There are two ranges, low and high, which you select with a button on the front of the lathe, and you just twiddle the knob to get any speed from virtually zero to 3000 r.p.m. - and it is very powerful at all speeds.   It has a one size larger Morse taper in the tailstock, simple I know, but it is much, much better, and you can use big drills to save time.
It has dual dials on the movement handles; these have epicyclic gearboxes in them (not on the tailstock) so the metric graduation rings spin at a different speed to the imperial when you turn the handles, so the movements are exact for both.  This is also great, however it does make the handle on the cross slide stiffer to turn, so if you are setting up a job, or changing the tool, and need to move the cross slide some distance, you can't just spin the handle to wind it in or out, you have to grab it properly and turn it in half turns.  This is somewhat laborious and a bit of a pain.
The handle that slides the apron along the bed is also graduated on the variable speed lathe.  It is not a vernier, just a graduated ring, but you can see how far you are moving the apron within about half a mm, which is useful.
From any speed, the spindle brake stops the chuck instantly - and then releases automatically after a couple of seconds.  The chuck remains very stiff to turn though as it's connected to the large DC motor and there is no neutral position.  I have never had to do it but, if for example you were clocking something up in a 4-jaw independent chuck, it would make it very difficult to do properly.  I think you would have to put the chuck key into the chuck and lever it round -  which is not ideal.
Both lathes are amazing to use for a layman.  I had a Colchester Student before, which is all I can compare them with, and it was very worn as well, so not really a very valid comparison.  Both the CVAs I have are late ones, with little wear, and I can probably take a cut ten times larger than with the Colchester, and still have accuracy.  I machine all sorts of bits of scrap as raw material, some of which was literally impossible on the Colchester, it just wouldn't touch it..

CVA Mk 1A compound slide detail - with the optional micrometer bed stop fitted on the left-hand edge of the saddle. The spindle speed-selector wheel is at the bottom left, with the selected speed showing in a window. The clutch lever is on the front face of the headstock, just below the headstock front bearing oil-level window.

A particularly well-preserved CVA Mk. 1A

Although this is a CVA Model 1A, all versions were laid out in exactly the same way. With the cast-aluminium end covers removed the separate motor and gearbox unit can be seen in the base of the stand. The jockey pulley, on the left-hand side of the machine level with the top of the stand, tensioned the main drive belt. The flat belt, driven from the end of the main spindle, provided auxiliary super-fine feeds for power sliding and surfacing.

Section through the headstock.

The black handle at the top right is the spindle clutch lever; the small upper knob selects left and right-hand feeds to the carriage; the large circular plate is engraved with a screwcutting charts with the central push-pull-twist lever to select threads and feeds - whilst the spindle speeds are selected by the large dial at the bottom right of the picture.

Large, clear micrometer dial

The two horizontal levers engage the spring-loaded clutches for power sliding and surfacing.
The apron is particularly rugged and beautifully constructed and contains within its base an oil pump (and oil sump) from which lubricant is distributed to the bed, cross slide and leadscrew clasp nuts. Over many years the springs and balls within the oil pump valves can  become tired and "sticky", and the gauze filters blocked. Happily, it is a simple job to remove the sump and clean everything out - fitting new springs and balls if necessary.
If you want to remove the apron completely, first locate the plate on the saddle which covers access to the brass oil pipe feeding the carriage. Remove the pipe connection and then, having released six of the eight Allen screws securing it, find some help in holding it (or make other arrangements) before releasing the final  two screws.

Taper-turning unit with micrometer adjustment of the angle setting.

Late-model CVA lathe with an early type of electronic speed control as manufactured by Cole brothers in
If any reader has a similar example, or any sales literature about the machine, I would be very interested to hear from you.

CVA Miniature Precision & Capstan Lathes

A Copy of the Maker's Instruction and Parts Book is available as well
as the special high-quality flat belts for the main and auxiliary drives

CVA Precision Lathes
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