Unimat Mk. 2B: although the major components continued unchanged this version it was the first to incorporate a means of aligning the headstock with the bed bars. Upon first assembly the base casting and headstock were jigged and a small vertical slot cut across the junction of their front faces. When the faces were correctly aligned (by using the tailstock method previously outlined) it was possible to insert into the slot a small "setting piece" - a disc washer given by the handbook as being 0.748" in diameter. However, one measured has been discovered to have an OD 0.734", and ID 0.333" and a thickness of 0.1577". Whilst the OD and ID are plain machined the flats were ground). A photographic essay for the Mk. 2B can be found here
Mk. 2B …. The handbook instructions differed from edition to edition, but the following is probably the clearest given: "...two corresponding grooves have been milled in the bed and the headstock housing. If, with the tension screw (No. 4 Fig. 1) slackened, you insert the accompanying setting piece (no. 55) (disc washer 0.748" in diameter) in the milled grove and tighten the tension screw again, the headstock and tailstock will be lined up. The setting piece may be removed again after the headstock has been clamped in position." Removing the setting piece would, of course, have guaranteed its immediate loss.
The motor was the now-familiar larger plain-bearing Dutch unit, with the centre portion painted ether black or in a colour to match the rest of the machine. Several styles of handwheel were used, all turned from steel and plated silver or black. Towards the end of the Mk. 2B production run it is believed that the first of the new (and cheaper to produce) die-cast handwheels with the delightful "wasp-tail" handles was introduced. Some versions of this lathe have been found with two locking screws on the cross slide, one in the normal position nearer the front and the other in line with it further back. Realising that one 6mm screw clamping the casting to the slide bar was entirely adequate, Emco did not persist with this modification. Unimats of this age were also given a more robust carriage assembly with the whole of the casting, including the front and back walls through which the way-bars passed, noticeably thickened.
Colours, as ever, pose a problem and instead of a single, standard finish, examples have been found in crackle-black, a light plain (flat) grey and others in either silver-blue or silver grey - with the latter two in a "hammer-effect" paint.
Unimat Mk. 3: the lathe that introduced the third type of base, longer and with a completely new shape with a convex instead of concave centre section - yet with the headstock support end still rectangular in form and an identical design of headstock-alignment washer. It is likely that only two motors were used on this model: the original Dutch-built brush-type and, towards the end of production, a larger induction . Type. By the late 1950s crackle-black finishes were being phased out and Emco followed fashion by producing the majority of the Mk. 3 lathes in a variety of finishes, amongst which silver-blue appears to have been predominant. The "pea-green", pre-1959 Emco brochure shows just such a machine, with the larger Dutch motor: an example of this type is known to have been manufactured in late 1957, and delivered to its first owner in April, 1958.
The Instruction Book for the Mk. 3 is the more common 3rd Edition, composed and typed (probably) in England as an A4 sheet but reduced to A5 and printed in Salzburg, Austria.
Emco Unimat Model W:
At around this time Emco introduced the Model W, a simplified "Woodworking" version bereft of carriage and feed-screw. The only known data for this version appears in an undated (though circa 1960/64) German-language brochure where the machine appears with a "Model W" script in the top left hand corner of the red nameplate with the European "PAT.ENG" marking. The first version of the W appears to have been based on a mid to late Mk. 3 with die cast handwheels, a U90 motor and an "alignment-slot" headstock. It had the long 12mm Guide Bars (A2Z230010), the long T-bar Tool Rest (DB1201, later DB1202), a wood-drive centre (spur type DB1205) and a single-row ball-bearing rotating centre for the tailstock. (DB1200). The tailstock handwheel was black turned steel with a 'wasp-tail' handle. The same catalogue also shows a unique tool block (DB1320) with two T-slots running front to back and a single clamp screw with a clamp piece. It was sold specifically for use on the 'W' and appears to have been offered in Europe only. It was designed to hold the small triangular tool rest (or other accessories) at the standard cross-slide height. Because it's possible to convert a "W" to the specification of an ordinary metal-turning Unimat (or use the "W" headstock on another machine) it's likely that the model may appear on the used market in a variety on non-factory specifications. Production of the "W" continued into the dies-cast era but, with so few about, only limited numbers can have been sold.
Unimat Mk. 4:
Notable for the introduction of a rounded "step" in front of the headstock through which a simple vertical alignment pin could pass, this was the last version of the Unimat to use a cast-iron base. There was also a slight bevelling of the upper corners of the headstock support - an alteration that would be reflected in the forthcoming die-cast design - and the headstock itself may also have been increased in size slightly but with corners of a tighter radius (measurements are awaited) and its milling post-retaining pin moved to a position parallel to the spindle cartridge.
Motors used on this model included the Dutch-made painted type (the large "round" version), an early example of the very much stronger and reliable U90 (but with more sculptured end caps as shown in the large picture in the 1959 brochure) and the "regular" U90 in a colour to match the lathe. However, it is known that silver-blue finished U90 motors were subsequently sold by American Edelstaal, and Canadian Edelstaal, as replacements for use on later green SL1000s and DB200s and so confusion on this point is a strong possibility.
Early Mk. 4 lathes had blackened steel handwheels with wasp-tail handles, a red nameplate, the Dutch 95-Watt motor and a silver-blue hammer-finish paint. Versions made in the middle years of production can be recognised by the use of die-cast handwheels (still with wasp-tail handles) and a red-silver-red badge. badge. The last Mk. 4 can be identified by a larger, black-finish nameplate carrying the word Unimat (but no model designation) with handwheels changed yet again, this time to a turned-aluminium type with "single-line" knurling around their edges, as also used on the next model to appear, the SL. The motor was a U90 type and the finish either a pale grey-green hammer effect, or plain grey. However, there was a degree of overlap between the machines with even early-production examples found (though only rarely) with the early red nameplate, U90 motors and aluminium handwheels. The Mk. 4 was finished in a hammer-effect, pale grey-green and supplied with the lathe were two accessories that would become very familiar in years to come: a rather light faceplate and drive dog - both in die-cast aluminium. A recent discovery was a Mk. 4 purchased, according to its original owner, in 1960. This had a big round induction motor with matching wrapper paint, a small red name plate mounted low down on the sloping face ff the headstock, green paint and die-cast hand wheels with the wasp-tail handles.
Unimat SL1000/DB200 Die-cast Models
At some point during the early 1960s (evidence points to 1964), the factory went over from an iron base to one formed from a pressure die-casting in a heavy-duty grade of ZAMAK or a similar material. These new models were on sale in England by early 1965, and the USA a little later, in April 1965. However, it is more than likely that stocks of the older cast-iron machines had not been exhausted and the two models may have been available side by side for some time. The change of material enabled the rate of production to be greatly increased and, by eliminating some machining operations (the finish of the castings was equal to a ground surface) costs reduced. The use of dies enabled the appearance of the base to be cleaned up somewhat and allowed an almost full-length, vertical flat face to be used. These first die-cast machines have become known as the "Heavy" Unimat because, a little later, yet another change of material was made to a different grade of ZAMAK resulting in the "Light" version. On the "Heavy" models at the point where the M6 screws retained the bed rails (at both headstock and tailstock) the casting was given two parallel grooves. The "Light" models were painted a hammer-effect green and with minor mechanical alterations only, including rather crude, cast-in degree-graduation marks on the front of the headstock. In America the very last production machines were distributed by LUX (replacing American/Canadien Edelstaal) and can be identified by a large red name plate, U7750 motor and rather horrid plastic handwheels (similar to those on the Unimat 3) - but with clear, white-painted graduations that are preferred by some owners. Unfortunately, this model was not well finished and lacked the delightful detailing of earlier machines: it had, for example, a number of surfaces that lacked accuracy and a headstock spindle sleeve with a turned rather than a ground-finish.
In the 1950s and 1960s very few European countries used the same voltage for their domestic supplies and Emco had to supply a wide range of motors to cover every possibility - new examples of which are still being discovered. As an example of the confusion that reigned an original, unused lathe from 1961 has been found fitted with 125 watt 2800 rpm motor but accompanied by a 3rd edition Operator's Manual stating that a 65 Watt, 4000 rpm unit was fitted. (Machine Serial No. 260031 sold in 1961 for the Dutch market). Apart from the very first examples, American-market machines were fitted with motors of a different design and size to those in Europe (and possibly the rest of the world). The specification plate of a typical US-market DB200 usually read: 95 watts, 3500 RPM, 115 volts, 50/60 cycles, 0.9 A. However, by the mid 1960s the technical literature with USA-market machines was showing two motors: a brush type 16,000 rpm (no-load) and an induction type 3,600 r.p.m. (no-load) unit. Failure of Unimat motors is very common and the causes manifold. However, before fitting a remotely mounted sewing-machine motor as a replacement it is worthwhile dismantling the faulty unit and checking to see if the delta capacitor (for commutator suppression) buried inside the motor casing behind the rear of the armature, is faulty. This unit contains three small capacitors within the single casing and it is not unknown for one to have short circuited to earth internally. If a physically similar replacement capacitor cannot be found an electrically compatible one - in the UK for example a Maplin Electronics Part No. PZB 300 (delta cap, 0.1uF+2×4.7nF 275V) is known to work. If necessary this can be mounted in an external box on the rear of the motor with a new on/off toggle switch on top.
Motors were fitted with either plain bronze or ball bearings with, in general, those for Europe with voltages above 200, using ball races and most American-market U90s with plain bearings - though an exception was the first 40 Watt motor that used ball-races. The plain bearings were lubricated through wicks, and it's important not to take these out and squirt oil in directly, doing so will wreck the motor. If the felts have dried out remove them and soak in thin oil for a couple of days - that usually gets them working again; alternatively, fashion new felts from material easily available from dress-making shops. The ball races are grease lubricated - using oil will wash the grease out and foul up the inside of the motor, again promoting failure. If the motor is stripped, just a trace of grease on the bearings is sufficient - and, whilst it's down, check to see if the bearings are loose in their housings; if they are, secure them with a low-strength grade Loctite. If you are unsure which bearings your motor has, examine the end of the shaft, it's sometimes possible to see the bronze ring of the plain-bearing type.
The early EMCO Maier supplied collet holders were for the E-16 and ES-6 series of collets from Schaublin in Switzerland and were a little shorter than the ER-16 style (introduced in 1972 by Rego-Fix, also of Switzerland, in 1972) ES = Schaublin, ER = Rego-Fix. The E collets have just 6 slots and, as with a collapse range of only a few thousandths of an inch, are intended for use only with the "nominal" size marked on the collet. The ES and ER collets have 8, 12 (or more) slots and a collapse range of about .040". ER collets also have an extraction groove-- the E and ES collets do not. The diameter of the E and ES collets is measured at the largest diameter where the two cones meet which, in the case of E/ES-16 collets, is 16 mm. The ER type are measured at a defined distance below the extraction groove on the 8-degree (16 Degrees included angle).
An ER-16 collet can sometimes be used in an E/EX-16 holder - but never the reverse i.e. an E/ES-16 collet in a ER-16 holder - if this is tried the extractor in the nut will ruin the smaller collet. Although the ER-16 collets will seat in the E/ES holder they will protrude more and the nut may not have enough threads to engage the body safely. Schaublin now makes an ESX-16 collet set that is compliant with the DIN standard.
The E/ES-16 series became obsolete in mid 1980s..
Although the DB200/SL1000 remains a very popular machine on the second-hand market Emco unfortunately no longer supply any parts, accessories, written material or service help.
How long-lived and reliable is a Unimat? In April 2006 the writer met a model engineer who had been given one as a present for his 21st birthday some 40 years previously. Although it had been in regular use, it still retained its first motor (he had been careful not to exceed the time-limited running) and even one drive belt was original. Nothing had broken or worn out and he was entirely delighted with it. Of course, collectors have moved into the market and very early black-finish machines - and most of the accessories from any year - are very sought after and command high prices.