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Running in large taper-roller bearings, the 20 mm bore, No. 3 Morse taper spindle was fitted with a 2-step V-pulley overhung on its left-hand end and driven by a soft-start 1/3 h.p. variable-speed drive DC motor. Using a combination of the rotary speed control knob and the two-step belt drive gave a slow range from 1 to 600 r.p.m. and high from 1 to 3200 r.p.m. While torque at the lower end of even the low-speed direct drive was lacking, once in backgear the machine was capable (reports an owner) of drilling with ease a 20 mm hole through a 30 mm thick steel block. At the highest speed, he reported that it was possible to fit and use successfully a grinding wheel with a minimum diameter of 100 mm and, when the 450  diameter faceplate was used at that speed it spun with absolute smoothness - the radial slots making more wind noise than the motor or drive. Similarly, with the highest speeds engaged and using a rotary table, several 50 mm hardwood ball handles were tuned with a very impressive surface finish and it was possible to turn 10 mm long brass pins to a diameter of 0.6 mm. He also commented that for most light to medium machining or drilling, the "steady legs" reaching from base to headstock (as shown in the brochure) were not required, but clamping one near the chuck did steady things, allowed a finer turned finish to be achieved and heavier milling and fly-cutting tasks undertaken (interestingly, the legs double in duty a right-angle clamping plate on the top-slide when drilling horizontally).
Further interesting observations received included: "Mounted on a turntable, the heavily built (40 kg) cross and top-slide unit could, when unlocked, be spun around with one finger and had easy-to-set tapered gib strips on both slides - the final adjustment giving a smooth, even feel to the controls. Not shown in the parts drawings was a knurled-end taper pin that passed through the base of the top-slide at its rear, this enabling the turntable to set the lower slide square to the bed; the pin was easily removed for more adventurous positioning.  Another tapered pin was used to set the tailstock to precise horizontal before clinching the single securing bolt - though this feature was absent on the extended tailstock model. The 360-degree rotation of both slides enabled the lower slide to be angled or aligned with the bed, and opened up some interesting possibilities with the top slide able to become, in effect,  the cross-slide - one especially tricky shaping job on an antique boat winch used both slides at differing angles to both the bed and each other. Reversing the roles of each slide also allowed longer support and easier clamping for sheet or plate stock along the edge of the top slide for sawing or fly-cutting, rather than at the end. The lower slide then become the feed with the rotational function still available for alignment of the workpiece. Of course, the headstock became the third axis, being lowered slowly into the work for sawing thicker jobs that had to be taken in several passes.
Built into the turntable was worm-and-wheel gearing to rotate the top-slide, an eccentric barrel providing a way of removing all backlash. While it was possible to use this feature as a dividing head, it was better suited to taper turning, ball turning, setting angles for milling, chain drilling circles and adjusting items clamped on the table into perfect alignment for fly-cutting or metal sawing.
Another turntable and rotary control was built into the headstock column connection and allowed both precise angular settings to be made and the headstock rotated into a position for vertical milling and drilling. A long Morse taper No. 3 test bar allows a rapid set-up for ascertaining true horizontal or vertical alignment of the headstock.
The writers machine was earlier than those depicted in the brochure and differed in having triangular slots in the top-slide and an earlier design of tailstock - the later  "extended tailstock" version giving an increase in the capacity between centres. Other minor improvements incorporated over the years included lead-screw adjusters, handles and dowel pins in the column bases.
The floor of the sturdy cabinet stand was drilled to bolt down the cast-iron baseplate, and all parts could be secured within - the design allowing the Armed services to pack down the unit, forklift it onto a Hercules and rapidly set up again for repair work in the field.
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Factory visit.
In 2002, the writer and his wife visited the premises of the Precision Grinding Company, seeking spare parts to future proof the machine. We were treated most courteously by the manager, Mr E.Erns, the designer's son, and the draughtsman for the Unimac drawings. Mr Erns ruefully stated that the company no longer had a complete, working Unimac and we were sent off to search the dim rear part of the factory - with a warning to watch for snakes! Rows of Dexion shelves help numerous spares, several of which were secured at minimal cost. We were also shown a longer-bed, intended for production, that would have employed the same major components as the standard model.  While the grinding part of the business was still functioning, with a handful of workers, Unimac production had long since ceased, a victim of the tsunami of nameless Asian product that had gutted so many makers of small machines tools.
After a life-time working with a wide range of production and industrial machinery, and owning several lathes and milling machines, the writer can state that the Unimac is by far the most "viable", and ingenious machine he has ever encountered. His example is in almost daily use, and tackles every machining task with ease.
It take some lateral thinking to appreciate the scope of this machine, not just an engineering degree. The writer's wife had no trouble quickly assessing the potential on her first sighting, such that she insisted it be purchased as a versatile addition to our workshop.
Given the staggering array of machining jobs this machine has successfully completed, it has been incredibly useful, endlessly interesting, and a delight to own..