Manufactured by the IMAMI Machine Tool Company in Cologno M. (Milano) Italy, the "semi-automatic" Aristos IMAMI lathes plain-turning precision lathes were offered in several different forms. The origin of this simple but effective "bench precision" type (as it's often known) goes back to Stark in the USA in 1862 and their "Toolmaker" lathe. This was a machine intended for one-off precision jobs by a skilled turner and always set up with a compound slide and tailstock both controlled by screws and often a simple draw tube for holding collets in the headstock spindle. The same lathe could then be adapted to perform as a "Second-operation" or "Finishing" machine, the transformation involving the use of lever-feed controls to the slide rest, tailstock and collet closer. Set up like this, the lathe was intended to be part of a production process where simple parts could be either further modified or finished. The final and most complex arrangement was the "Production" or "Capstan" type - this being fitted with a bed-mounted 6-station indexing capstan unit and, according to the particular job being tackled, either lever or screw-operated slide rests and a quick-action collet closer. By the simple means of changing the fittings mounted on the bed, any version (or combinations of versions) could be assembled in a matter of minutes and pressed into service with a minimum loss of time.
As a more modern version of the classic "bench precision", the 800 kg Ariston IMAMI concentrated on second-operation and capstan types - all versions being constructed with the bed and stand formed as one very heavy and rigid unit aged and stabilised cast-iron. The centre height was 5.5 inches and the spindle, manufactured from high-tensile steel, could pass a bar 1.75 inches in diameter and accepted Brown & Sharpe collets Type N22 collets with a maximum bore of 1.25 inches. The hardened and ground collet holder was detachable and could be replaced by a self-centring 3-jaw chuck with a through capacity of 1.75 inches. The spindle bearings - of an unknown type - were lubricated (presumably from wick feeds) from individual oil sumps set beneath them.
Versions of the lathe offered included the IMAMI A-16 with sixteen spindle speeds of 55, 75, 115, 125, 150, 175, 250, 345, 450, 600, 920, 1000, 1200, 1400, 2000 and 2780 r.p.m., a turret slide with either hand drive or two rates of power feed (0.003" and 0.006" per minute) and a screw-feed cross slide. The N-16 was identical, but less the power-feed turret; the TRP-16 was built as a second-operation model without the turret but with a choice of lever or screw-feed slides; a cheaper option was the N-8, a model equipped as the A-16 with 8 spindle speeds of 380, 535, 760, 920, 1070, 1230, 1840 and 2460 r.p.m. and the speed-change gearbox replaced by a V-belt countershaft; this lathe could also be equipped, as a second-operation type without the turret slide when it became known as the Model TRP-8.
Drive came from a piston-pump-lubricated speed-change gearbox mounted inside a ventilated compartment in the left-hand end of the stand. It was connected, by a pair of V-belts, to a 2-speed motor of 3 and 3.6 h.p. bolted to a hinged plate that allowed the belt tension to be adjusted by a handy knob. Control of the spindle was by a twin, multi-disc clutch that acted as a brake, the motor (to speed up production) being left running as the spindle stopped. The stand also accommodated the standard-fit 0.15 h.p. coolant motor, its pump and supply tank.
With a stroke of up to 6.5 inches, the capstan head slid on adjustable V-ways and took tools with a 1-inch shank. Six index positions were available, these being adjustable against lugs that were in case-hardened steel, heat-treated and ground. At the return from a working stroke, the head was automatically indexed to the next position, the usual six-position drum carrying screw adjustable stops being provided.
Fitted as standard with a screw-operated cut-off (forming) slide with front and rear toolposts, this could also be had with lever control and also supplied, in either case, with a lever-operated swivelling top slide. It appears that - unlike for example the Swiss Mikron precision lathe with its very wide range of slide types - a simple compound screw-fed slide for toolmaking work was not available. By way of contrast, a standard screw or lever-feed set-over tailstock was listed so, presumably, the makers did intend the lathe to be used for jobs held between centres.
Various accessories were available including, mounted on the headstock nose, a vertical tool slide for jobs such as cutting-off, cutting in and knurling; a complete thread-chasing attachment; a bar-feed unit, and a pneumatically-operated collet chuck.
Other examples of might be termed "late-type, professional-class compact capstan lathes" (as distinct from the smallest Ward and Herbert models) include the Italian Ceriotti, the British Accuratool, Britan, Exacta, the Spanish Elgo, versions of the German Weiler 260 and the Dutch Emwee..