Manufactured during the 1950s and 1960s by S.I.M.A. (Societ?Industria Macchine Accessori) at Vignale, in Italy, the Rossi V0 turret miller was a versatile, well-made machine built along traditional Bridgeport Series 1 lines - though, unlike the usual clones of that machine sold by so many other makers, the Rossi was entirely novel.
Constructed as a one-piece casting, the main column and foot were internally ribbed with the base doubling as a coolant tank with the fluid lifted by a 0.15 h.p. motor. Sitting on top of a boss able to be swivelled through 360? the ram was of prismatic shape, well ribbed internally, held in V-shaped guide ways and moved through its 15 inches of travel by a large handwheel on its right-hand side. Two rams were available: the first had a plain vertical head mounting flange while the second incorporated a knuckle joint at the end that allowed the head to be nodded through 45?above and below horizontal - the movement being under the control of a handle working through worm-and-wheel gearing. Only the standard ram was machined on its other end to mount the optional slotting head.
Just a single vertical head was offered, though the buyer was given a choice of two speed ranges: Standard or Fast. Both were driven by a (short-height) 1.5 h.p. motor and each had either 8 speeds by direct belt drive - or 16 with the inclusion (at extra cost) of reduction gearing. The Standard range of eight speeds gave: 80, 135, 220, 360, 660, 1100,1800 and 2860 r.p.m. and the faster set: 100, 167, 219, 495, 790, 1350, 2300 and 4000 r.p.m. With 16 speeds the Standard range became: 40, 67, 80, 110, 135, 180, 220, 330, 360, 550, 660, 900, 1100, 1430, 1800 and 2860 r.p.m. and the faster: 65, 135, 145, 220, 250, 300, 400, 500, 520, 1100, 1200, 1740, 2000, 2400, 3240 and 4000 r.p.m. Having such a high top speed allowed the makers to suggest that the machine could be used for vertical grinding, and to assist with this offered a special table-surround guard to help contain the grinding dust residue.
Running in high-precision roller races, the nickel-chrome spindle with its ISA 30 nose was hardened, tempered, ground all over and contained within a quill whose outer walls were hard-chrome plated - the better to slid in its honed bore. Spindle travel was under the control of a fine-feed handwheel, a quick-action lever for drilling work or by power, with three rates of feed available: 0.0016", 0.0031" and 0.0059" per revolution with a useful brake incorporated to save time when stopping from higher revolutions.
One unusual feature of the Rossi was its ability to undertake horizontal milling, achieved by placing a housing, containing a horizontal spindle (running on taper roller bearings), between the top of the column and the ram's swivel housing. The head was swung to the rear, coupled to the spindle with a pair of helical gears (arranged to give a 50% reduction in speed) and the ram brought forwards to allow a drop bracket to be fitted to support the end of a cutter-holding arbor. With the horizontal set-up in place, if the head was swung to the side the effect was that of the machine having a swing table, enabling it to perform, with the help of a universal dividing attachment, helical milling operations.
With a working surface of 47.25" x 9.125" (plus a surrounding coolant drain channel) the table had a longitudinal travel of 27.5", in traverse of 9.8" and vertically of 19.7". Fitted with three T-slots set 3.05" apart (and a fourth along the front face to hold feed knock-off blocks, comparators, micrometer heads, and other measuring equipment), the table could, at extra cost, be fitted with 6 rates of power feed together with rapids on all three axes. Sensibly, the vertical feed rates were set at half those for along and across. The feeds' gearbox was mounted beneath the saddle and, driven by a 1-h.p. 3-phase motor, held hardened, ground and lapped gears running in an oil bath. There was no need for a shaft with universal joints and splined shafts (or any exposed, moving parts), the entire mechanism was in constant mesh and neatly enclosed. Usefully large handwheels were fitted to all axes of travel, with two on the table - one handle being an annoying. cost-cutting features with many makers. Even the micrometer dials were of a good size - 3.937" in diameter - and finished in a pleasing, non-reflective satin-chrome. All feed screws were made from high-tensile steel and ran through double bronze nuts that could be adjusted to eliminate backlash. To prevent the table overrunning the limits of its travel, electric limit switches were used on each axis.
As expected, the maker's offered a range of accessories including a useful Model TSA slotting head. Weighing 242 lbs, this mounted a 0.5 h.p. motor and had a maximum stroke of a little over 3.5 inches. Five stroke rates were provided of 24, 56, 85, 126 and 190 per minute. Other items included the contemporary means of accurately measuring table and ram travels - a set of precision length rods and dial-test holders - plain and swivel-base machine vices and a universal dividing attachment.
If any reader has a Rossi milling machine, or other machine tool by the Company, the writer would be interested to hear from you..