email: tony@lathes.co.uk
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ALPIN Lathes - Italy


Alpin lathes (also written as "Al.Pin") were manufactured by OMAP (Office Meccaniche Alberto Pinchiroli) with an address listed as: San Giorgio Su Legano via. Magenta, 25 Italy.  Details of just three of the more popular machines from the 1950s are available: the Al.Pin 200, Al.Pin 180 and Al.Pin 160 described by their maker as tornio monopuleggia, that is, in American terminology, a "single-pulley engine" lathe. Although all were cosmetically similar - and shared some details of their specification - each was a model in its own right and correctly engineered for its task with non of the heavier castings shared between them.
The Al.Pin 200 was of 200 mm centre height and could be ordered with a either capacity of 1000, 1500 or 2000 mm between centres. The 320 mm wide V-way bed was of deep rectangular section, with almost no cut-away along the bottom edge, made of heat-treated (but not hardened) cast iron and with a ground finish. A gap was provided as standard and allowed work up to 600 mm in diameter and a maximum of 150 mm thick to be carried on the faceplate. The bed was supported on separate, very heavy cast-iron plinths under headstock and tailstock with a slide-out chip tray between them.
For its era the headstock assembly had pleasing, clean lines and held a heat-treated and ground 45 mm bore spindle running on a bronze bush at the front, an adjustable bronze bearing in the centre and a ball race at the rear. The spindle nose, carrying an American Long-nose taper in an L0 size, was, like its bore, rather small for the lathe's size and weight: a larger-diameter spindle with an L1 nose (the next size up) would have been more appropriate as was fitted, for example, to the Colchester Mascot, a contemporary lathe of similar capacity. It is likely, though not confirmed, that early versions of the lathe would have had a screwed spindle nose. The headstock gears were all in heat-treated alloy steel and ran on ball races - the whole assembly positively lubricated by a pumped oil supply. However, the spindle drive was not solely in the headstock, instead the 4-h.p. electric motor was fitted in the base of the headstock-end plinth and drove, by 3 V-belts and a double multi-plate clutch, to a speed-change gearbox with oil-bath lubrication and hardened gears running on ball-bearing supported shafts. One of the clutches was used for forwards rotation and the other reverse. From the gearbox the drive to the spindle gearing was by 4 V-belts - this combination of drives resulting in a generous 16 speeds that spanned a very useful 25 to 1500 rpm. Electrical start, stop and reverse was under the control of a "third shaft" control rod parallel to and below the power-feeds drive shaft. This could be operated by a handle next to the screwcutting gearbox or one pivoting from the right-hand wall of the apron where, because it moved with the carriage, was always within easy reach an operator in his normal working position.
Operated by just a row of four levers on its front face, the screwcutting and feeds gearbox lacked the usual sliding tumbler lever working across an open slot and so was able to be fully enclosed and to run in an oil bath free from the ingress of swarf and dirt. Strangely, even for markets that were fully metric, the 35 mm diameter leadscrew was of 4 t.p.i (
4 filetti per pollice) with the screwcutting gearbox able to generate 24 English, 19 metric and 13 module pitches - with each set being obtained by changing just one or two of the drive-train gears. With the standard changewheels in place 12 longitudinal feeds from 0.075 to 0.7 mm and 12 cross feeds from 0.09 to 0.35 mm were available - all per one revolution of the spindle. The leadscrew drive could be uncoupled from the gearbox and so was required to run only when cutting threads.
Deep and strongly built the apron was doubled walled with all shafts supported at both ends and fitted with a lever-operated clutch to both select and engage the power sliding and surfacing motions.
Heavily constructed, the No. 3 Morse taper tailstock was designed with a casting that allowed a close approach to the headstock - yet with enough room for the carriage to work on very short between-centres' jobs. Locked to the bed by a captive lever working through an eccentric cross shaft it did look rather old fashioned in comparison with the rest of the lathe.
The Al.Pin 200 was delivered complete with a motor and switchgear, spanners, a 0.25 h.p. coolant pump with distribution pipes and tank, a 350 mm diameter combined faceplate and light-duty 4-jaw chuck with hardened jaws (a popular and inexpensive-to-supply fitting at the time), a drive plate, a 250mm diameter backplate intended for the mounting of a 3-jaw chuck, a fixed steady, a  travelling steady, a headstock spindle adaptor to reduce the bore from a No. 5 Morse to a No. 4 and 2 ordinary hard centres..


Al.Pin 200 mm  x 1000, 1500 or 2000 mm between centres.

Above and below: Alpin Models 160 and 180 - virtually identical apart from their centre height.

Although very close to each other in specification (and difficult to tell apart at a glance) Al.Pin 180 and 160 lathes were separate models in their own right with not just different centre heights (180 mm and 160 mm respectively) but with beds of different width (240 and 280 mm), removable gaps of different length (180 and 200 mm) and different electric motors (2.5 and 3 hp). In other respects however they were similar, indeed, very like the Al.Pin 200 described above with an identical drive system split between plinth-mounted motor and gearbox in combination with separate gearing inside the headstock.
Each shared the same headstock internals - hardened gears with a positive lubrication system - with the 33 mm bore spindle carrying a rather undersized L00 American long-taper nose (an L0 would have been a better choice for both machines) running in a bronze bearing at the front and a roller race at the rear. 16 spindle speeds were available from 26 to 1500 rpm with the electrical start, stop and reverse was under the control of a "third shaft" control rod exactly as on the Al.Pin 200.
Of identical mechanical layout to those on the Al.Pin 200, the screwcutting and power-feed arrangements retained the same 4 t.p.i. Leadscrew for all markets - although it was of a smaller (28 mm) diameter. The box produced the same set of 24 English, 19 metric and 13 module but, reflecting the smaller jobs they were designed to tackle, the two lathes were given different finer rates of power sliding and surfacing feeds: 0.05 to 0.5 mm and 0.025 to 0.25 mm respectively per single revolution of the spindle. Control was by foure levers, the lack of a sliding tumbler meaning the box could be sealed against dirt and swarf and lubricated from a sump by splash.
Of conventional design the apron incorporated a lever-operated clutch that both selected and engaged the power sliding and surfacing feeds.
Like that on the Al.Pin 200 the tailstock barrel was swept forwards to allow its No. 3 Morse taper tailstock to centre to almost meet that in the headstock yet leave enough space for the carriage to work on very short between-centres' jobs.
The Al.Pin 160 weighed 830 Kg and the Al.Pin 180 approximately 920 Kg. Both lathes were delivered with the same equipment as the Al.Pin 200 but with a smaller 280 mm diameter combined faceplate and light-duty 4-jaw chuck with hardened jaws and a 180 mm diameter backplate intended for a 3-jaw chuck. The spindle adapter was a 5 Morse to 3 Morse and two ordinary hard centres were also supplied as part of the standard accessories


email: tony@lathes.co.uk
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ALPIN Lathes - Italy
Alpin 160 & Alpin 180