Built in Italy by Carlo Magnoni in Oggiono (north of Milan at the foot of lake Annone), Arno and Nomo milling machines were handled in the UK from the late 1940s onwards by a sole selling agent, Pidgen Bros. Ltd. of Helmet Row, Old Street in the Clarkenwell district of London, E.C.1. However, other sales literature lists the makers as Nomo S.p.A. of Oggiono, Como from which factory some machines were dual badged as "Arno" and "Nomo" - or just the latter. Other catalogues have been found with the manufacturers listed as "Valdagno" S.p.A of Valdagno, Vicenza.
From the 1950a until the 1970s the Company's range of models included Universal miller Types: No. 0; No. 1A; No. 1AR; No. 1N ; No. 2; No. 2R; No. 2N; No. 3; No. 3N; No. 4N; the Nomo HD in sizes 0HD, 1HD, 2HD, 3HD and 4HD and the No. 5 a "Milling and Boring machine". Vertical millers were also offered in a variety of sizes and included:  No. 1 Vertical; No. 1V; No. 1VR Vertical; 2N vertical; 3N vertical; 4N vertical  and the Nomo Vertical in sizes 2, 3 and 4.
The usual range of accessories was offered which, although not as extensive as that listed by the competing Italian milling machine makers Riva, was still useful: a range of vertical heads including a high-speed unit with both a quick-action lever and worn-and-wheel driven fine feeds to the quill; heads to accept milling cutters for gear-production work; bolt-on and self-contained spherical universal milling attachments; a powered overarm to convert horizontal millers to vertical ram types; slotting heads; rotary tables in plain and tilting forms; universal dividing heads; plain, swivel base and tilting machine vices; vernier ruler to fit on all three feed axes; optical measuring devices; precision length-rod holders, etc.
In order to extend this section, the writer would be interested to hear from any reader who has access to Arno or Nomo sales literature..

Model "0" Universal
Even though it was the smallest machine in the range, the 1-ton Model "0" was still well specified and built with its internally ribbed main column and base cast in one piece - the lower section incorporating a coolant tank with fluid lifted by a 1/2 h.p. electric pump. Held inside the base of the column, on an adjustable plate, the 2 h.p. electric motor drove up to the spindle by triple V-belts, a multi-plate clutch providing the operator with a sensitive means of engaging and disengaging the drive. The spindle gearbox, lubricated by splash and fitted with an oil-level window, held gears and splined shafts of high-quality steel that had been hardened, tempered and ground. Running on adjustable, precision-grade taper-roller bearings, the horizontal spindle had a No. 30 I.S.T. nose and 12 speeds from 25 to 1000 r.p.m. - control being by the juxtaposition of three levers on the right-hand face of the column. By the end of WW2 most industrial milling machines had switched from round to rectangular dovetail overarms and the Arno was no different, its heavy, box-section arbor support sliding in wide, dovetail ways and supporting a 1-inch diameter cutter arbor.
With 1/2" T-slots on 3-inch spacing, the 39.5" x 9.5" table had 24.5" of longitudinal travel under power (25" by hand), 7" in traverse and 15.25" vertically. 12 rates of automatically disengaged power feed from 3/8" to 14" per minute were provided for the longitudinal feed only, with all moving parts completely enclosed - there being no open universally-joined drive shaft to catch clothing. As a "Universal" miller the table could be swung - 45-degrees each way from central. Table and knee ways (the latter of square section) were lubricated by a hand-operated pump drawing oil from a reservoir, complete with level glass, built into the front section of the saddle..

Arno Models 1.V and 1.VR Vertical
A substantial , general-purpose vertical milling machine weighing 23 cwt., the V.1 had a 43.25" x 10" table with travels of 32" longitudinally, 9" in traverse and 16.5" vertically. 12 rates of power feed from 15/32" to 15.75" per minute were fitted to all movements, the makers considering (in contrast to most competitors) that such a wide range did not need modifying according to the direction of travel. If rapids were required  the Model Designation became 1.VR. The table drive system was fully enclosed with no exposed rotating parts. The stiff, internally ribbed main column was cast as one piece with the foot, the latter doubling as the coolant tank with  flange-mounted 1/4 h.p. electric pump. Mounted on a swinging plate inside the base of the column was a 3 h.p. electric motor that drove the spindle via a multi-plate clutch and a splash-lubricated, 12-speed all-roller-and-ball-bearing gearbox holding gears and splined shafts of high-quality steel that had been hardened, tempered and ground.  Speeds, arranged in geometrical progression, spanned 30 to 1200 r.p.m.
Able to be tilted 45 degrees either side of central, the vertical head held a spindle fitted with a No. 40 INT nose that ran in high-precision taper roller bearings and had 3.25" of travel under the control of a fine-feed handwheel. As option (an extra £275 in 1963) the head could be fitted power down-feed..

Arno Models 2.V and 3.V Vertical
Heavy-duty and powerful vertical millers, the 2.V and 3.V were of identical mechanical layout but with significantly different capacities. Equipped with a 51" x 12.5" table with 37.5" of longitudinal travel, 11" in traverse and 17.75" vertically, the 4850 lb. 2.V had a separate 3.5 h.p. power-feed motor that gave 24 rates set appropriately for the direction of travel: 0.117" to 34.5" longitudinally; 0.94" to 29" in traverse and from 0.70" to 21.5" vertically. Rapids were available in all directions set respectively at 125", 98" and 76" per minute. Driven by an 8 h.p. motor held in the base of the main column, the No. 50 INT spindle had 3.125" of travel by fine-feed handwheel and, on early models, 12 speeds from 20 to 810 r.p.m. later altered to more useful 30 to 1200 r.p.m. Like all Arno millers the drive passed though a multi-plate clutch and a splash-lubricated gearbox with hardened, tempered and ground gears and splined shafts running in ball or roller races.
Some 45% heavier than the 2.V at 7050 lbs, the 3.V was a very much more massive job and mounted a huge 63" x 15" table with travels of 51.25" longitudinally, 14.5" in traverse and 21.625" vertically. Driven by a 5 h.p. motor, the number of feeds was reduced to 16, all set one rate of 0.281" to 22" per minute - as were the rapids, at 79" per minute. A 12 h.p. motor drove the 57/8" travel No. 50 INT spindle at 20 speeds spanning 30 to 1200 r.p.m. - though earlier versions (as on the V.2) may well have been set slower at 20 to 810 r.p.m..

Arno Models  No. 2 and No. 3 Universal
Built along identical lines - but each built and fitted appropriately for their anticipated workload - the No. 2 and No. 3 Universal millers were intended for both general workshop and production use. Fitted with a 47.5" x 11.75" table (later  51" long) able to be swung 45-degrees each way from central, the Arno No. 2 had 24 rates of feed (driven from a mechanical extension to the 5 h.p. spindle motor)  from 1/32" to 18" per minute longitudinally and in traverse and at 1/64" to 9" per minute vertically. Rapids were fitted to all feed directions at the rate of 34" per minute along and across and 20" vertically. Fitted with a No. 50 INT nose the spindle ran in high-precision taper roller bearings and had 12 speeds from 25 to 1200 r.p.m.
Weighing a considerable 7000 lbs (3 tons) the No. 3 carried a 57"" x 15" table (later lengthened to 63" and then 64") with travels of around 51" longitudinally, 14.5" in traverse and 215/8" vertically. 16 rates of feed were provided, driven from an extension to the main 10 h.p. spindle motor, with  all three directions of travel set at the same 1/4" to 22" per minute. Fitted with a50 INT nose, the spindle had 16 speeds from 22 to 1200 r.p.m. and drove a 1.25" cutter-holding arbor..

Arno No. 4 Vertical
A heavy,  general-purpose vertical milling machine, the V.4 had a 43.5" x 10" table with travels of 28.5" longitudinally, 8.5" in traverse and 14.5" vertically. 12 rates of power feed from 15/32" to 15.75" per minute were fitted to all movements - identical rates being listed - at least on early models - for each direction. Fitted with a No. 40 INT spindle, the head had 12 speeds from 25 to 1000 r.p.m.