Developed from earlier models with rounded styling typical of the 1950s, the TOS range of Type FN precision universal milling machines was built in several versions including, on this page, the FN20, and FN32 while another version, the early Deckel-like FN22 was not updated. Later models, with more angular lines, continued to be manufactured into the 1980s in what was then the communist-controlled Czechoslovakian Republic. Several special versions were also offered, though these - for example the FNGJ-20, FNGJ-32, FN-32NC - differed only in the fitting of optical or digital read-out systems.
Although the general arrangement of the miller followed that used by many other makers of similar types* ( a Universal Precision Milling Machine) in regard to the design of the horizontal spindle and the mounting of vertical heads, it followed more closely those made in other countries then behind the Iron Curtain: the Russian 676Π and Polish "Avia". Although the range of accessories did not quite match that offered by Western makers of similar models - there being, for example, no specialised milling attachment for intricate corner work or a high-speed head with fine down-feed - this was a very substantially constructed (1750 kg) precision miller offered at a price many thousands of pounds below that of the competition.
Like all of its type* it mounted, on top of the main column, a sliding housing containing a horizontal spindle driven by gear from a parallel shaft below. To the end of this could be fitted a variety of vertical milling and slotting heads and, above it, an overarm to support a horizontal cutter-holding arbor.
With a vertical, T-slotted knee some 1160 x 260 mm and fitted with five 12/21 mm T-slots on 45 mm spacing, the front of the machine was intended to accept a choice of two rectangular tables - one plain and the other able to be inclined, tilted and swung and fitted with an in-out feed. Two motors were fitted: one, of 2.2 kW, was used to drive the cutter spindle; the other, of 1.8 kW, the table-feeds' gearbox - both drives passing from motor to gearbox using double V-belts. Running in high-precision roller bearings (types NN-3010K and NN-3007-K), the ISA 40 horizontal spindle was made from a hardened and ground alloy steel and dynamically balanced - with axial loads were taken by two spring-loaded thrust bearings. Driven from a demountable, self-contained column-mounted gearbox holding hardened and ground gears (held on shafts running in ball and roller races), the spindle had 18 speeds that spanned 40 to 2000 r.p.m. With a power-feed by roller chain, the overhead spindle had 300 mm of travel - but an additional 10 mm when moved by the handwheel.
As part of the standard equipment, the miller was fitted with a generously-sized plain horizontal table of 1000 x 400 mm with eight T-slots. Rather unusually, mountings were provided on both front and back surfaces, one face having provision for six retaining bolts, the other for eight. As an optional extra (and one essential to get the best out of the machine) was a 360 x 360 mm Universal Table with a cross traverse by screw - the latter fitting increasing the range of the head's horizontal traverse by additional 200 mm. The table could be swivelled about its vertical axis within a range from 0 to 360 degrees, tilted horizontally by 45 degrees in each direction and by 30 degrees from level front to back. Positioning was by a large micrometer dial and the use of built-in fittings to accept dial indicators and gauge blocks. Table travels were 700 mm horizontally and 400 mm vertically under power (an additional 10 mm was available if moved by hand) with all traverses equipped with adjustable knock-off stops and provision to mount dial indicators and precision gauge blocks. The number of feeds and their rate were identical to those used on the head: 18 from 8 to 400 mm per minutes with rapids (in both directions) at 1240 mm per minute. As a safety precaution, the feed was taken through a "ball clutch" - any sudden overload (the maximum permitted torque was set at the factory) caused the drive to slip.
Able to be rotated through 360 degrees, the Type SH ordinary vertical head had an ISA40 spindle nose and a quill travel - under the control of a detachable lever - of 90 mm and 18 speeds ranging from 40 to 2000 r.p.m. With the same spindle travel, the self-contained motorised High-speed Head Type FP was driven by V-belt and had speeds from 200 to a useful 10,000 r.p.m. Dividing was taken care of by a robust, swivelling Universal Diving Unit that could be mounted on any of the tables, including the vertical. The ISA40 spindle nose could be set a maximum distance of 375 mm from the end centre and the unit swivelled away from the vertical position to the right and left by 90 degrees, swivelled towards the machine by 15 degrees and away from it by 10.
A low-line 380 mm diameter rotary table able to be mounted either horizontally or vertically was available; equipped with 8 radial T-slots it could be indexed through 24 direct divisions by plunger with indirect indexing from 2 to 360 degrees
For slotting TOS offered the usual type of head that could be rotated through 360 degrees; its stroke was adjustable over a range from 0 to 100 mm with 14 rates of double strike from 10 to 200 per minute.
*Proof of the type's success - the genus Precision Universal Milling Machine - is evident from the number of similar machines made in various countries including:
Austria: Emco Model F3
Belgium: S.A.B.C.A. Model JRC-2
Czechoslovakia: TOS FN22, TOS Model FN20, 32 & FN40 Optic
Spain: Metba Models MB-0, MB-1, MB-2, MB-3 and MB-4)
England: Alexander "Master Toolmaker" and the Ajax "00", an import of uncertain origin.
France (?): Perron Montier
Germany: by several companies including: Macmon Models M-100 & M-200 (though these were actually manufactured by Prvomajska); Maho (many models over several decades); Thiel Models 58, 158 and 159; Hermle Models UWF-700 and UWF-700-PH; Rumag Models RW-416 and RW-416-VG; SHW (Schwabische Huttenwerke) Models UF1, UF2 and UF3; Hahn & Kolb with their pre-WW2 Variomat model and Wemas with their Type WMS.
Italy: C.B.Ferrari Models M1R & M2R; Bandini Model FA-1/CB and badged as Fragola (agents, with a version of the Spanish Meteba).
Japan: Riken Models RTM2 and RTM3
Poland: Fabryka Obrabiarek Precyzyinych as the "Avia" and "Polamco" Models FNC25, FND-25 and FND-32
Russia: as the "Stankoimport" 676
Spain: Metba Models MB-0, MB-1, MB-2, MB-3 and MB-4
Switzerland: Aciera Models F1, F2, F3, F4 and F5; Schaublin Model 13; Mikron Models WF2/3S, WF3S, WF-3-DCM & WF-2/3-DCM; Christen Types U-O and U-1 (and Perrin frères SA, Moutier) and Hispano-Suiza S.A. Model HSS-143.
The former Yugoslavia: Prvomajska (in Zagreb with Models ALG-100 and ALG200); Sinn Models MS2D & MS4D; Ruhla and "Comet" Model X8130, imported to the UK in the 1970s by TI Comet.
At least five Chinese versions have been made, including one from the Beijing Instrument Machine Tool Works. A number of the "clones" merely followed the general Thiel/Maho/Deckel concept whilst others, like Bandini and Christen, borrowed heavily from Deckel and even had parts that were interchangeable. Should you come across any of these makes and models all will provide "The Deckel Experience" - though you must bear in mind that spares are unlikely to be available and, being complex, finely-made mechanisms they can be rather difficult and often expensive to repair..