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TOS Zbrojovka FA3 Milling Machines


TOS FN Universal Millers

For the FA3 an Operation & Maintenance Manual can be
supplied together with a Parts Manual

From the late 1940s onwards, based in what was then a communist, state-controlled Czechoslovakia, the TOS/Zbrojovka/Skoda machine tool group offered a bewildering variety of products amongst which were dozens of different milling machines. However, one of the most popular and widely distributed was the FA range, consisting of the FA3 (described below), FA2, FA4 and FA5, all conventional knee-type machines with sales handled,  initially, through Elgar Machine Tools of Feltham, Middlesex and then by the much larger Selson Group.
All four sizes of the FA were available in three forms: a horizontal machine the "H"; as a "Universal", the "U" (fitted with a table able to be swung 45 in each direction from central) and as a robust vertical, the "V", that used the table and knee assembly from horizontal combined with a swivelling vertical head whose quill was driven by a fine-feed handwheel - but no quick-action drilling lever. Although all three sizes of machine shared a common layout, there was no attempt by the makers to stretch a smaller model into a larger; each was a novel construction with different main castings, table sizes, spindle speeds, motor sizes and table-feed rates. As was normal on this type of miller from all makers, the Universal was equipped, as standard, with the facility to couple a power drive to both a universal dividing head as well as various sizes of rotary table.
Over the years a number the millers developed and offered in other versions that included the FA3AH, FA3B, FA4AH, FA4B and FA5AH, FA5B; these notes concern only the earlier models.
Continued below:

TOS Zbrojovka FA3-V Vertical

Next to smallest in the range, the FA3V, FA3H and FA3U all had a table 250 mm wide by 1250 mm long with three 14 mm T-slots on a 55 mm spacing and both power and "rapid" feeds longitudinally and - in contrast to the FA2 - also in traverse and vertically, all movements being powered by a separate 740 kW (1 h.p.) 1380 r.p.m. motor. Flange mounted against the rear of the feed gearbox, fitted at the left-hand side of the saddle, drive from the motor was initially through a pair of bevel gears and then via multi-plate clutches with overload protection with a single, spring-loaded directional lever on each axis providing the control. Travel stops were not mechanical but electrical, their activation stopping the motor.
Longitudinal travel was 810 mm by hand and 800 under power and, respectively, across 280 and 270 mm and vertically 410 and 400 mm. Thirteen rates of power feed were available, these ranging from 14 to 900 mm/min both longitudinally and across - the full range being: 14, 20, 28, 40, 56, 80, 112, 160, 224, 315, 450, 630 and 900. Vertical rates were set at 25% of the others, being from 4 to 250 mm/min. Rapid traverses were set at 2800 mm/min longitudinally and across and at 800 mm/min vertically. Table power-feed controls - selection of direction, engagement and rate were all duplicated at the rear of the saddle at its right-hand end, so allowing the machine to be operated from the rear of the table - a possible bonus on some long or awkwardly-shaped jobs.
Positive lubrication of the feed speed-change gearbox was by a piston pump, the recirculating supply also able to be directed (unfortunately not automatically but by pressing a handle), to send oil to the table feed screws and their support bearings and the sliding surfaces of table, saddle and knee - though the column surfaces of the latter, and the bearings of the table's longitudinal feed screw, were lubricated through grease nipples. The heavily loaded knee screw was lubricated by an oil bath and, copying established Cincinnati practice, when normal or rapid feeds were engaged by a circulating supply.
Both horizontal and vertical spindles were mounted on their noses in a precision-grade, double-row roller bearing with a tapered bore that allowed a very precise adjustment to be made of the running clearance. Spindle nose fittings listed as being available included an ISA 44, metric 32 and No. 4 Morse - though doubtless others would have been supplied to special order.
Able to be swivelled 45 each side of upright, the vertical head had a quill with a fine-feed travel of 75 mm with, instead of a screw-type adjustable depth stop, a telescopic design that was also connected to a dial indicator. In addition, for very precise work, it was possible to fit slip gauges into the stop mechanism.
Drive to both vertical and horizontal spindles came from a low-profile, 1430 r.p.m.  5.7 h.p. motor flange mounted against the rear of the main column with control by a forward-reversing switch and "Start-Stop" push buttons - with that for "stop", when held down, bringing in an electrically applied braking effect created by a rectifier supplying direct current to the motor - the system being listed by the makers as being of the "Alnico" type. Motor overload protection was by thermal relays and the operator provided with an Ammeter to gauge how hard the machine was working.
Twelve spindle speeds were available, these being generated by a gearbox held within the main column and operated by two levers: one rotary the other quadrant. The speed range was identical for all three models: 45 to 2000 r.p.m. as standard but with the option of higher range that spanned 63 to 2800 r.p.m. Lubrication of the speed-change gearbox, spindle bearings and bevel drive to the vertical head was by an electrically driven gear pump.
Coolant was held in the hollow foot of the miller and supplied by an electrically-driven pump. Returning coolant and chips were drained from the table and saddle through broad channels in the knee and then into detachable pans at either side (these holding coarse separator screens), before returning to the base where the compartment was divided into a number of settling tanks.
Electrical contactors, fuses and associated hardware were grouped together in a compartment at the back of the machine, the whole assembly being mounted on a neat, slide-out tray.
Supplied as part of the standard equipment with each new machine were the following: a milling arbor, coolant equipment, a complete electrical installation to the customer's voltage requirements, a grease gun, a set of spanners and an instruction book.
A number of useful extras was offered including a power-driven universal dividing head with tailstock and a support for long work, a power-driven rotary table and, for the horizontal models, standard, universal and circular vertical attachments, a rack milling device and a circular attachment with hand drive. In addition the usual range of machine vices, different diameters and lengths of milling arbor, spindle-nose reducing sleeves and collet chucks, etc..

TOS Zbrojovka FA3-U Universal with swing table

TOS Zbrojovka  FA3-U Horizontal

View showing duplicated controls at the rear of the table

Rack-milling attachments including a special swivel head to hold a horizontal milling arbor

Rack-milling attachment in use

Universal miller with power-driven dividing head (with tailstock) and the maker's standard, non-quill-feed vertical head

Power-driven rotary table on the Horizontal model

Ammeter to gauge load on the motor

Electrical Installation on its slide-out holder

TOS FA2   TOS FA4   TOS FA5   TOS FN Universal Millers

For the FA3 an Operation & Maintenance Manual can be
supplied together with a Parts Manual

TOS Zbrojovka FA3 Milling Machines
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