To solve the problem of how to drive the spindles when their housings were moved forwards and backwards (to provide lateral travel to the cutter), the topmost gear of the column-mounted speed-change gearbox was made very long and a small gear, fitted to the first of the overhead rams, allowed to slide along it. In turn, this gear protruded above the top face of the casting so that a splined shaft, held within the uppermost ram housing (and connected to the head at the front end by bevel gears), passed through its centre and allowed the gear to slide as the head was moved to and fro.
Besides normal horizontal and vertical milling operations, all models were available with a range of accessories to cover slotting, jig boring, jig grinding, spiral milling and punch milling. In respect of these operations, an important part of the machine's versatility was dictated by the multi-angle, swivelling and tilting table and indexing attachments; a machine with just the plain table and standard vertical head available remained very useful, but it was not possible to enjoy, in full, all its ingenious capabilities.
Arranged to drive both the milling spindle and the feeds to the head and table, the main motor fitted to the standard 158 was a single-speed, 3-phase, 2.2 h.p. 1500 r.p.m. type mounted inside the column at the back with drive by, at first 2 and then later 3 external V-belts (guarded by a full-height cast-aluminium cover) to the input pulley of the speed-change gearbox. Positioned in the column below the spindle-speed gearbox, the table and head-feed gearbox (on the ordinary version) 158 had eight speeds that gave feed rates (for horizontal, vertical and head in-out travels) of 9.5, 16, 25, 32, 45, 90, 100 and 160 mm/min. On all models the gears were hardened and ground, ran on multi-splined shafts and were lubricated by an oil bath.
Although the table feed rates were independent of the spindle-speed settings (any combination of speeds and feeds was possible), the arrangement could not provide a "rapids" travel and, to allow this, Thiel offered another version, the 158S, a type equipped with a separate motor to run the feeds' gearbox while also providing a rapids feed rate of 900 mm/min. The feeds on the S could be reversed while running and rapids selected at any moment or position simply by depressing a red-painted lever - simply releasing the lever stopped the feed. Table feeds were engaged by a pair of long levers, one positioned at each side of the knee and so allowing operation from either end of the table--or even from behind. Automatic table stops were, of course, provided and all drives protected by easily accessed shear pins. Table travels (which were not shortened by use of power feeds as on so many other makes) were 310 mm left to right and 400 mm vertically; the in and out feed (provided, of course by the ram head), was 200 mm. Feed screws on all three exes were precision ground, ran though substantial bronze nuts and were turned by large handles that provided exactly the right degree of "feel". Micrometer dials were huge, finely engraved, satin-chrome finish and equipped with vernier scales. Built-in steel rulers were provided for each axis of movement which, in combination with the standard-fit holders to accept dial-test indicators and gauge blocks, allowed high-precision measurements by co-ordinates to be made, independent of the feed-screw readings.
Provided in a correct geometric progression, the 12 spindle speeds spanned a useful: 60, 80, 106, 140, 180, 240, 320, 470, 536, 700, 920 and 1200 r.p.m. Fitted with a sliding commutator, when switched off the motor provided a braking action that stopped all rotating feeds - as there was no idle time to the stop point, safety was considerably increased. Motor control for start, stop, brake release and jog was by push buttons with reverse selected by a separate lever. Case hardened and ground all over, the horizontal spindle ran in high-precision taper roller bearings that provided both excellent support and an easy means of adjustment.
Although the range of heads was not as wide as that offered by Deckel, a good basic range was available with, for horizontal use, an overarm and drop bracket to hold a milling arbor - both being supplied as part of the standard equipment. Also provided with each new machine was a 360° swivelling milling and drilling head, this being powered by the machine's own drive system and fitted with a No. 40 INT nose with a collet capacity of 25 mm. The quill travel was a reasonable 90 mm (and it was possible to space the centre line of its cutter a maximum of 700 mm away from the inaner face of the column). 12 speeds were provided, these being geared up from the horizontal drive to give a useful: 90, 120, 160, 210, 270, 360, 480, 705, 805, 1050, 1380 and 1800 r.p.m. Speed changes were made by three concentric dials on the columns right-hand face, this modern arrangement (as first used on Cincinnati "Dial-Type" millers) replacing the externally-mounted box with a pair of quadrant levers used on the Model 58.
To aid the drilling of small holes and the use of tiny milling cutters, a special 0.5 to 5 mm collet capacity head was available with a second spindle mounted parallel to the first and geared to give 6 useable speeds of 1720, 2240, 2920, 3840 and 5000 r.p.m. The maximum quill stroke by lever (no fine feed by handwheel was fitted) was 40 mm.
When a lot of jig, or high-precision boring or drilling was envisaged, a special automatic down-feed head (Attachment N. 7) was provided. This could be swivelled through 90° each side of vertical, had a spindle with a No. 5 Morse taper nose socket, a slide traverse of 150 mm (under power or by a hand lever) and 12 speeds from 90 to 1800 r.p.m. Three rates of power feed were fitted: 0.03, 0.06 and 0.12 mm/min. - all able to be engaged, disengaged or changed at will during as run
For slotting, the usual king of head was provided: this could be swivelled through 360°, had 8 stroke rates of 34, 45, 60, 78, 100, 135, 180 and 235 per minute with a stroke adjustment range from 0 to 80 mm and a slide adjustment of 40 mm.
Unlike many makers who charged extra, fitted as part of the 158's standard equipment was a 700 mm x 260 mm table that could be tilted backwards and forwards through 30° and rotated in a horizontal plain through the same angle. Other tables available at extra cost included Attachment No. 9, a special large unit 390 x 820 mm with 5 T-slots each 14 mm wide - the table able to be moved across the vertical mounting table either way by 100 mm. A similar accessory to the standard tilting table was a 800 x 270 mm unit that incorporated a screw-driven cross slide with 130 mm of travel measured by a very large micrometer dial with a vernier scale. In addition to the 30° of forwards and backwards tilt and rotation in a horizontal plane through 30° this table (Attachment No. 12) could also be swivelled about its horizontal axis by 90°. With care, the makers claimed that setting accuracy to be within 6 minutes of arc could be achieved.
Available to fit any table was a horizontal swivel sub-table with a working surface of 130 x 800 mm with a single, central 14 mm T-slot. Amongst the standard equipment included with every Thiel 158 was a variety of equipment that allowed it to be pressed into service immediately: a universal swivelling and tilting table, a vertical milling head (Attachment No. 5) a universal dividing head (Attachment No. 1), an overarm for holding horizontal milling arbours complete with bushed drop bracket, built-in precision rulers, slip gauge platforms, 3 dial-test indicators, complete coolant equipment with pump and piping, a standard off-set boring head, a centring device, 1 short and 1 long milling arbor to hold cutters, 1 collet, Morse taper sleeves No. 2 and No. 3, 2 collet spanners, drill chuck, 3-jaw chuck on a collet mount and with 2 sets of spare jaws, swarf tray, Low-voltage light unit with a 50V transformer, grease gun, two drain pipes for the coolant system and the necessary fixing bolts, spanners, handles, dividing tables and an instruction book..
*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 FN Models England: Alexander "Master Toolmaker" and the Ajax "00", an import of uncertain origin. Germany: Hahn & Kolb with their pre-WW2 Variomat model Wilhelm Grupp Universal- Fräsmaschine Type UF 20 N/120 Hermle Models UWF-700 and UWF-700-PH Leinen Super Precision Micro Mill Macmon Models M-100 & M-200 (though these were actually manufactured by Prvomajska); Maho (many models over several decades)
Ruhla Rumag Models RW-416 and RW-416-VG SHW (Schwabische Huttenwerke) Models UF1, UF2 and UF3 Thiel Models 58, 158 and 159 Wemas Type WMS Italy: C.B.Ferrari Models M1R & M2R Bandini Model FA-1/CB and badged as Fragola (agents, who also sold a version of the Spanish Meteba). Japan: Riken Models RTM2 and RTM3 Poland: "Avia" and "Polamco" Models FNC25, FND-25 and FND-32 by Fabryka Obrabiarek Precyzyinych Russia: "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 Christen and Perrin Types U-O and U-1 (Perrin Frères SA, Moutier) Hispano-Suiza S.A. Model HSS-143 Luthy Mikron Models WF2/3S, WF3S, WF-3-DCM & WF-2/3-DCM Perrin Type U-1 Schaublin Model 13 and Model 22 The former Yugoslavia: Prvomajska (in Zagreb with Models ALG-100 and ALG200) Sinn Models MS2D & MS4D "Comet" Model X8130, imported to the UK in the 1970s by TI Comet. Sloane & Chace in the USA produced a miniature bench version and at least five Chinese-built models have also 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..