Built in Russia from the 1950s until the 1970s, the TB16 was to be found throughout the country installed in most secondary schools as a means of introducing students to lathe work. Instead of being built in one factory, production was shared between several, with each introducing, as time went by, a number of their own small modifications. Although the design closely followed that of the superb Czechoslovakian TOS MN80, owners report that the general execution was poor, with only the main spindle, which ran in two comparatively large 36207 angular contact bearings at the front and one 1206 radial bearing at the back, showing any signs of superior quality or finish. The lathe was normally supplied fitted to a neat, underdrive stand with a double V-pulley pulley on the motor driving down to a 3-step V-pulley countershaft and then up to the headstock to give spindle speeds of: 160, 250, 400, 630, 1000 and 1600 r.p.m. Unfortunately, the lack of a backgear meant that, although a full screwcutting chart was provided, the high bottom speed rather mitigated against the lathe being used for this purpose.
With a massively wide bed (though with only one cross-rib half way down) a centre height of 80 mm and admitting 250 mm between centres, the lathe had changewheel drive through a tumble-reverse mechanism to the leadscrew - the latter running in a solid bronze hanger bearing at the headstock end, a plastic one at the other and grasped by bronze nuts held in a separate carrier. In order to provide a fine feed to the carriage, as on the MN80 (and inspired by the original Lorch design) a planetary gearing system, carried on a 100t changewheel, could be fitted to the end of the leadscrew was fitted, though in this case with exposed gears instead of being neatly enclosed as on the TOS and Lorch. For screwcutting the planetary gear was removed and replaced by a plain 100t wheel. The steel changewheels were guarded by a substantial cast-iron cover, though there was no lock, just a screw closure, and with sufficient room around the spindle hole for young fingers to go exploring. Very strongly constructed, the box-form apron was doweled to the saddle and held reduction gearing for the carriage hand-feed (the rack was also dowelled to the bed for accuracy), a separate, bolt-on holder for the bronze leadscrew clasp nuts and a carriage handwheel fitted with a very large micrometer dial.
Of inferior fit and finish, even by Russian standards, the cross and top slides both had dovetails with evidence of crude milling - through as originally supplied the makers went to the trouble of protecting the top-slide feed-screw with a thin sheet of copper and the cross slide was enormously wide. Felt wipers were used at the end of each saddle wing, secured in place by properly-shaped sheet-metal covers. Running through bronze nuts, all three feed-screws (top-slide, cross-slide and tailstock, ) had M10 x1.5 left-hand threads with the micrometer dials each graduated with 30 divisions. Fitted as standard was a 4-way toolpost with 8 positive index positions.
Of conventional construction, with its spindle bored through 10 mm clear and fitted with a No. 1 Morse taper, the tailstock used a plastic thrust pad and was fitted with a zeroing micrometer dial - though no ruler graduations. Although it was clamped by a proper split bush, the spindle showed signs of hasty machining with the guide slot roughly finished.
Attached to the front of the bed at the headstock end was an electrical control box containing a push-button, no-volt release starter and a rotary switch with four positions: "Off" at 12 o'clock, "forward" at 9 o'clock, "reverse" at 3 o'clock, and "off" at 6 o'clock.
The TB16 appears to have been supplied as standard with an 80 mm 3-jaw chuck, a 4-way toolpost, a "safety" drive plate with a shielded pin, a set of 10 changewheels and Morse taper centres
If any reader has a TB16, the writer would be pleased if you could make contact.