The Binns & Berry 12.5-inch centre height model TB Mk. 1 admitted 7 feet 6 inches between the centres on its 12 foot long bed - but both longer and shorter bed machines could be built to special order.
The bedways were of traditional English flat section, 19 inches wide, with the slide ways chilled to provide a dense, close-grained structure which was hand scraped to close limits. The detachable gap piece was held into the 17-inch deep bed by a single bolt between the ways and, when removed, allowed material up to 44 inches in diameter and 12 inches thick to be turned; the cross slide was arranged to allow up to 41 inches in diameter to be turned without having to reset the tool.
The carriage was a complex affair which could be moved under the influence of the leadscrew for screwcutting, the power shaft for power sliding and surfacing or by an electrically-assisted quick return which was independent of the other controls (but interlocked to the power feeds) and allowed the assembly to be returned with just a single movement of its control lever, conveniently positioned just behind the manual carriage handwheel.
The main spindle was, as usual for the company, turned and ground from a solid carbon-steel forging and held in Timken taper roller bearings - in this case two immediately behind the nose - with a single roller bearing for support at the other end. The spindle was bored to pass a 4-inch diameter bar and fitted with a giant No. 5 Morse taper centre, together with a sleeve-down bush; unfortunately, the fitting on the end of the spindle was not an industry-standard American "L" Series Long -taper or Cam Lock, but a simple 10-inch diameter flange to which chucks and other fittings could be (laboriously) bolted. The remainder of the headstock gearbox was filled with gears hammer forged from either carbon steel or heat-treated nickel chrome with the sliding gears having rounded teeth; the supporting shafts were in carbon steel, ground all over and supported in ball or roller bearings complete with central supports. Where gear shafts protruded through the wall of the headstock casting, were fitted, as was usual for a Binns & Berry lathe, with "Angus" oil seals.
The lathe was driven by either a 1500 rpm 12.5 hp motor or, optionally, at a slight extra cost, a 10 hp 1000 rpm motor; the motor mount was an adjustable platform behind the headstock and the drive was transmitted by 6 V belts into a Taylor-patent multi-disc clutch built into the headstock's 15-inch diameter input pulley; the clutch control on the headstock was duplicated on the saddle. 8 spindle speeds were available: 15, 26.4, 43.5, 75.5, 121.5, 208.5, 346 and 600 rpm when fitted with the 12.5 hp motor and 10.3, 17.6, 29, 50.5, 81, 139, 231 and 400 rpm from the 10.5 hp version.
Screwcutting (from a 2.25" diameter 1/2" pitch leadscrew) was provided by a conventional Norton-type quick-change gearbox able to provide 50 different English threads; the 50 different feeds available for power sliding and surfacing ranged from 0.003" to 1.00" per rev. for surfacing and 0.005" to 0.154" per rev. for sliding. A "tumbler change" unit was built into the gearbox, and allowed feeds to be changed without stopping the lathe; constant-loss lubrication was piped to the gearbox bearings through pipes joined to a supply tank located under the tooltray on the top of the gearbox.
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The compound slide rest was of conventional pattern, although the top-slide swivel fitted with a vernier scale by which means it could be located to within 3 minutes of arc. The apron, of double-wall construction, was provided with a detachable front cover through which maintenance and servicing could be carried out; however, although all the necessary points on this relatively complicated structure could be easily lubricated, no centralised pump-driven oiling system appears to have been  fitted (which could also have fed the saddle and cross slide ways) - rather an oversight on such a heavy-duty lathe which was likely to have been put to 24 hour use. One pleasing touch was the provision of wide swarf covers; these extended from the headstock end of the apron and completely covered the ways in close chuck work.
The tailstock was of simple design, with a 3.375" diameter No. 5 Morse taper barrel which went right though the casting (just like a giant Myford ML7). This cumbersome arrangement (whilst satisfactory on a small lathe, it's unsuitable on a large one) was mitigated to some extent by the provision of 3 clamping bolts, the heads of which were accessible at the top of the casting, not hidden away at the back.
The lathe weighed, in standard bed length form, just over 4 tons; its length was around 13 feet, and its width 6 feet 9 inches.
The Type TB lathe was developed through at least three version; a Mk. 3 can be seen here.

Headstock section of the 12.5-inch Type TB Mk.1 showing 6 V-belt drive clutch pulley and the main spindle with two taper roller bearings immediately behind the nose, and a large roller bearing at the opposite end.