Totally enclosed, the dual Metric/English screwcutting gearbox was lubricated by an oil bath and fitted with hardened and ground gears running on ball-race supported shafts. Three conventional levers, and a 6-position joystick that moved into radial slots around a circle, swapped the ratios. The box was able to generate a wide range of pitches without dismounting or changing any of the changewheels; the range of threads comprised: 40 Metric from 0.4 mm to 14.0 mm; 18 Module from 0.3 to 3.5m; 38 English from 2 to 72 t.p.i. and 27 Diametral from 8 to 60 D.P. The range of sliding feeds varied from 0.002" to 0.032" (0.06 mm to 1.0 mm) and surfacing feeds at half those rates (and thus) from 0.001" to 0.016" (0.03 mm to 0.5 mm) - all per revolution of the spindle.
Doubled walled, the apron had all its shafts supported on ball bearing at each end and the gears hardened and ground; the base was closed off to form an oil bath to splash lubricate the internals and, at the top of the front face, just to the right of cross-feed screw, was a rod that needed pushing in to operate a plunger pump to feed the same lubricant to the bed, cross-slide ways and cross-feed nut.
Selected by a push/pull button, the power feeds were positively engaged by a lever that allowed the feed to be stopped instantly, regardless of how deep and heavy the cut. A second push/pull button provided a means of reversing either feed - with a knurled-edge dial, on the apron's right-hand face, to allow the operator to adjust the trip force that disengaged the feed as it was moving to either left or right. This arrangement providing a handy means of obtaining maximum accuracy when turning up to a shoulder length. A thread-dial indicator was fitted as standard.
The carriage traverse handwheel could be pulled out to disengage it when power feeds were being used - a feature that was included from the very first models.
Machined all over, the compound slide rest was fitted with taper gib strips that allowed a very precise fit to be obtained - and gave far superior support in comparison with the cheaper "loose-strip" type. The 11-inch travel cross slide was especially wide and fitted with a cross-feed screw that could be adjusted to reduce backlash; although the slide was devoid of T slots and tapped holes - and so appeared, at a glance, to be incapable of mounting any accessories - the edges of the slide were machines to accept slide-on T-slotted and plain blocks that could hold a variety of items including hydraulic profiling units, and parting-off and other special tools.
With 9-inches of travel, the set-over tailstock's hardened and honed No. 5 Morse taper barrel wasengraved with metric and inch graduations and carried a useful zeroing micrometer dial on the feed handwheel.
Constructed around two heavy cast-iron plinths, the stand had a deep slide-out chip tray between them. Surprisingly, it offered no storage at all, in either plinths or centre section, even though this would not have been difficult to engineer - and would have made life both easier and more productive for the operator.
All but the most perverse would have been happy with the combination of feed and leadscrew combinations offered by the maker, for the lathe was available with an English-pitch leadscrew with feed screw micrometer dial graduations in inches or millimetres, or with a Metric leadscrew
Standard equipment was fairly sparse (no 3-jaw was supplied) and consisted of a centre adapter to sleeve down the spindle nose, two No. 5 Morse centres, a simple slotted toolblock to accept one turning tool, driving plate, thread-dial indicator, spanners, oil can, an accuracy and inspection and a very useful combined instruction and parts book that showed the whole machine as a set of exploded component diagrams.
Accessories included both a dynamically balanced "Super-precision" ductile-iron 12.5-inch (315 mm) 3-jaw chuck with a hardened and ground scroll and a 16-inch (405 mm) ductile-iron heavy-duty 4-jaw chuck both specially made by the Burnerd company. A chuck guard, a telescopic taper turning attachment, a 20-inch (430 mm) faceplate for use on straight-bed lathes and a 27-inch (686 mm) faceplate for gap-bed models, a zeroing micrometer dial on the carriage handwheel; a single-type bed stop, a 5-position indexing bed stop and a micrometer bed stops; a fixed steady with a capacity of 9 inches and a choice of plain or roller-bearing fingers; a 3-inch capacity travelling steady with a choice of plain or roller-bearing fingers; 4-way automatic ratchet-indexing and Dickson-type quick-set toolposts; dual metric and inch micrometer dials, a "longitudinal-travel" dial indicator, an Ainjest quick-threader attachment, T-slotted and plain blocks to locate over the cross slide and mount standard or quick-set rear toolholders, a high-precision, heavy-duty rotating centre, a low-volt light unit and a full-length splash back.
The 40-inch between-centres Mastiff 1400 was 98 inches (2520 mm) long and weighed 5110 lbs (2320 kg)
the 60-inch between-centres lathe was 118 (3030 mm) inches long and weighed 5440 lbs (2470 kg)
the 80-inch between-centres lathe was 138 inches (3535 mm) long and weighed 5770 lbs (2620 kg)
the 100-inch between-centres version was 158 inches (4045 mm) long and weighed 6350 lbs (2880 kg)
the 120-inch between-centres version was 178 inches (4045 mm) long and weighed 7160 lbs (3250 kg)
All were the same width - approximately 42 inches (1070 mm) from front to back.
Details of the Mastiff 1400 replacement, the Mastiff VS1800 can be seen here.