Bridgeford flat-belt drive 26-inch and 30-inch heavy-duty lathe
Both lathes were of thoroughly conventional design - albeit of good quality and massively built - and each, apart from the tuning capacity, of identical specification.
The headstock drive was by either a three-step pulley to take a 5" wide belt, or a 4-step to run a 4" belt. The wider belt was able to transmit greater power, but limited the number of speeds to nine, whilst the narrower belt gave twelve speeds - in both cases the range was from 6 to 260 rpm.
The 14 : 1 ratio backgear was of the double-reduction type with the main components cut from steel forgings. The 4.5" diameter by 7.5" long front and 3.25" x 5.5" rear spindle bearings were in bronze with the 2.125" bore, No. 6 Morse taper spindle in forged high-carbon steel; oil was fed to the spindle from sumps contained within the base of the headstock.
With parallel top and bottom edges and of deep section with cross ties forming rigid box sections between the front and back walls, the bed had conventional V and flat ways. It was supported on unusually long cast box-section feet and, in its longer bed versions, supplied with intermediate legs cast as part of the main structure. Beds of any length could be provided in two-foot multiples, each of which occupied an extra 20 cubic feet - and weighed 850 lbs.
To brace the tailstock under very heavy cuts it was provided with a pawl, handing from its base, which engaged with a rack cut from a cast-in rib which ran between the walls. The tailstock was assisted along the bed by a hand-operated gear drive - which engaged against the carriage rack - and clamped in place by four bolts closing down on two locking plates.
Of simple design the carriage had independent clutch-engaged controls inside the double-wall apron for the sliding and surfacing feeds - power for which was taken from a slot in the leadscrew rather than the separate power shaft that might have been expected on a lathe of this size.. The cross slide was mounted in the middle of the saddle - the latter, when a cut was being taken close to the faceplate, able to run well past the front and back walls of headstock and so provide a very solid support for the tool. The micrometer dials were, like most other lathes of the time, far too small.
A Norton-type quick-change gearbox was fitted with threads from either 1 to 14 t.p.i or 2 to 28 t.p.i.
In its 10-foot bed form the lathe weighed 9,900 lbs and was supplied as standard with a screwcutting gearbox, 13" and 30" diameter faceplates, a 7-inch capacity fixed steady, a dial-thread indicator and a complete "self-oiling" countershaft.