Of approximately 4" centre height and admitting 20" between centres, the Drummond "4-inch" featured a heavy "beading" around the edges of the bed - a distinctive feature of early Drummond - and some other contemporary lathes - and must have been designed to add some stiffness to the very elegant if rather light casting. Also of assistance in stiffening the structure was a heavy cast-iron chip tray with cut-outs at front and back to give clearance for the round-rope belt. The original drive would have been from a foot-operated treadle and flywheel assembly, almost certainly of the type used on the 3.5-inch flat bed. The layout of the screwcutting arrangements was identical to those on a Mk 1 B Type: a "power shaft", with a dog clutch at the headstock end, ran the length of the bed and engaged a gear at the tailstock end to transmit its drive upwards to the leadscrew that lay between the lathe bed ways. With the leadscrew running directly under the carriage and connected to it by a full nut, forces from the toolpost were able to follow the most direct and least flexible path.
Slide-rest feed screws (and the leadscrew) were all of square-section and arranged to be "cack-handed" i.e. e.g. turning one clockwise would cause the slide to retract rather than advance.; not something to worry about if just the one lathe was in use (it's easy to get used to) but a potential disaster if other machines in a workshop were arranged conventionally
Able to be swung a few degrees in each direction from central, the No. 1 Morse taper headstock carried a spindle that, like many similar lathes from competing manufacturers at the time, was left solid as standard - though hollow ones have been found and would have been charged extra. Spindle bearings were plain and pressed into holes carried on rather slender posts; to retain and adjust them the posts were split downwards, through their lower section, with a tightening bolt that passed through from back to front - the nuts can be see against the small circular bosses underneath each bearing in the pictures above and below. This bearing design was also used on the first of the popular 3.5" flat bed "B-type" machines
If any reader has a Drummond like this (or any other unknown type)  the writer would be interested to hear from you.
Alan Swales, a Drummond 4-inch owner living in Australia writes:
I recently attended the funeral for my wife's cousin and the officiating minister had been for many years a Presbyterian minister in Mosman. He was in his 90's. I chatted with him about "The SPIT" area where we bought our Drummond 4-inch Flat-bed lathe. He said that before the Sydney Harbour Bridge was built, (finished 1932), Scottish immigrants often settled in the SPIT area of MOSMAN and, because it was difficult to get to, the land was cheap - and being Scots, they realised the potential. He could not specifically remember the names of his old parishioners, but thought there was a familiarity to the name DRUMMOND.
While this is not solid evidence, it leads me to consolidate my idea that we bought our lathe in probably 1945 from relatives of Arthur Drummond who were disposing of his old machinery. The fact that the lathes were in a garage under the house, that there was a lot of other machinery of similar nature stored there - and that parts to suit our lathe were obtained from boxes of stuff under the house -  leads me to believe this story.
I have been unable to obtain municipal records to confirm my story, but I believe they must exist somewhere.
The lathe you have shown on the internet has an identical motor to the one that came with ours, a MAYTAG washing machine type from around 1935..

The leadscrew dog-clutch operating handle protrudes through the bed immediately below the gap. Underneath is an unnecessary bolt-on support plate - removed from the smaller "B-type" lathe in 1907.
Just visible at the front of the headstock casting is the slotted boss that allowed the headstock to be swivelled few degrees in either direction from the centre; also clearly shown, against the machined circular section, is the nut on the end of the bolt that passed beneath the bearing to adjust it.

The tailstock and leadscrew-drive gears are almost identical in shape to the smaller machine. Instead of a crude bolt bearing down directly onto the tailstock barrel to lock it, it appears that a change has been made to a slit in the back of the  casting closed down by a through bolt fitted with a handle.

The changewheels are mounted on an L-shaped bracket - with an additional slotted bracket on the headstock to carry the stud and gear necessary to cut left-hand threads. The screwed gear-retaining ring on the end of the spindle has been put on the wrong way round.