Announced in the Model Engineer Magazine of May 21st, 1908, the Drummond Round Bed "A" Type 4" x 11.25" lathe was to become famous as the most popular machine for generations of British model engineers taking their first tentative - and usually impecunious - steps into the hobby. Publicised, with some fanfare, as the first £5 screwcutting lathe it was manufactured until 1940 using, in that time, three increasingly strong headstock castings and modified spindle bearing - yet with only minor changes to the rest of the specification .Although comparatively inexpensive, and designed to sell at the bottom end of the market, the lathe was not cheapened in any way but built to the usual honest, practical, Drummond standards; even the wheel on the end of the leadscrew having a proper horn-covered handle. The heart of the lathe was the heavy, round, 3" diameter cast-iron  bed, ground to within 1/1000" on an American Norton cylindrical grinder and formed with a bevelled slot along its base. The right-hand thread leadscrew passed through the centre of the bed (of which a 12" longer version was also available) and was engaged by a dog clutch, the operating lever of which protruded through the headstock casting below the front spindle bearing. The end of the leadscrew was fitted with a large, ungraduated wheel for hand operation (the rather-fine handle being made from horn or hardwood) but because the leadscrew had a right-hand thread, this worked in the opposite (cack-handed) sense to normal; turning it clockwise resulted in the saddle being brought back towards the tailstock not moved towards the chuck; however, after a few ruined jobs, most owners quickly adapted to this idiosyncrasy.
With its top formed into a boring table the "saddle" assembly, could be partially rotated round the bed - which movement had the effect of altering the height of the table in relation to the lathe centres; it was thus possible to make vertical adjustments when setting work on the boring table, making minor adjustments to the height and angle of cutting tools and milling, etc.
A compound slide was never available for the Round Bed, instead the single tool slide was mounted on a vertical bar that passed through an extension to the front edge of the saddle; this extension, being split and formed into a clamp, allowed the toolslide, which had a graduated base, to be both raised, lowered and swivelled. The toolpost was self-contained (which meant that no tool-holding strains were carried by the central bolt) and fitted with a round hole for boring tools as well as the usual rectangular slot.
On the first machines the top of the headstock was machined flat and the bronze bearings bolted to it. On the very earliest lathes these bearings were in two parts, with the upper and lower sections separated by adjustment shims; later models had the bearings formed in one piece with the clearance set by a slot and pinch bolt. Another minor difference of the latter type of headstock was the method of locating the bearing caps--some being found with small studs screwed into the headstock casting and others with locating dowels - it is not known which came first. In 1920 - when the Serial number prefix changed from "MCHA" to "O" - the design underwent some revision and improvements: the left-hand headstock bearing "arm" was increased in size; the bolt-on bronze headstock bearings abandoned and the spindle made to run direct in the cast iron of the headstock with the clearance set by nipping up a clamping screw at the rear. Other changes introduced at the same time (although, as with the flat-bed lathes, there would inevitably have been some considerable overlap) were a reduction in the number of T slots in the cross slide from 4 to 3; a modification to the tailstock where the barrel was increased in diameter and the previous use of a white metal liner abandoned; the adoption of push-in spring retainers on the changewheel studs instead of the previous slow-to-operate, screw-on rings (that tended to come undone when the changewheels were run "in reverse"); the replacement of the detachable changewheel reversing arm by a forward-facing forked bracket cast as part of the headstock - and the very overdue use of a gib strip with adjustment screws on the tool slide..
Although very early examples appear to have had slightly different spindles to later versions with a thread 1.040" in diameter by 14 TPI (with no plain section to act as a register before the abutment face) and bored out to 0.325" rather than 0.375". The spindle was then modified to carry a 7/8"-diameter, 10 TPI thread on the nose and was given a better ground (rather than turned) finish on the bearing surfaces; as standard it was not hollow, but the 0.375" diameter hole could be ordered for a: "small extra cost". Later spindles (fitted to lathes with the headstock spindle running direct in the headstock casting) had a 3/4"-diameter by 10 t.p.i thread with a small plain register about 0.25" long before the abutment face. If your Round Bed differs from these specifications do not be surprised; many have been fitted with replacement spindles over the years and the factory did not seem averse to the occasional experimentation with different details of design. The three-step cone pulley on all models was in cast iron, rather heavily made and with diameters of 6", 4.5" and 3.5" - it was intended to be driven by a 1" wide belt.
From the start of production until 1925 a set of eight changewheels was provided as standard: 20t, 24t, 28t, 32t, 36t, 40t 44t and 64t with an extra set to generate metric pitches (at additional cost) of  25t, 35t, 45t 50t and 63T. Thereafter a set of  9 gears was supplied - which included those necessary for the metric translation: 20t, 25t, 26t, 30t, 35t, 40t, 45t, 50t and 66t giving a threading range of: 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 18, 20, 24, 26, 28, 32, 36 and 40 t.p.i. As on all small Drummond lathes the changewheels were 14 DP with a 14.5 degrees pressure angle; today, unfortunately, the standard pressure angle is 20 degrees so "off-the-shelf" gears will not match satisfactorily; if a new gears are required they have to be specially made. To connect the gears in pairs for a compound train each gear carried a pin and a pin hole; the pins are seated in tapered holes and, if driven out the wrong way, will fracture the gear. By combining extra changewheels a large number of odd pitches and metric threads could also be cut - however, one serious drawback with the lathe was its lack of slow speeds to help with screwcutting and large facing jobs; no backgear was fitted and the bottom speed with the maker's countershaft was approximately 120 r.p.m. To some extent this could be overcome by re-jigging the belt drive to give lower ratios or, more effectively, by resorting to various third-party accessory suppliers who offered two solutions: the ingenious WALRAM unit or some form of backgear. The (very now very rare) Walram bolted in place on the end of the headstock casting (using the reversing stud bracket as one mounting point) and provided a means of gear-driving the headstock spindle either faster or slower than normal or of providing an ultra-fine carriage feed. As it occupied the left-hand threading stud it could, in addition, be used to replace the function of that. The backgears on offer were either conventional designs that bolted on in some way or rather splendid epicyclic mechanisms built into a slightly larger-than-standard and modified headstock pulley. At least two designs of the latter were offered: the first, by George Gentry, being published in the "Model Engineer" magazine during 1912 and the second, by A. E. Bowyer-Lowe complete with illustrations and detailed drawings in the same magazine on April 1st, 1915.  Because the headstock casting assembly of the early lathes lacked the cast-in slot provided on later examples that accepted a stud on which to run an extra changewheel (to produce left-hand threads) the makers offered (at extra cost) a slotted bracket that bolted to the left-hand face of the headstock; this positioned the extra "reversing" changewheel in a rather distinctive fashion above the others. A range of accessories was offered including a vertical slide that, when mounted on a swivelling adapter with a graduated base, could also be used to mount a neat and effective Indexing and Gear-Cutting Attachment. The swivelling adapter must have been either very popular as an accessory, or later supplied as standard, for many used machines come with one in their stock of kit.
A long-bed version of the lathe was also made with production starting late in 1923 - the announcement of its availability being made in January, 1924.
Over the years various drive arrangements were available including the usual type of fixed and fast-and-loose countershafts for wall and ceiling mounting - but the most popular and common fitting was a cast-iron stand fitted with treadle drive and a 100 lb flywheel.
Though of simple construction the Round-bed Drummond was, in sympathetic hands, capable of accurate work and many examples are still in use today. In standard short-bed form its overall length was 2 feet 11 inches (889 mm) and the basic machine weighed approximately 105 lbs. (48 kg).
How many were made? The only evidence of production numbers stems from a comment in a magazine article of 1921 quoting: Fifty of the new type 31/2-in lathes are made each week, and nearly that number of the popular 4-in (Round-bed) model". If the figure of 45 is taken as "nearly that number" - and then rounded down to a weekly average of 35 to allow for slower sales in the early years, during the 1929-1931 depression and approaching the war in 1939 - this would give total of around 56,000.