After twenty-three years of steady development the Drummond M-Type reached its final form in late 1924 - a design that was to continue unchanged until the late 1940s. Improvements included a leadscrew half-nut - a rather awkward assembly formed from a substantial bronze "swinging arm" located by a spring-loaded plunger on the left-side of the apron face. The nut (being of the "half" type and likely to be pushed out of engagement) was assisted by an upper thrust pad - a plain, half-round bronze unit retained by a massive bronze nut against the inside face of the apron. The carriage was fitted with a direct (though unfortunately high-geared) rack-and-pinion feed as originally fitted to the power-cross feed BS model. The top slide was thickened towards the rear, where it supported the feed-screw cross plate, and an enormous improvement made by incorporating, as standard, a quick-set toolholder of the "Norman Patent" type. The "Norman" was a simple but highly effective design and consisted of nothing more than a split, hardened steel block, with a broached square tool hole, arranged to slide up and down and clamp to a 1.25" diameter pillar cast integral with the upper section of the top slide. The cast-in post was also  tapped down its centre for two purposes: originally to retain the maker's (very rare) milling slide and, later, to provide a means of clamping down a 4-way toolpost, an item not introduced until the 1930s along with a number of other items long missing from Drummond's meagre accessories list. Around the same time a long-bed version of the lathe was introduced - and also made available to the armed services in a now seldom-seen BS power-cross-feed version. Although further very minor modifications were made, this was the essentially the form in which the lathe continued until the early years of WW2. It was during this conflict, in 1941, when an agency of the Ministry of  Supply, the Machine Tool Control Board (a body responsible for all the Nation's engineering production), decided that Drummond should concentrate on production of their "Maximat" multi-tool lathe (introduced in 1935) and require Myfords to take over manufacture of the "M-Type", a long-established design that had been adopted some years before as the standard model for the Armed Services. One might question why Myford were not allowed to sell their own lathes into this market but, unfortunately, their contemporary models, the ML1, 2, 3 and 4, were completely unsuitable for professional work and, with all machine-tool production allocated to approved industrial users, there was (at least in theory and temporarily) no private market for Myford. Hence, with some spare production capacity and the necessary expertise, Myford were the logical choice to build the Drummond. However, in addition to their new responsibilities, production of the ML2 and ML4 also continued together with a newly-introduced model, the so-called "4-inch Precision" - of which around 400 examples were made. They also found time to design and manufacture several small capstan lathes, loosely based on the ML2 and ML4, as well as other production lathes with beds and headstocks of an entirely different design. The Drummond was allocated a "J" prefix by Myford - (other designations used by the factory included the ML.5 Capstan lathe as "F", the M.U. capstan as the "G", the M.L.6 capstan as "H" and the M.L. 7 as "K").
One can imagine the situation at Myford's Beeston works as the first trucks arrived from Surrey carrying the Drummond equipment including castings, machined and part-machined parts, patterns, drawings, jig, fixtures and tooling. There can be little doubt that, under the pressure of war-time schedules - and with a suitable Myford badge unavailable - the first machines to be built would have been sold with Drummond markings including the maker's plate and its essential screwcutting chart (Drummond's record of serial numbers ran to the 18th of May, 1943). Certainly, several of  the M-Types to pass through the writer's hands that may have been of this type; they were fitted with flat-belt drive, equipped with old-fashioned, wall-mounted countershafts, had exposed changewheels and were somehow "different", with some nuts chemically blacked, a rather better paint finish and subtle changes to knurling and turning marks. Other alterations quickly followed, including the use of metal instead of horn handles for the carriage and leadscrew handwheels and, more significantly, a change from a 3-step cone (flat) pulley drive on the headstock to a 3-step V-belt. One serious drawback to the original Drummond M-Type was that neither a modern self-contained stand nor any form of integrated drive system had ever been developed for it - and the changewheels were still dangerously exposed. In this respect the lathe was hopelessly old-fashioned, and nearly 10 years behind American machines like the Atlas 9 and 10-inch and South Bend "9-inch Workshop" lathes, all of which had either built-on multi-speed countershafts, the availability of underdrive stands or neat bench-mounted drive systems - and safe enclosures for gears and belts. In order to update the Drummond, and turn it into something that could be plugged in and used immediately, or mounted on  bench with the minimum of trouble, several important modifications were made: the headstock pulley system was converted to run an "A"-section V-belt, two-step pulleys were fitted to the motor/countershaft drive and the changewheels fully enclosed with an inner pressed-steel guard and a heavy cast-iron outer cover. It was offered with either a neat, bench-countershaft unit, or fitted to a heavy cast-iron stand with a long countershaft unit hinged from the back and fitted (like the bench countershaft) with a powerful over-centre belt-tensioning arrangement. These late M-Types easy to date - the changewheel cover carrying a sheet-brass changewheel chart stamped with the year of manufacture.
One interesting version of the lathe also produced by Myford was the BS power-cross-feed model, a continuation of the design developed by Drummond for use on board naval ships where power feeds would have been essential in a workshop that pitched and corkscrewed in rough seas. Some modified specials were also constructed (probably to a military requirement) and, though rare, do still occasionally still surface.
Although Myfords were very busy from 1946 with their new and very successful ML7, the M Type continued in production until the late 1940s. The last examples, all of which seem to have been long-bed models - and probably built up from unsold spares - were stamped '1951'.
The changewheel set for the M-Type was altered from previous versions the new arrangement (including metric-conversion gears) consisting of: 20t, 30t, 35t, 38t, 40t, 45t, 46t, 50t, 55t, 60t, 65t and 73t.
A Drummond M-Type photographic essay can be seen here.
M-Type Serial Numbers
Introduced in 1921 and further developed in late 1924, the M-Type continued unchanged until production was taken up by Myford in 1941. Some pre-production examples were manufactured during 1919/1920.
1919 - 1920 Serials 1 to 66
1920 -          Serials 67 to 131
1920 - 1922 Serials 132 to 1121
1922 - 1923 Serials 1122 to 1319
1923 - 1925 Serials 1320 to 1649 "A" suffix applied from No. 1405A--but at random
1925 - 1926 Serials 1450 to 1887
1926 - 1927 Serials 1897A to 2226A
1927 - 1929 Serials 2227A to 2685A
1929 - 1931 Serials  2686A to 2949A
1931 - 1933 Serials 2950A to 3345A
1933 - 1935 Serials 3346A to 3675A
1935 - 1937 Serials 3676A to 4071A
1937 - 1939 Serials 4072A to 4203A
1939 - 1941 Serials 4204A to 4401A
1941 - 1942 Serials 4402A to 4467A
1941 - 1942 Serials 4468A to 4592A (Separate page in ledger)
1943 -          Serials 4534A to 4592A
A pattern machine (presumably a sample) was dispatched to Myford on March 25th, 1943 and the final Drummond production M-type sent to the Admiralty on the June 30th of the same year.