A reproduction of the maker's sales catalogue is available
Believed to have been designed during the early 1920s by one John Wilhelm and manufactured until the 1940s, the Ames Triplex was an attempt to produce a "reasonably priced combination machine" able to perform as a simple lathe, boring machine and a horizontal and vertical miller/driller. The maker's slogan was: Three Machine Tools in One - Occupies One-Third Space - One-Third Cost and indeed the machine was, initially, priced at just $485 in basic form, or around $610 compete on a cast-iron base with chucks, faceplate, machine vice, milling arbor and drill chuck. However, while $600 might sound reasonable now, at this would have bought a Chevy Roadster or three South Bend 9-inch lathes - so the concept of "reasonably priced" must have existed only in the minds of those employed in the marketing department. In later years one example tracked down to a purchase by the American Navy in 1938, cost an astounding $2200, twice the price of a contemporary Bridgeport. Assuming that serial numbers started at 1001 (nothing below 1016 labelled as being by the Triplex Machine Tool Corp. has yet been found) the numbers made must have been relatively small at around 150. Despite what must have been rather slow sales, the makers embarked on a series of minor and not-so-minor modifications including a change from straight spur to helical gears in the speed-change gearbox and from flat to V-belt drive. Several examples of the machine found their to England during World War 2, all presumably allocated to machine and experimental shops involved in critical defense work. It's known that at least one example, possibly more, was installed at the British Tabulating Machine Company (B.T.M.), an organization that undertook the development and manufacture of the 210 massive and ingenious mechanical "Bombe" mechanisms (known internally by the company as the 6/6502 or CANTAB) used at Bletchley Park from 1940 to 1945 as part of the Colossus computer programme that helped to decoded enemy signals. B.T.M. also made an exact copy of the Lorch watchmakers' lathe.
The connection between the maker (it is known to have been made at the Ames' works in Waltham, Mass.) and the name on shown sales literature - Triplex Machinery Corporation of 18 East 41st Street, New York City - is not known, but the latter could have been a specially-established subsidiary set up to market the device. The basis of the machine, which weighed 500 lb, resembled the structure of a radial-arm drill with a heavy, 30" x 16" cast-iron baseplate with three T-slots carrying, at its left-hand end, a large-diameter column. Mounted on the column was an elevating "knee" that, being provided with V and flat ways, acted as a lathe-like "bed". At the right-hand end of the base a detachable bracket was fitted that served both as a bracing support for the knee and a holder for the ground-finish tailstock spindle, one end of which was fitted with a No. Morse taper socket. Sliding on the bed was a saddle, topped by a 5" x 14.5" cross-slide-cum-boring table provided with one T-slot longitudinally and another in traverse. The saddle was propelled by a handwheel, working through bevel gears, to a leadscrew positioned between the bed walls. While the maximum travel of the carriage was 10 inches, and the cross feed of the table a reasonable 6 inches, the vertical adjustment was limited to just 4.75 inches. However, run as a lathe the capacity available (a swing over the bed of 16 inches, over the cross slide 10 inches and 14 inches between centres) was, for so compact a unit, practical enough for most smaller workshop tasks. In order to provide a compact 6-speed drive, a gearbox was built into the top of the arm's left-hand section and driven by a 2-step pulley from a motor mounted at the back of the head. Speeds ranged from a usefully low 90 to reasonably high 1050 r.p.m. To convert the machine into a vertical miller/driller the whole of the head was arranged to rotate through 90° on a "vertically curved" arm, its mass being counterbalanced by a weight, hanging on a chain, within the column. So effective was this design that the operator could unlock and then move the head up and down using just the proverbial "two fingers". In order to provide the required quill movement for drilling and milling. the whole of the S.K.F. taper-roller bearing spindle was arranged to slide in and out, over a distance of 3 inches, by means of rack-and-pinion gearing - the operating handle being either a single lever or, on some versions, a 4-spoke capstan wheel. With the 3-inches of quill travel added to the 4.75 inches of the knee, a very useful amount of vertical travel was provided.
Although proper leadscrew-driven screwcutting by changewheels was not available, the makers took advantage of the sliding headstock spindle to provided a "chase" system of master threads and followers. The arrangement was very simple, with a threaded "master" sleeve fitted over the left-hand end of the main spindle and beneath it, held on the end of a swing-up handle, a matching thread. When the operator engaged the two threads the rotating main spindle was driven forwards and the thread pitch replicated in the workpiece.
In order to clear the base for mounting large jobs, the column alignment key could be withdrawn by a T-shaped handle and the whole unit swung out of the way - although, annoyingly, if the operator had been required to set the amount of turn precisely, he would have been disappointed to find the degree graduations only extending to 45 each side of zero.
Although multi-function machines usually fail because of the inherent compromises in their design - and the slowness in converting from one set-up to another - the Triplex, allowing for its simplicity, must be considered as being more successful than most. It was neat, compact, well made - with roller and bronze bearings and hardened and ground spindles - and easily adjusted from one function to another. The ability to undertake angular milling and drilling was a wonderful bonus. The Simplex is rare; if you have one the writer (and an Australian enthusiast) would be interested to hear about it..