By the late 1930s and like Cataract, their long-time rivals in the precision bench lathe business, Ames were forced to utilise their 40 years of experience in making lathes and millers (and shapers, slotters, automatic gear cutters, micrometer dial gauges and other precision products) to modern their machines. Out went cumbersome and expensive overhead countershafts with their flapping, exposed belts and in came neat, self-contained stands with V-belt drive, speed-change gearboxes and even mechanical variable-speed drive systems. Because of their customers' investment in tooling and accessories it was impossible to make changes to the size or shape of the bed but the headstock of both makers lathes was a prime candidate for modification and, with the advent of super-precision ball races (called at the time "anti-friction" bearings) it was not long before these were being offered in place of the high-class plain bearings that had been in use since the 1880s.
Ames first modified the No. 3 lathe to accept ball races in the headstock but left the rest of the lathe, including the flat-belt pulleys, large unmodified, although it was offered on a rather more compact, self-contained stand,  The next development of the lathe, the 43/8" centre height by 171/2" between centres EH3, was to be its final evolutionary form and, although the bed again remained unchanged, the headstock was completely re-designed and strengthened. Completely enclosed, the 1"-bore, hardened and  ground alloy steel spindle accepted 5C collets (or ones specially ordered to a customer's choice)  and ran in the same type of high precision, pre-loaded, grease-packed ball races as before. The final dive was usually by twin V belts, that could only pass up through the base of the headstock, so forcing the lathe to be mounted on an under-drive stand.  The makers claimed that, for all its precision and great accuracy, it was possible to dismantle and reassemble the headstock (to change the belts) in only "a few minutes." From around 1957 Ames lathes were dual branded with Stark and, designed as integrated units, at least three stands were available: all used a simple mechanical expanding and contracting variable-speed drive arrangement (often by Worthington) with the two intended for industrial use fabricated from braced and welded sheet steel. Both had built-in switchgear, a light unit and collet storage - with one (possibly the earlier) having the speed-control handwheel (it worked through a flexible wire drive) positioned inconveniently towards the rear of the headstock but the other with it mounted in a rather better position on the stand's front face. The third type was a more traditional version, intended for use in an experimental department; it stood on heavy section, pressed-steel legs with a linoleum covered, wooden top edged with strips of polished maple. Standing 36" high it was 54" long, 30" deep and included a metal-faced collet and chuck board built into the right-hand top corner of its top surface together with a light unit mounted behind the headstock on the left-hand side. Unsurprisingly (judging by the numbers surviving) rather than wrestle with the complexities of building their own under-slung, multi-speed V-belt drive countershaft,  most customers chose to buy the lathe on the ready-to-run stand..