Serial No. 386: a particularly fine (and rare) example of a Stark bench-precision milling machine that was shipped to the Portland Machinery Company in Portland, Oregon on January 7th, 1938. The miller was mounted on the maker's stand and fitted with an integrated 3-speed gearbox drive system incorporating a twin-disc clutch that allowed speeds to be changed with the motor running (but not with the clutch engaged).
The machine has survived complete with its original test cards (displayed below that show the measured run-out of the spindle and its collet location was 0.000"), swivelling vertical head machine vice and light unit.

Rear view of the complete under-bench drive unit showing the supporting frame, motor and coupling and clutched 3-speed gearbox.
Driving a small milling machine was always an awkward engineering exercise - ceiling and wall-mounted drive countershafts made for their lathes did not always adapt well to the problem - and by the early 1930s Stark were offering a neat, self-contained motor drive unit mounted on a substantial cast-iron frame and designed to fit beneath a bench. It was also offered for the Company's lathes and was advertised and marketed as being suitable for other makes as well - it being easily set up to drive any number of small machine tools that would otherwise have required a separate and cumbersome one-off drive units. The assembly consisted of a supporting frame, motor and coupling, 3-speed gearbox with a cultch and a drum-type reversing switch. The speed-change lever could be operated whilst the drive was running and the gearbox, with three shafts, all supported on adjustable Timken roller-bearings, used a series of non-metallic gears engaging with hardened steel gears running on hardened shafts - lubrication being by immersion in an oil bath.