Founded in 1889 by William A. Greaves and Herman H. Klusman the Greaves-Klusman Company was based in Cincinnati, Ohio, the home town of the two owners. Early days were spent in premises on Second Street, near Plum, with early advertising literature stating that their aim was to "... manufacture machine tools and woodworking machinery.". Obviously well capitalised - in their first year of trading over twenty men were employed - by 1898 a move had been made to a new and much larger factory of sixty thousand square feet on Alfred and Cook streets where one hundred and twenty five "skilled mechanics" were employed. By the 1920s the firm appeared to have concentrated production around a range of heavy-duty metal-turning lathes distinguished from their competitors not only by an unusual control mechanism for the selection of headstock-spindle speeds - but through the use of an all-geared headstock arranged along the lines of the sliding-gear transmission used in automobiles. Instead of a separate control for the clutch, in the Greaves-Klusman lathe a single movement of a vertical lever, in or out, engaged or disengaged the clutch while a further movement of the same lever, to the right or left (in plainly-marked notches) instantly selected any of 10 spindle speeds without stopping the lathe - and with the tool still cutting. Self-locking, the selector lever worked in connection with the notched segments and a direct-reading index plate to form a simple control system - the extreme movement from low to high speed occupying an arc of 70 degrees.
All headstock gears were made from chrome-nickel steel, hardened and heat treated - with the bores ground concentric with the pitch circle - and ran on shafts which were hardened and heat-treated. Lubrication was effected by the lower gears splashing oil throughout the box, with an externally-mounted sight-glass  indicator on the front of the headstock to check the level.
Controls to reverse the carriage drive were fitted to the apron, rather than the headstock (an arrangement which was becoming increasingly common on heavier lathes by the 1920s) whilst the headstock spindle could also be stopped, started and reversed from the apron as well.
Spindle speeds were in geometric progression with, it was claimed, the ratio of "direct speeds" to "backgear speeds" arranged so that, after a roughing cut in the latter, the former could be instantly engaged to give the correct speed for finishing cuts.     
Constructed in the form of a box, with internal longitudinal and transverse braces, the headstock had sides that extended up to the center line of the spindle; this formed a rigid assembly as well as an oil and dust-tight reservoir. The headstock spindle was made from high-carbon "crucible" steel, and ran in alloy-bronze "boxes" (an old-fashioned way of describing a particular arrangement of plain-bearing).
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On all the lathes above 18 inches in capacity, both spindle bearings were hardened - but on the smaller machines only the front bearing benefited from this treatment. The headstock bearings had their own oil supply, separate from that within the geared headstock, each being fitted with an adjustable sight-feed 'drip' oiler. The spindle end thrust was absorbed by alternate bronze and hardened-steel thrust collars against the rear of the headstock casting.
Power was fed, via large, flat pulleys into a layshaft - so reducing some of the vibration and stresses before the drive was passed to the mainshaft - whilst he main drive pulley on the headstock was given its own (ball) bearing to prevent belt loads beings transmitted into the drive shaft. The internal headstock gears were arranged so that only those required to drive the spindle were in mesh, all the others remaining idle to reduce frictional losses - a system that was widely used on all types of geared-headstock lathe at that time.  The initial drive shaft transmitted its power to a 'driven shaft' with a cone of five gears. Power was then sent to a second 'driven shaft' having a cone of three sliding gears that engaged with three of the cone gears on the first driven shaft. On one end of the three sliding gears a positive stepped clutch was formed and, by sliding these three cone gears along the shaft, they connected with a spring-tensioned cone of two gears with another positive stepped clutch. When in this position the cone of three gears - and the cone of two gears - were clutched together and gave power to the fourth and fifth cone gears on the second driven shaft. By sliding these five gears further along, the fifth cone gear on the second driven shaft was engaged, thus making five changes of speed direct to the spindle - as well as five changes of speed through the back gear - thus providing a total of ten spindle speeds - all selected one lever. A wonderful arrangement, until it went wrong.
Instead of an ordinary thread backed by short register, the spindle nose had a  register both in front and behind - that at the front acting as a pilot to the chuck or face plate whilst the larger diameter was threaded with a wide shoulder ground accurately at right angles to the smaller diameter. To help customers, the various spindle diameters and threads were standardised on the 16", 18" and 20" lathes - as were those of the 24" and 30" models - thus allowing chucks and face plates to be (economically) interchangeable between the models in each group..

Greaves-Klusman lathe with the headstock spindle removed to show the arrangement of the three shafts, the drive gears and the associated selector mechanism.

Greaves-Klusman lathes had the option of a neatly arranged and very compact drive system - though the use  of a jockey pulley to increase the "wrap-around" of the wide flat belt on the motor pulley would have been useful addition