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Marketed by the Lempco Company of Bedford, Ohio, once well known in the USA for their replacement automobile axles and many varieties of specialised garage equipment (and now a manufacturer of precision products for the metal-stamping industry) the backgeared and screwcutting Lempco Model S 11-inch swing (5.5-inch centre height) was just a lightly modified lathe from the Sheldon range of the 1930s and 1940s. Lempco must have agreed to take a reasonable number of units for both the apron and flat-and-V-way bed carried Lempco's company's name engraved not on a detachable plate but as bold, cast-in letters.
Two bed lengths were available: 44" and 56" that gave, respectively, capacities of 24" and 36" between centres; the lathe could be supplied for bench mounting (Sheldon Model GBM-24/36) - with simple one-bolt feet that would not have looked out of place on a lathe made forty years before - or on a pair of cast-iron legs (Sheldon GFM-24/36). The integral countershaft and 1/4 hp 1725 rpm Westinghouse motor was carried by a tall casting formed as part of the headstock backgear guard with a V belt from motor to countershaft and a flat-belt drive to the spindle. Fitted with cast-iron belt guarding, the assembly was somewhat improved in comparison with that fitted to the Sheldon-badged version: the V-belt drive from motor to top shaft was fully guarded (no guard of any kind appears to have been listed by Sheldon) and the cover above the top 3-step flat-belt pulley came down to its centre line instead of stopping some way short as on the original machine. A quick-release handle, working a cam, slackened the 1.25-inch wide belt for speed changes and incorporated a screwed adjuster to set the tension. The size of the standard electric motor was kept deliberately small so that the machine could be "run from a light socket": a good marketing ploy, but one that would have limited the lathe to lighter work only. However, even the genuine Sheldon version was offered with only a 1/3 hp motor - today, that sort of power would barely spin an egg whisk: a case of they don't make 'em like they used to. The motor's switch was built neatly onto the front face of the headstock and (thankfully) incorporated a thermal overload cut-out. The 1.125-inch bore carbon-steel spindle with its 1.75" x 12 t.p.i. threaded nose ran in bronze bearings (19/16" diameter by 2.5" long at the front and 13/8" diameter by 2" long at the rear) and carried a 6 : 1 reduction backgear on an eccentric shaft; the spindle end thrust was taken by a ball race.
Drive from the headstock to 8 t.p.i., acme-threaded, 3/4-inch diameter leadscrew was by changewheels, the drive passing through a spring-plunger-located tumble-reverse mechanism and then to a simple gearbox that gave 3 sliding speeds, or 3 threads, for each setting of the gears; the thread range stretching from 4 to 80 t.p.i. The gears were guarded by a cast-iron cover (in the rather perfunctory manner, common at the time) with sufficient finger-enticing gaps to cause today's Health and Safety official to collapse on the floor - although if she'd spotted the spindle catchplate with its four open slots (which really was dangerous) she'd have needed a week off and months of counselling to recover. The finest carriage feed that could be obtained with the supplied changewheels was 0.0025" per revolution of the spindle - with the other two rates (using the same changewheel set-up through the 3-speed gearbox) being doubled and doubled again at 0.005" and 0.10"
With zeroing micrometer dials, the compound slide rest assembly had a rather small, two-handle cross-feed handwheel while the knurled-edged, top-slide handwheel lacking any handle at all. The arrangement of the compound slide rest was unusual: the 11.75-inch long saddle was very thick, yet without T slots, and the cross-slide ways sunk below its top surface; the top slide was able to be swivelled through 360 degrees but this facility was bought at the expense of a component that was not only too thick but with a clamping arrangement that meant a good proportion of the horizontal ways on the lower section of the slide had to be cut away in order to give access to the clamping bolt heads. This design was changed on later (Sheldon) lathes with the gib-strip adjustment screws moved to the lower casting and the cut-away in the ways completely removed.
With a 1.25-inch diameter No. 2 Morse taper spindle, the tailstock spindle was locked by a proper compression fitting with the upper section of the body adjustable sideways on its base to allow for simple taper turning. Unfortunately a loose, self-hiding spanner had to be used on the bed-clamp bolt - a cheeseparing move by the maker that would provide a succession of users with the chance to waste the boss's time looking for it..
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