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E-MAIL tony@lathes.co.uk Changewheel Drive Cross Slide Gearbox & Tailstock Other Artisan Little is known of the origins of the Artisan Manufacturing Co, of 839 West Sixth Street, Cincinnati, Ohio, USA but, should the design of their 5-inch centre height lathe illustrated below be a guide, they must have produced some interesting machine tools with unique combinations of seldom-seen features. The lathe, of 24 inches between centres, appears to show a manufacturer revelling in a dichotomistic mixture of simplicity, sophistication, cost cutting and extravagance: a plain apron with a "full-nut" and devoid of any controls; a "barley-sugar" coarse-spiral leadscrew (of 2 t.p.i.) with a combination of a hand-cranked (90-degree drive) bevel box for carriage travel combined with power feed and threads from a full screwcutting gearbox; a large-bore headstock spindle with a rather short mounting thread and (originally) a mixture of flat-belt drive and crude, open gearing yet driven by a countershaft incorporating a clutch; a "double-height" single cross slide devoid of a micrometer dial and driven by an exposed Whitworth-form thread and (mounted on a bolt-together, square-base pyramid shaped cast-iron stand) a very deep-section, flat-topped, V-edged cantilever-form bed with a 16-inch capacity in its gap. Even the tailstock contrived to be different with the casting left open at the rear to expose the sliding spindle; although this left a proportion of the spindle unsupported it did have the distinct advantage of letting the locking clamp pull down on an uninterrupted slot and reduced the chances of a split casting as the unit wore in service. |
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The unusual Artisan lathe. The bed, though massively deep, was formed from relatively thin-walled castings with its narrow cross braces spaced well apart. The stand, in this case formed as an open, squared-based pyramid and carried the countershaft across its two rear legs. |
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The countershaft was fastened across the two rear legs and, unusually for a lathe of this size and era, the system incorporated a cone clutch, built into the pulley driven by the motor. The clutch lever was connected to a rod that passed through the lathe bed and down to a simple toggle mechanism that operated against a spring-loaded plate. One must admire the confidence of the designer that a bed with a 75lb motor bolted directly to its back face would not be distorted. |
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An unusual combinations of features with the open gears devoid of any lubrication system yet with a large bore spindle running in very substantial bearings braced by deep ribs upon which rested a sheet metal cover. Change of speed was effected by sliding the double central gear from side to side. |
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Sometimes found on Capstan (hand-screw) lathes where speed, operator convenience and grouping of controls were important, hand-cranked bevel box drive to the carriage feed must have been an expensive addition to the lathe. The second (bar) lever protruding horizontally from the boss beneath the operating shaft was used to operate a dog clutch to engaged and disengage the power feed from the screwcutting gearbox. |
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To the left of the bevel gears can be seen the dog clutch that engaged and disengaged the drive from the screwcutting gearbox. |
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The leadscrew "nut" was fastened not in the centre of the apron (as on most lathes) but bolted to its left-hand face. It appears that the designer, fearful of bending loads overcoming the rather shallow V-edge ways when turning large diameters in the gap, incorporated a thrust plate on the front face of the bed against which an adjuster nut, screwed through a boss on the front left corner of the apron, could bear. The idea is reminiscent of that used on some Barnes lathes where the top of the carriage-feed rack was used in a similar fashion. E-MAIL tony@lathes.co.uk Changewheel Drive Cross Slide Gearbox & Tailstock Other Artisan |
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