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200 Series Apart from one or two design features (and the late-model aprons on Mk. 3a 100 Series machines) the 200 lathes had, almost nothing in common with the 100 Series, being a new design, of greater capacity based on an entirely fresh set of much heavier and more rigid castings. Paul Clausing has started work on what was described in internal literature as the "1-inch collet capacity lathe" in January 1941, but the pressures of war-time production delayed further work until the conflict was over and the first lathe was not ready for shipment until March 31, 1949. Besides its greater capacity, the most radical change centred on the drive system; all the spindle-speed changes were made before the drive belt reached an 'overhung' pulley on the left-hand side of the headstock spindle. This system - of a pulley on the left-hand end of the headstock - had been used before, but only, I believe, on various light-duty wood and wood-cum-metal lathes and to commit such a design to production on a mainstream, medium-duty centre lathe was a bold move. In the event the designer's courage paid off, and countless other makers - Emco, Myford 254, Scintilla, Wabeco, etc. - successfully copied or adapted the principle. As an aside it is interesting to consider the extraordinary lengths that some makers of small lathes went to over the years in order to provide a finely-engineered, mid-headstock bearing pulley system - when they could have achieved comparable results with a much simpler and cheaper (though some would argue aesthetically inferior) overhung system. The swing over the bed of the 200 Series was a true 12.75 inches, over the saddle wings 12.25 inches and over the cross slide 7.5 inches; three bed lengths were available giving 24, 36 and 48 inches between centres. Forged, hardened and ground headstock the spindle had a generous 13/8" bore and 1-inch collet capacity, ran on Timken taper-roller bearings and was fitted with the excellent 'long taper-key drive' nose in an L-00 size fitting that gave both a very rigid assembly and absolute security when running in reverse; the taper bore was finish ground in place after being mounted in its own bearings. Because the headstock spindle was now driven by either one or two V belts from its extreme left-hand end, the headstock could be made in the form of a rigid, open-top box and lubricated from an oil sump within its base - ensuring that the backgears and leadscrew reversing mechanism had a much better chance of survival than before - especially when used for extended periods. Backgear could be selected almost instantly by pulling on a large handwheel fastened to the end of the spindle and throwing over one lever positioned towards the top left of the headstock face. Continued below:
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