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Home Machine Tool Archive Machine-tools for Sale & Wanted Parts Home Page Stuck Chuck Countershafts, Jackshafts & Spindle Speeds Oiling of how a lathe and associated equipment functions |
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For many years chucks, faceplates and catchplates were simply screwed onto the end of the lathe's spindle; a bewildering variety of types and sizes of thread were used and non were standardised between manufactures. Although cheap to manufacture and perfectly adequate for most purposes, especially amateur use, threads do have serious limitations centred around safety, rigidity and ease of removal and replacement. To take just one example: a threaded fitting cannot safely be run backwards and, whilst a chuck might happily stay in place as a lathe accelerates up to top speed in reverse, once there it cannot be so easily stopped. Legion are the number of serious accidents caused where an operator has stated a lathe in reverse, realised his mistake, and then (without thinking) applied the spindle brake. Once the chuck starts to unscrew the workman can do nothing but watch in horror as the 200 lb mass, rotating at 800 rpm, accelerates down the length of the workshop smashing machines and people unfortunate enough to be in its way. |
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