Safety lathe chuck for long bars - has collet gauge checking for rigid grip on last portion of barstock during machining

摘要

The lathe has a headstock with a bore for bar feed. The chuck (1) attached to the headstock has radially sliding jaws (2) with an attachment (3) with a semicircular collet (5). When the last portion of the bar (10) is about to be machined it is pulled forwards by about 5 m.m. to check if the bar is still gripped by the sharp end (7) of the collet. If this is the case the bar is pushed back and the machining carried out without any risk of the bar falling out of the chuck.