Hardinge says its HQC quick-change collet system offers flexibility, fast change-over and long life. The chucks can also accommodate barstock variation and fast feed rates and spindle speeds. The flexible collet head offers parallel gripping with the collet segments running parallel to the stock even when there are variations in the stock size. The collet head has a working range of ±1/64". Parallel clamping minimizes stock “push back” and is said to require less drawbar force than conventional collets.
Because the system requires less drawbar force to adequately grip the bar, it reduces breakage of closing fingers and pins, which is common when the bar varies beyond the range of a standard solid collet or master collet with pads, the company says.
Users can change from one size collet to another in less than 20 seconds via a manual or hydraulic changing wrench that compresses the collet.
The collet heads are designed with replaceable inserts that form a seal while holding the collet segments together. The seals protect the spindle, collet body and draw tube from chips and coolant. The collets are available for multi-spindle automatic screw machines, Hardinge collet-ready CNC lathes and chuck-style lathes.
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