HHIP 8" 6-Jaw Self-Centering Plain Back Lathe Chuck ~ Excellent for holding and machining thin walled workpieces. ~ Made of high grade semi-steel. ~ Self-centering, hardened and precision ground jaws. ~ 1 set of 3 X M10 mounting screws included. ~ Adjusting wrench is supplied. ~ .003" T.I.R. ~ Maximum RPM is 3,000. ~ Internal clamping range is 4.0-85mm (.16-3.35"). ~ External clamping range is 65-200mm (2.56-7.87").