Sundely ER11 ER16 ER20 Precision Spring Collet Set CNC Milling Lathe Tool UK. ER11(13pcs,1mm-7mm)(1mm,1.5mm,2mm,2.5mm,3mm,3.5mm,4mm,4.5mm,5mm,5.5mm,6mm,6.5mm,7mm). 1, Put the chuck into the pressure cap, gently turn the clamp spring, when eccentric portion of the pressure cap recessed clamp spring groove.
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