Description: Description 14pcs Spring Collets Set with C20 ER20A 100L Collet Chuck Holder CNC Milling 100mm Extension Rod Straight Shank Collet Specification Model ER20Material Spring SteelPrecision 0 015Gripping Range 1 8 9 64 11 64 5 32 3 16 7 32 15 65 9 32 5 16 11 32 3 8 13 32 7 16 1 2 Upper Diameter 28 mmBottom Diameter 25 mmHeight 34 mmT I R 0 0003 or 5um Suitable For Boring milling drilling tapping engraving CNC spindle machines and other processingGround roughness is Ra0 4 Microns plus overall fine polish Holder Specification Model C20 ER20A 100LMaterial 40 chromium 40CR Hardness HRC46 50Accuracy 0 01Shank Diameter 20mmClamping Range 1 13mmLength 100mm Feature 1 Extension rod diameter and the other parts are precision ground to eliminate imbalances increased stabilityduring cutting tighten the nut directly high rigidity extremely powerful clamping force 2 C20 shank holding all ER20A collets 3 C20 20mm diameter straight extended shank applicable for deep processing 4 Extension rod diameter and other parts have been precision ground to eliminate unbalanc and increase stability during cutting5 The clamping nuts could be tighten straightly high rigidity strong clamping Package Included 14 x ER20 Collets1 x C20 ER20A 100L Chuck holderMore Details