FETCOI 4PCS BT40 ER20 Collet Chuck 2.75 Hardened Alloy Steel Black Oxide Mill Holder for Engraving Machine Milling Lathe

Features: Alloy steel hardened to 50-52 rc Critical surfaces precision ground Works on all BT40 machines Collet chuck accepts all ER20 collets Coolant flows through tool holder 70mm Gage Length Hex Nut (included) Balanced to 25 000 RPM at G2.5 0.0001 runout from taper to pocket Taper ground to AT3 standard Specifications Taper: BT40 Collet Series: ER20 Gage Length: 2.75 /70mm Max speed: G2.5@20000RPM Material: Steel Finish: Black Oxide Material: Hardened Alloy Steel ear Thread: M16X2 Concentricity/runout less than: 0.0001 /0.003mm Packages 4Pcs BT40 ER20 COLLET CHUCK