Pro R8 ER-20 Collect Chuck with Drawbar End ~ Made of 20CrMnTi alloy steel ~ Electrolysis nickel coating ~ Premium hardened & all ground body for extended tool life.~ Thread of Drawbar End: R8- 7/16" -20 ~ Maximum RPM is 8,000 ~ T.I.R. <= .0002" ~ Superior Finish.
Thread of Drawbar End: R8- 7/16" -20!
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