Collet Chuck, ER-20, R8, Professional Grade 

R8 to ER-20 professional grade collet chuck. Premium 20CrMnTi alloy steel hardened and all ground body for extended tool life. Has a superior finish (electrolysis nickel coating).

The maximum RPM is 8,000 and the maximum runout is 0.0002" (0.0058 mm). The R8 drawbar thread is 7/16"-20.

ER-20 collets have a range of 1/16" to 1/2" (1.0 mm to 13.0 mm).

*Collet must be assembled into a collet chuck nut before inserting into the collet chuck.