Pro-Series High Accuracy ER-20 3/8" Spring Collet (3901-5188)
Superior finish.
AA Grade.
5 Micron.
Runout is less than or equal to .0002".
Made of high grade SUJ2 steel.
Hardened and precision ground to 44-48HRC.
Exceeds Federal Specifications.
Major diameter is .830".
Overall length is 1.230".
Inside diameter is ground to reach mirror finish increasing grip force.
Surface treated to reduce rust and improve hardness.
Cryogenic treatment to significantly increase wear resistance.
Collet must be assembled into collet chuck nut before inserting into the collet chuck.
Shipping Weight: 0.2 lbs
Many metalworking products contain metals that are included in
the latest Prop 65 warning. Exposure to the elements can be
harmful. May cause cancer and reproductive harm.
