Collet Chcuk Nut Replacement UM Type ER20 Thread is M25 X 1.5
UM-Type ER-20 Collect Chuck Nut
Balanced to 18,000 RPM
Tolerance is .0003″ Maximum
Material is 42 CrMo
Hardness is HRC 50-52
Thread Tolerance Class is 4H-Class
Thread is M25 X 1.5
D is 35 mm
L is 19 mm