Hitachi DH 38YE Instructions De Sécurité Et Mode D'emploi page 14

English
3. Dismounting (Fig. 14)
Remove the core bit shank from the rotary
hammer and strike the head of the core bit
shank strongly two or three times with a manual
hammer holding the core bit, then the thread
becomes loose and the core bit can be
removed.
14
Core bit shank
Fig. 14