Hitachi DH 40FB Instruction And Safety Manual page 15

3. Dismounting (Fig. 17)
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.
Core Bit
Shank
Fig. 17
English
15