Piece of drill? (3)
I believe the answer is:
bit
This clue is a double definition.
'piece' is the first definition.
(synonyms)
'drill?' is the second definition.
(thesaurus)
'of' is the link.
(Other definitions for bit that I've seen before include "Morsel" , "gripped" , "Small fragment" , "something boring" , "Took effect - fragment" .)