One sticking to the drill? (3)
I believe the answer is:
bur
'drill?' is the definition.
(small surgical drill)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for bur that I've seen before include "Clinging seed case" , "Prickly seed case" , "sticker" , "small drill" , "Seed-case" .)