puur tsentriavade moodutamiseks enne puurimist või toorikute tsentrite vahele paigutamiseks treipingis või ümarlihvingis (vt tsentripuurimine)
a drill in which a short parallel portion leads to a coned section with an included angle of 60o; used (1) to give accurate start to a twist drill, or (2) to provide a conical recess to ends of workpieces to be machined between centres in a lathe or cylindrical grinder (see: centre drilling/center drilling)
