зенковка коническая
süvisti kooniliste pindade süvistamiseks (vt koonussüvistus; vrd silindersüvisti, otssüvisti), a pilot guided end cutting tool used for countersinking, having two or more cutting lips and usually having straight or helical flutes for the passage of chips and the admission of a cutting fluid (see: countersinking; compare: counterbore, spot facing tool)