The sharpening itself takes place in the prism by turning the arm of the proxxon micromot bsg 220 drill sharpener the turning motion does not only move the prism back and forth but also on its own axis at the same time this automatically provides the necessary relief adjustable spindle with quick axial adjustment the stone is cleaned by pushing a button easy sharpening of drill bits from 3 to 13mm diameter standard angle of 118