Sharpens either ¼ inch or ⅛ inch rods. Simply insert the blunt carbon rod into the collet and push button on the side of housing. Rotate collet to produce 1 mm diameter tip in about three to four seconds. To reduce the possibility of tip breakage, stop the motor before withdrawing the sharpened rod. This sharpener produces straight sided tips. To make pencil form rods, use a regular pencil sharpener.