The magnet core will be fitted onto the armature shaft. A drill press could be used to drill a hole accurately, but with a little care, a properly aligned hole can be made with a vise and a handheld drill. I centered the dimple from the center punch between the jaws of the vise. Notice the two yellow squares for mentally aligning the drill while boring. Stop and check your progress regularly. Make corrections as needed. I rested the heel of my hand on the top of the vise while drilling to steady the drill in its proper position.