I just put em in the drill press, run a file over them until the size is right, then a few different grits of paper, polish on the wheel, SS the right size, easy. Although for the 3 that hold the Field Coil in I prefer to use allen heads but I grind the heads down so they don't stick out proud of the cover and polish as before, you can get a much better torque on them to hold in the Field Coil without banging into the cover with an impact driver.