These screws need a jeweler's screwdriver or similar - round Phillips head. Metric dimensions are nominal and specified as Overall Length x Shank Diameter Under Head x Head Diameter. See below for size and gauge code.
Used on high speed bench grinders usually with buffing compounds to polish metal. Sisal mops are the coarsest fibre similar to that in rope and act as a strong and aggressvie carrier for your choice of cutting compound.