Abstract: A cranial perforator includes a generally cylindrical driver, a generally cylindrical drill member and a generally cylindrical sleeve therebetween. The driver is connected to the proximal end of the sleeve. The drill member is connected to the distal end of the sleeve. The sleeve has an internal clutch mechanism to selectively transfer rotational movement from the driver to the drill member. The drill member has an inner drill and an outer drill disposed about the inner drill. The inner drill has a distal end that has only two drilling flutes. A proximal end of the outer drill has a first predetermined diameter D1. A distal end of the outer drill has a second predetermined diameter D2, with the first predetermined diameter D1 being greater than the second predetermined diameter D2. A transition from the first predetermined diameter D1 to the second predetermined diameter D2 is a smooth, preferably radiused curve.