A skull pin assembly for use with a skull clamp includes a skull pin that is slidable into contact with a head of a patient. A pin load applicator is removably connectable to the skull pin assembly and includes a loading shaft that is able to apply a force against an inner end of the skull pin. The pin load applicator also has a biasing element operable to apply a force on the loading shaft that, in turn, transfers the force to the skull pin. A load force indicator is connected to the loading shaft and provides an indication of the force being applied by the skull pin. The pin load applicator permits the force being applied by the skull pin to be adjusted to a desired value; and thereafter, the pin load applicator is removed from the skull pin assembly without changing the desired skull pin force.