A compact Mode II fracture specimen together with its loading frame is analyzed and tested. This system is a further development of an earlier circular Mode II fracture specimen presented by the authors. For fatigue precracking in two different loading configurations, formulas relating the Mode I stress intensity factor, applied load, and specimen geometry are developed. In order to determine K//I//I//c from the fracture load, a relationship between K//I//I, the applied load, and specimen/loading frame geometry is obtained. All of these relations are calculated by means of the finite element method.