The test fixture shall consist of a steel test plate or test insert with a hardness of 700 HV30 minimum. The hole of the test plate or test insert to accommodate the mandrel shall be equal to the nominal diameter of the mandrel to be tested with the tolerance ++00,,42 mm. The thickness of the test plate or test insert shall be at least 5 mm but shall be sufficient to hold the test load without showinr plastic deformation.