The invention is directed to a method for determining the weight of a probe of a coordinate measuring machine wherein the probe is connected to a probe head of the machine. The side wall defines a generally circular cross-section of the cell as taken along a plane extending perpendicular to the axis, wherein the generally circular cross-section of the sample cell has an average radius. The locking assembly further includes an elongate retention bracket having a channel in which the outer locking portion is received, and a pair of retention portions extending laterally relative to the length of the retention bracket, the outer locking portion adapted to be secured to the retention bracket within the channel. In an alternative embodiment, an anchor is provided on the distal tip for engagement with the far cortex of the bone. Furthermore, the steam may be used for cleaning the pumping means. In one embodiment, a chip stack is sandwiched between first and second redistribution substrates.