Floating instrument insert for a tool

An instrument insert for a tool of the type comprising an inner member extending within an outer member, the inner and outer members being capable of relative longitudinal movement. The insert includes a first insert portion comprising a first instrument component of an instrument, a second insert portion comprising a second instrument component of the instrument and a coupling mechanism for connecting the first and second insert portions and for maintaining the first and second insert portions in a fixed relative longitudinal position. Further, the first and second insert portions are each adapted to be connected with one of the inner and outer members and the insert is adapted for mounting within the tool at a radial position between the inner and outer members such that the insert is capable of longitudinal movement relative to at least one of the inner and outer members.