Portable coordinate measurement machine having a removable external sensor

A portable articulated arm coordinate measurement machine, comprising:

• a manually positionable articulated arm having opposed first and second ends, the articulated arm including a plurality of connected arm segments, each arm segment including at least one angular encoder configured to produce a signal corresponding to an angle of rotation;
• a base section connected to the second end;
• a measurement probe connected to the first end, the measurement probe configured to receive an externally mounted sensor having a kinematic attachment ring, the measurement probe having surface configured to align the kinematic attachment ring with respect to the measurement probe, the measurement probe including an external threading configured to extend through the kinematic attachment ring;
• a retaining ring having internal threading configured to threadably receive the external threading, the retaining ring further configured to couple the kinematic attachment ring to the inner face;
• and
• an electrical circuit configured to receive the signal and to provide data corresponding to a coordinate of the externally mounted sensor, the data based at least in part on the signal.