A portable coordinate measurement machine comprising: a manually-positionable articulated arm having first and second ends, the articulated arm including a plurality of arm segments (8, 9) and a plurality of rotary joints (12, 14, 16, 18, 20, 22, 24), the first end including a connector configured to connect to a measurement probe and the second end including a base; wherein at least one of the rotary joints includes: first and second bearings (32, 34); a shaft that engages an inner diameter of the first bearing and an inner diameter of the second bearing, the shaft configured to rotate about an axis of rotation of the first bearing and the second bearing; a housing having at least one port that engages at least one of an outer diameter of the first bearing and an outer diameter of the second bearing; and at least one transducer configured to output an angle signal corresponding to an angle of rotation of the shaft relative to the housing about the axis of rotation, wherein the shaft has two ends (50a, 50c), the two ends (50a, 50c) including a first end that engages the inner diameter of the first bearing and a second end that engages the inner diameter of the second bearing, wherein the two ends are concentric to within one tenth of a thousandth of an inch (0.0001") (2.54μm). a manually-positionable articulated arm having first and second ends, the articulated arm including a plurality of arm segments (8, 9) and a plurality of rotary joints (12, 14, 16, 18, 20, 22, 24), the first end including a connector configured to connect to a measurement probe and the second end including a base; wherein at least one of the rotary joints includes: first and second bearings (32, 34); a shaft that engages an inner diameter of the first bearing and an inner diameter of the second bearing, the shaft configured to rotate about an axis of rotation of the first bearing and the second bearing; a housing having at least one port that engages at least one of an outer diameter of the first bearing and an outer diameter of the second bearing; and at least one transducer configured to output an angle signal corresponding to an angle of rotation of the shaft relative to the housing about the axis of rotation, wherein the shaft has two ends (50a, 50c), the two ends (50a, 50c) including a first end that engages the inner diameter of the first bearing and a second end that engages the inner diameter of the second bearing, wherein the two ends are concentric to within one tenth of a thousandth of an inch (0.0001") (2.54μm). first and second bearings (32, 34); a shaft that engages an inner diameter of the first bearing and an inner diameter of the second bearing, the shaft configured to rotate about an axis of rotation of the first bearing and the second bearing; a housing having at least one port that engages at least one of an outer diameter of the first bearing and an outer diameter of the second bearing; and at least one transducer configured to output an angle signal corresponding to an angle of rotation of the shaft relative to the housing about the axis of rotation, wherein the shaft has two ends (50a, 50c), the two ends (50a, 50c) including a first end that engages the inner diameter of the first bearing and a second end that engages the inner diameter of the second bearing, wherein the two ends are concentric to within one tenth of a thousandth of an inch (0.0001") (2.54μm).