A portable coordinate measurement machine "CMM" 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 (30, 50, 80) 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 (28, 48, 49, 78) having at least one port (48b, 49b, 87) 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 at least one port of the housing has no portion whose diameter is narrower than the outer diameter of the first bearing or the outer diameter of the second bearing and/or the shaft has no portion whose diameter is larger than an inner diameter of the first bearing or an inner diameter of the second bearing; and. wherein a first joint, from the plurality of joints, is attached to a second joint, from the plurality of joints, by a structure that is in contact with the inner or outer race of a bearing of the first joint or the inner or outer race of a bearing of the second joint, the structure fabricated from steel, stainless steel, or a controlled expansion alloy lighter in weight than steel and having a thermal expansion coefficient matching that of steel or stainless steel in the range of between of 9.9 to 18 μm/m°C at 25°C. 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 (30, 50, 80) 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 (28, 48, 49, 78) having at least one port (48b, 49b, 87) 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, first and second bearings (32, 34); a shaft (30, 50, 80) 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 (28, 48, 49, 78) having at least one port (48b, 49b, 87) 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 at least one port of the housing has no portion whose diameter is narrower than the outer diameter of the first bearing or the outer diameter of the second bearing and/or the shaft has no portion whose diameter is larger than an inner diameter of the first bearing or an inner diameter of the second bearing; and.