Concentricity test device

A concentricity test device to test concentricity of a pierced round workpiece, the concentricity test device comprising:

• a bracket comprising a first supporting arm, a second supporting arm opposite to the first supporting arm, and a beam connected between tops of the first and second arms;
• a positioning member pivotably connected to the first supporting arm and comprising a shaft extending towards the second supporting arm, wherein the workpiece is to be placed around the shaft;
• an operation member pivotably connected to the second supporting arm and comprising a pole extending towards the shaft, wherein the pole is coaxial with the shaft and to be detachably engaged with the shaft to abut against the workpiece such that the workpiece is tightly placed on the shaft, and when the pole is rotated, the workpiece and the shaft are driven to rotate together with the pole;
• and
• a probe indicator fixed to the beam, and comprising a spring-loaded probe extending towards the workpiece placed on the shaft, and a gauge head connected to a bottom end of the probe to engage with a circumference of the workpiece,
• wherein when the pole is manipulated to rotated 360 degrees, the shaft and the workpiece are rotated 360 degrees together with the pole, values shown by the probe indicator show moving distances of the probe, and a maximal difference value of the moving distances of the probe is the concentricity of the workpiece.