Abstract: The drifting machine is mainly used in the steel pipe production line to inspecting such parameters as straightness and roundness，etc. of the product. When working，the drifting gauge is driven by the driving rod via the driving device to move in the inner cavity of the steel pipe to perform the inspection. Due to the dimensional accuracy requirements of the drifting gauge for the effective length and the diameter within the specified range at both ends，regular inspecting and testing of it are needed. Regardless of any dimension out of the tolerance，it must be rejected；In actual operation，the drifting gauge might be scrapped due to eccentric wear. The cause for the eccentric wear of the drifting gauge is analyzed and identified，as a countermeasure，the adjustable supporting and centering device for the drifting mandrel head is introduced so as to get the problem fixed，resulting longer service span of the drifting gauge.