众所周知,工件轴线与仪器导轨运动方向不重合将会给测量带来误差。因此,在测量开始之前,都必须把被测工件找正,以消除工件轴线与仪器导轨运动方向不重合产生的误差。但绝对重合是不存在的,多多少少会给测量带来误差。该误差属系统误差,可用二次读数法取平均值消除。但是,在某些情况下,该项误差是不能用二次读数法取平均值来消除的。那 As we all know, the workpiece axis and the direction of the instrument does not coincide with the rail will bring measurement error. Therefore, before the start of the measurement, the measured workpiece must be corrected to eliminate the error caused by the misalignment between the workpiece axis and the guiding direction of the instrument rail. But the absolute coincidence does not exist, more or less will bring errors to the measurement. The error is a systematic error, secondary readings can be used to eliminate the average. However, in some cases, this error can not be eliminated by averaging second readings. that