测量内螺纹中径常用的方法是在卧式测长仪上,用专用的测量钩,装上球测头进行比较测量。这种测量方法在对零时,球测头与V型块规的V型槽接触,而测量时,球测头则与螺纹曲面的螺旋槽接触。两种接触状态是不一样的,因此,就产生了一定的原理误差。下面对该项误差进行定量的分析。 Common method of measuring the internal diameter of the thread is in the horizontal length measuring instrument, with a dedicated measuring hook, fitted with a ball probe for comparative measurements. This measurement method is zero, the ball probe and the V-shaped block V-groove contact, and measurement, the ball probe is in contact with the spiral groove spiral groove. The two contact states are not the same, so there is a certain principle error. The following quantitative analysis of the error.