将底板调成水平的目的是将中刀承调成水平.为什么要把中刀承调成水平呢?一是:因为中刀承表面比较光滑,如果表面不水平,横梁被升起并以中刀口为支点摇摆的时候,横梁就会向下倾方向移动.从而使天平的示值变动性误差增大.换句话说,天平的平衡位置就不稳定.移动较大时,天平横梁还会与支架发生摩擦.二是:因为天平 The purpose of leveling the bottom plate is to adjust the middle knife into horizontal. Why should the middle knife be adjusted to level? First: because the middle blade bearing surface is relatively smooth, if the surface is not horizontal, the beam is raised and the middle When the knife edge swings as the fulcrum, the beam will move downwards in the direction of tilt. This will increase the variability of the display of the balance. In other words, the equilibrium position of the balance will be unstable. When the movement is large, the balance beam will also Bracket friction occurs. The second is: because the balance