牛头刨床在工作时要求垂直升降刀架严格按传动比下降，以保证每个工件都能得到相同的切削深度。但在实际工作中，刀架往往会突然多下降一段距离。有时甚至丝杆根本未转动，由于震动，刀架也忽然下冲一段距离。这就使刀具突然增加了切削深度，严重时会使刀具断裂、工件报废... Shaper in the work requirements vertical lift turret in strict accordance with the transmission ratio down to ensure that each workpiece can get the same depth of cut. However, in actual work, the tool holder will often suddenly drop some distance. Sometimes even the screw did not turn at all, due to vibration, knife suddenly under a distance. This makes the cutting tool suddenly increase the depth of cut, serious tool breakage, the workpiece scrapped ...