测量大型机床导轨时,为提高测量精度和对垂直、水平两个方向测量,一般用平直仪。国产平直仪的“最大工作距离”都在十米内,人们就认为大干十米的长导轨不能用国产平直仪一次调整测完。事实上国产平直仪能测量十米以上长导轨。关键是国产平直仪的“最大工作距离”的含义及测量范 Measurement of large machine tool rails, in order to improve the measurement accuracy and vertical and horizontal measurements in both directions, the general use of the collimator. Domestic flatness instrument “maximum working distance” are within ten meters, people think that the long axis of the dry ten meters can not be adjusted with a domestic flatness finisher. In fact, domestic flatness gauge can measure longer than 10 meters long rail. The key is the meaning of the “maximum working distance” of domestic flatness meters and the measuring range