To find the concentricity of the coupling, the coupling has a circumferential surface and an end surface. 1. On the circumferential surface (radial), the dial indicator can be attached to one end of a coupling. Any position is ok, and no other things can be touched after one rotation; then put the thimble of the dial indicator on the other side of the coupling The reading of the meter should be an integer of about 3—5mm, and the meter can be adjusted to an integer. 2. Make a mark on the upper, lower, left and right of the coupling, turn the dial indicator to these four positions and write down the readings, and then adjust according to the readings. For example, the upper reading is 3mm and the lower reading is 3.5mm. , Then the coupling on one side with a large reading can be raised or lowered on the other side.To be applied flexibly, if it is a motor, it must be raised or lowered.End face——Suck the dial indicator on one end of a coupling, any position is ok, one rotation can not touch other things; then put the thimble of the dial indicator on the end face of the other coupling (also The side of the coupling), the reading of the meter should be an integer of about 3-5mm, and the meter can be adjusted to an integer.The adjustment method is the same as above.The dial indicator of the end face and the dial indicator of the circumference are generally staggered by 90 degrees, and the circumference and end faces are adjusted at the same time, so that they will not interfere with each other.The size of the coupling reading should be calculated according to the support point.

　　The radial direction is the direction of the diameter. For example, for a shaft, the outer circle direction is the radial direction.The axial direction is the direction of the two ends of the shaft.The so-called runout is the deviation value between the actual size and the basic size.For example, if you want the outer diameter of the shaft to be 50mm, the actual measured value is 50.01 or 50.6, etc. The value of this value is more or less than the basic size is the value of the runout.The runout has a reference and belongs to the position tolerance.The radial direction is generally based on the line.