Datum surface: The X, Y, Z reference plane must be set at least in the triangle on the base of the vehicle inspection tool. The accuracy of the reference surface must be ground.
The datum coordinate values directly intercept the body coordinate coefficient values.
The verticality of the X- and Y-faces of the reference plane in the length direction and the width direction is: +/-0.05mm/1000mm
The height direction datum plane: the Z-plane of the lower part of the bottom plate, its own flatness must be 0.05mm, and the parallelism with the upper plane of the bottom plate is guaranteed: 0.1mm/1000mm.
Reference hole: In order to process the car inspection tool or use the gage for three-coordinate measurement, it is convenient to accurately fix the gage on the machine table and set the reference hole.
The pitch of the reference holes is a multiple of 200 mm and should fall on the hundred-digit line of the car coordinate system.
The two reference holes should be marked (No. 1 round hole, No. 2 oval hole) and the coordinate values should be marked.
Install the coordinate line nameplate next to the datum and reference holes. See Annex VW 39D725.
The coordinate line is required on the bottom plate of the gage, and the tag of the gage is required to be fixed on the bottom plate.
The reference hole for small gauges can be selected separately.