The accuracy of air bearings is almost entirely determined by the accuracy of the guide. To improve the accuracy, the guide will need to have high stiffness, very good flatness and the right surface roughness.
For best results use the following tolerances:
Surface Roughness 16 micro-inch (0.4 micron) RMS or better
Grade A for high precision
Grade AA for ultra precision
OAV manufactures guide surfaces. With state of the art measuring and testing quipment OAV can assure that tolerances are met and that the air bearings get the desired performance on the guide.