Abstract: A surface roughness measuring apparatus (11) has a probe (27, 41) with a smooth surface region (31, 43) contoured to conform to a surface (33) the roughness of which is to be measured, and an aperture (25, 49) located generally centrally of the smooth surface region of the probe. Illustratively, the workpiece surface is a generally flat annular surface portion of a disk brake rotor (35). The test probe surface is juxtaposed with the workpiece surface and a fluid pressure modifying mechanism such as an air vacuum pump (15) and driving motor (17), which are coupled to the probe aperture, are energized to induce a fluid pressure differential between the aperture and peripheral portions of the surface region. A fluid parameter monitoring device such as air flow meter (23) or air pressure meter (19) measures a fluid response to the induced fluid pressure differential and the roughness is inferred from the measured fluid behavior.

Abstract: A process for manufacturing a corner assembly for a vehicle. A wheel hub is partially machined to define a journal section and a radial mounting flange on an out-board surface of the hub. Bolts are pressed into axial openings in the mounting flange and the hub further machining to produce a concentric wheel pilot, rotor pilot and bearing journal surfaces that are perpendicular to radial faces on an out-board surface of the mounting flange. The hub is pressed into a bearing retained of a support member and a rotor is placed on the rotor pilot surface such that the bolts extend through openings located on the inner peripheral surface of the rotor. The hub is rotated to gage lateral deflection with respect to its axis. If the deflection is less than 0.06 mm, the wheel hub and rotor are accepted for installation on a vehicle and rejected if greater that 0.06 mm.