Static Gravity Reference Vector Determination for Sensor Calibration
Static gravity reference determination requires site gravimetric surveying and arcsecond stage indexing to isolate true sensor bias from facility tilt errors.
Bearing Radial Runout
Geometric Deviation
Rotational variance defines the class of form errors that quantify the displacement of a shaft axis during a complete revolution. The term bearing radial runout denotes this deviation from a perfect circle when measured perpendicular to the axis of rotation. It limits the precision of high-speed spindles and rotary sensors.
Measurement Protocol
Metrologists assess this profile by mounting the bearing assembly on a master spindle or between precision centers. High-resolution indicators or non-contact capacitive probes track the outer ring surface as the shaft rotates through a full circle. This process yields a total indicator reading that isolates the eccentricity from the high-frequency roundness errors of the race itself.
Because temperature shifts alter the fit between the housing and the bearing, these tests must occur under stable environmental conditions to avoid drift.
Accuracy Consequence
Excessive deviation causes uneven loading on the rolling elements, which accelerates wear and shortens the operating lifetime of the assembly. This imbalance introduces high-frequency vibrations that degrade the surface finish of machined parts. In optical and sensor systems, it shifts the focal plane or introduces angular errors in encoder readings.
Compensation Strategy
Machinists minimize the effect by matching the high point of shaft eccentricity with the low point of the bearing race. This manual alignment balances out the systematic runout, leaving only the random errors. Precision grinding of the assembled shaft remains the final method to achieve sub-micron tolerances.