Noncontact Small-Diameter-Bore Gauge.

Current Peacekeeper and small ICBM guidance systems require measurement tolerances of 5 microinches on bores used in critical bearings in the SFIR Specific Force Integrating Receiver and TGG Third Generation Gyro. A Phase I program investigated the feasibility of developing a noncontact measurement system based on the principLe of optical triangulation for characterizing the diameter and cylindricity of these bores. The study showed that the fundamental limitations to the measurement technique are in sub- microinch range. A first prototype probe was constructed and used to demonstrate the measurement of internal diameters to the resolution limit of the AD converters employed 8 microinches. Once developed, the proposed probe will allow easy measurement of the internal dimensions of cylindrical shapes. This tool would have wide applications as a generic precision measuring tool.