Paper 39: In Situ Out-of-Roundness Measurement

Abstract

A new method is described for measurement of out-of-roundness characteristics of parts under conditions that are now considered extremely difficult or impossible.

For example, it is now possible to measure very large parts while they are still mounted in the machine tool, on a makeshift inspection fixture, or even in an assembly. Typical of parts now being measured by this method are crankshaft journals and throw surfaces, piston pins, machine tool spindle shafts, mill rolls, and reactor fuel rods. No expensive masters, precision spindles, or special skills are required. Results are plotted and measured on polar charts such as used on the more conventional roundness gauge. Accuracy of the out-of-roundness measurement is within ±10 per cent for most parts.