EMM 305: Metrology Third Trimester Examination

Measurement paper for the aerospace degree. Compares mechanical optical and flow type pneumatic comparators with sketches, works the angle dekkor and the set-up used to establish a precise forty-five degree angle on a v-block, and defines the terms used in the numerical assessment of surface finish: centre line average, root mean square and average peak to valley height. Continues with the accuracy requirements of a sine bar and its use for measuring unknown angles on heavier components, the rolling gear testing machine, how the flow type pneumatic comparator detects variation from a datum, the Tomlinson surface meter, and the taper angle of a taper plug gauge. Closes on the advantages of the mechanical optical comparator, the flatness testing interferometer, sources of error when using sine bars, the optical projector and thread pitch measurement, and the tracer type profilogram.