Third angle projection

An excellent perspex model to illustrate Third Angle projection was featured in one of the earliest issues of technical education. At that time a home‐made fixed model of mine, FIGURE 1, was proving to be quite successful in showing to a comparatively small number of students the difference between First and Third Angle projection. Engraving the lines on to the perspex faces of the model before assembly was a tedious operation and, although the advantages of a ‘glass box’ which opened out were fully appreciated, it was clear that a less painstaking way of producing black lines on a clear surface would have to be found. At the back of my mind had been the thought that photographic methods might provide a solution to the problem.