The adaptation of optical principles to the practical needs of workshop inspection has
given rise to the construction of toolmaker’s microscope and projectors. These
apparatuses incorporate every feature of accuracy and refinement in their design, and
hence they are known as precision inspection apparatuses. Projectors and Toolmaker’s
microscope are made to the highest possible standard and represent high constructive
skill and ingenuity in design. The inspection operation and dimensional measurement
that can be carried out with optical projector are similar to engineering microscope in
many ways. However, there are still differences between these two families of optical
measuring instruments. Microscopes are intended primarily for tool room and gage room
applications and require certain degree of skill in operation. On the other hand,
projectors are basically production-oriented instruments in shop floor by machine tool
operators. Optical projectors are not adaptable to various types of special accessories
designed for microscope. But they provide application advantages in many other respects
in comparison to the capabilities of engineering microscopes.
In this unit, we will discuss the principle of the projection techniques used in various
projectors and toolmaker’s microscope. Few applications of these will also be discussed.
We will also discuss constructional details in brief.