A toolmakers microscope is used to measure objects up to 1/100th of a millimeter. It works on the principle of a screw gauge but with additional features to improve ease of use. The toolmakers microscope has a robust base and column with a track to carry the lens and illuminating source. An object is placed on a glass table with scales to measure movement in the X, Y, and rotational directions. Differences in the micrometer readings after positioning the object indicate the length and breadth which allows for precise measurements of tools and threaded components.

1. TOOL MAKERS
MICROSCOPE

2. Introduction
• A toolmakers microscope is a measuring devise that can be
used to measure up to 1/100th of an mm.
• It works on the principle of a screw gauge, but a few changes
were added to it to make its operation more easier.
• It need application of optics too.
• A light focuses on the object and through lens we can see the
shadow of the object, which resembles the object.
• More clear shadow would be enhance the accuracy of
measurement.

3. Construction

4. Construction:
• TMM (toolmakers microscope) has got a robust and
strong base such that it can bear and withstand sudden
loads.
• A column with a track is present to carry lens, along
with illuminating source in certain TMM’s.
• Lens has two perpendicular straight lines marked that
act as reference lines.
• Object to be measured is placed on glass table.
• Glass table is provided with 3 scales on it

5. • Two scales are meant for measuring in X and Y directions and
the movement of table the respective direction.
• The other scale is meant for measuring rotation as well as
rotation of table.

6. Working:
• Object to be measured is placed on
glass table, illuminator is turned on.
• Let the object be a rectangle.
• It may look as shown through lens

7. Using the micrometer heads get it to a points as shown
Note down both micrometer readings

8. • Now turning micrometer heads we can get positions as shown above.
• After setting 2 nd position note down micrometer reading meant for X
movement.
• After setting 3 rd position note down micrometer reading meant for Y
movement.

9. Result:
• Difference in micrometre reading of X movement
gives us the length of the rectangle
• Similarly, the difference in micro-meter reading of Y
movement gives us the breadth of the rectangle

10. Applications:
• Length measurement in Cartesian and polar co-ordinates.
• Angle measurements of tools; threading tools punches and
gauges, templates etc.
• Thread measurements i.e., profile major and minor
diameters, height of lead, thread
• angle, profile position with respect to the thread axis the
shape of thread. (rounding, flattering, straightness of flanks)
• Comparison between centres and drawn patterns and
drawing of projected profiles.