In this post, you’ll learn what is Vernier depth gauge and It’s working, parts, types, least count and errors.
Vernier Depth Gauge
Vernier depth gauge is used for measuring the depth of holes, recesses and distances from a plane surface to a projection. Here the graduated scale is slide through the base and vernier scale remains fixed.
Running through the depth gauge body is the main scale the end of which provides the datum surface from which measurements are taken.
The depth gauge is made precisely so that the beam is perpendicular to the base in both directions. The end of the beam is square and flat like the end of the steel rule and the base is flat and true, free from curves or waviness.
It has the advantage of having a large measuring range without having to resort to the use of extension rods as compared to depth micrometer.
Parts of Vernier Depth Gauge
Following are the different parts of vernier depth gauge:
- Main scale
- Vernier scale
- Locking screw
- Fine adjustment screw
- Movable head
- Measuring face
Types of Vernier Depth Gauge
Following are the two different types of depth gauge:
- Analog type
- Digital type
Least Count of Depth Gauge
Following are the least count of depth gauge:
- The least count of analog depth gauge is 0.02 mm
- The least count of digital type depth gauge is 0.01 mm
Errors in Using the Depth Gauge
The most common errors are listed below:
- Gauge is imperceptibly tipped.
- The base is liſted when a measured point is slid with pressure.
- Point pressure carts the base a trifle.
The above situations are shown in the figure below:
Steps for Using Depth Gauge
- Thoroughly clean and inspect the attachment.
- Fasten it to the movable jaw.
- Set the depth gauge rod with its end in contact with the surface plate.
- Write down the reading, do not depend on memory.
- Raise the movable jaw to clear the obstruction on the part.
- Place height gauge in position and lower movable jaw until rod of the depth gauge contacts the measured point of the part feature.
- Note the reading. The difference between this reading and the reading in step 4 is the height of the measured point above the reference surface.
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