The vernier height gauge is mainly used in the inspection of parts and layout work. It may be used to measure and mark vertical distances above a reference surface, or an outside caliper.
The vernier height gauges are typically measured on a granite surface plate or to measure the characteristics of apart from a datum plane.
2. Which of the following is incorrect for vernier height gauge?
Both the surfaces of the measuring jaw should be at 45° to the base
These gauges can be used for scribing purposes
Removable clamps are used
Surface plate is used as datum surface for measurements
Answer.1. Both the surfaces of the measuring jaw should be at 45° to the base
Explanation:-
The vernier height gauge is an instrument that consists of a fixed part and another moving part. The fixed part consists of a hardened and grounded ruler. The movable part consists of the cursor on the vernier which slides the ruler.
Measuring jaw and scriber:- The clear projection of the measuring jaw from the edge of the beam should be at least equal to the projection of the beam from the base. For all positions of the slider, the upper and lower gauging surfaces of the measuring jaw should be flat and parallel to the base to within 0.008 mm.
The vernier height gauge is used on a flat surface or tray machine to draw vertical distances and determine the centers. The scribe is made of hardened steel and is mounted on the height gauge.
By replacing the scribes with an indicator, the vernier height gauge becomes a gauge of verification or comparison of the heights of precision.
3. The projection of the scriber beyond the jaw should be at least
30 mm
15 mm
25 mm
20 mm
Answer.3. 25 mm
Explanation:-
The measuring faces of the scriber should be flat and parallel to within 0.005 mm. The projection of the scriber beyond the jaw should be at least 25 mm. Vernier height gauges may also have an offset scriber and the scales on the beam is so positioned that when the scriber is co-planar with the base, the vernier is at zero position.
4. What is the hardness of measuring jaws of vernier height gauge made up of stainless steel?
350 HV
450 HV
550 HV
650 HV
Answer.4. 650 HV
Explanation:-
The underside of the base, faces of the measuring jaw, and scriber are hardened to about 700 HV or 58 RHC for good quality steel and up to 650 HV or 56 RHC for stainless steel.
5. The accuracy of the vernier height gauge is
0.01 mm
0.02 mm
0.04 mm
0.06 mm
Answer.2. 0.02 mm
Explanation:-
Vernier height gauges have a large steel base for stability and a hardened steel column engraved with inch and mm units. The moving slide is engraved with vernier calibrations enabling settings to an accuracy of 0.02 mm and 0.001″. Attached to the moving slide is a wedge-shaped steel scribe that has a pointed tungsten carbide tip. The height of the scribe’s point can be finely adjusted with a thumbscrew.
6. Which of the following option is correct for the given statements about vernier height gauge?
Statement 1: The projection of the scriber beyond the jaw should be 10 mm. Statement 2: Flatness of working surface of scriber can be checked by the knife edge.
Only statement 1 is correct
Only statement 2 is correct
Both the statements are correct
Both the statements are incorrect
Answer.2. Only statement 2 is correct
Explanation:-
The measuring faces of the scriber should be flat and parallel to within 0.005 mm. The projection of the scriber beyond the jaw should be at least 25 mm.
A scriber is a pointed tool used for marking lines on metals. The offset scriber is a vernier height gauge attachment that permits setting heights from the face of the surface plate. When using this attachment, it is not necessary to consider the height of the base or the width of the scriber and clamp.
The flatness of working surfaces of scriber and measuring jaws is checked by knife-edge straight edge or optical flats.
When an optical flat is placed on another surface and illuminated under a monochromatic light source, the light waves reflect off both the bottom surface of the flat and the surface it is resting on.
Straightedge is used for measuring the straightness and flatness of the work surface. A straightedge consists of a length of steel or any other suitable material usually of narrow and deep sections.
The usual shape of the straightedge is rectangular but for precision work, one edge may be formed into a knife edge The narrow edge of the straightedge serves as the working surface whereas the wide edge serves as its base when not in use and this also provides the rigidity to the tool.
7. Varnier height gauge is/are available in the size of
0 to 20 mm
20 to 250 mm
30 to 300 mm
All of the above
Answer.4. All of the above
Explanation:-
Vernier height gauge comes in a variety of sizes. Vernier height gauges are available in sizes of 0 to 20 mm; 20 to 250 mm; 30 to 300 mm; 40 to 500 mm; 60 to 800 mm; and 60 to 1000 mm.
8. What is the standard reference temperature for the measurement of the accuracy of vernier height gauges?
20 K
20° C
40 K
40°C
Answer.2. 20°C
Explanation:-
The accuracy of performance of a vernier height gauge is based upon the quality and precision of the various features, e.g. the accuracy of the dividing of the scales, the quality of the graduation marks, the straightness of the guiding edge, the flatness of the base datum and the measuring faces.
This British Standard specifies requirements for the construction, accuracy at the reference temperature of 20 °C and the protection of metric and imperial precision vernier height gauges which include a scriber for marking heights. The metric height gauges measure height up to a maximum of 1 000 mm using a main scale and vernier scale graduated to read to 0.02 mm.
9. Which of the following option is correct for the given statements about vernier height gauge?
Statement 1: The surface of the vernier and beam should have a dull finish. Statement 2: The beam shall be marked with the unit symbol
Only statement 1 is correct
Only statement 2 is correct
Both the statements are correct
Both the statements are incorrect
Answer.3. Both the statement is correct
Explanation:-
It is recommended that for ease of reading, the surface of the beam and vernier should have a dull finish and the graduated lines should be black.
The beam shall be marked with the unit symbol of the scale figures, i.e. either a) mm or cm, or b) in.
10. When the scriber is coplanar with the base the vernier is at _____ position?
Middle
1/4th
3/4th
Zero
Answer.4. Zero
Explanation
Vernier height gauges may also have an offset scriber and the scales on the beam are so positioned that when the scriber is co-planar with the base, the vernier is at zero position. Provision shall be made for re-setting the zero position.
11. Which of the following protective measure should we take while using Varnier Height Gauge?
Use Spring Jaw
Should be Kept in an open place
Avoid cold hand
Should be kept in case
Answer.4. Should be kept in the case
Precaution while using vernier height gauge
When using any height gauge care must be taken to ensure that the base is clean and free from burrs. It is essential, too, that the final setting of vernier height gauges be made after the slider has been locked to the vertical column.
The height gauges are generally kept in their cases when not in use.
Every care should be taken, particularly in the case of long height gauges, to avoid its heating by warmth from, the hands.
The springing of measuring jaw should be always avoided.
12. The main advantage of the vernier height gauge is
High precision
Cheap
Can be used for internal and external measurement
All of the above
Answer.4. All of the above
Explanation:-
The main advantage of using a vernier height gauge is:
Vernier height gauge is a special type of vernier instrument which is used to measure the heights of different by high precision and accuracy during many industrial jobs where the measuring process is required. It includes accessories that increase its usefulness. The depth device, scribes made of tungsten carbide, out-of-track scribes, and the buttons of the toolmaker help in the precise identification of a bore.
One set of jaws can be used to determine internal measurements, while another set can be used to measure external measurements.
It is the simplest and quickest to use and is also quite inexpensive.
13. The main disadvantage of vernier height gauge is/are
Highly expensive
Required skill operator
Low precision
All of the above
Answer.2. Required skill operator
Explanation:-
The main disadvantage of the vernier height gauge is that It can be used to measure only small objects. The vernier height gauge readings are highly dependent on the ability of the operators, and its accuracy is limited by the Vernier scale.
14. Which of the following is the application of a vernier height gauge?
It is also used to measure the straightness, squareness, or perpendicularity of objects.
15. The material used in vernier height gauge is
Steel
Cast Iron
Plastic
Aluminum
Answer.1. Steel
Explanation:-
The principal components shall be of carbon steel or stainless steel. The coefficient of thermal expansion within the temperature range of 10°C to 30°C shall be within (11.5 ± 1.0) × 10 –6/°C. The measuring faces of the sliding jaw and the underside of the base shall be hardened to not less than 700 HV for carbon steel and not less than 500 HV for stainless steel. The scriber shall be hardened throughout to not less than 700 HV. Finished height gauges shall be free from internal stresses
