Difference between line and end standard
Answers
1. When the length being measured is expressed as the distance between two lines, this is known as line standard.
2. A scale is quick and easy to use over a wide range of dimension.
3. Line standards are not as accurate as end standards and cannot be used for close tolerance measurement.
4. A steel scale can be read to about ± 0.2 mm of true value.
5. The scale graduations are not subject to wear although significance wear on leading end leads to undersizing.
6. Scales are subjected to parallax error of reading. They may be positive or negative reading.
7. Errors due to inaccuracy of graduations engraved on the scale are possible.
8. A scale does not provide a “built in” measuring datum.
Comparison # End Standards:
1. When the length being measured is expressed as the distance between two surfaces or ends, this is known as end standard.
2. They are time consuming to use and prove only one dimension at a time.
3. End standards are highly accurate and well- suitable to close tolerance measurement.
4. Close dimensional tolerance as small as 0.0005 mm can be obtained.
5. They are subjected to wear on their measuring faces. Also wringing of slip gauges leads to damage.
6. The parallax error is not associated with such type of measurement because the distance is measured between two flat surfaces.
7. Such errors are not possible with end standards.
8. They have a “built in” measuring datum as their measuring faces are flat and parallel.
Answer:
end standerd is greater than line standerd