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Which standards are popularly used internationally
to check different types of dial gauges?
In India IS 2092- 1983 is used for plunger type dial gauges
while IS 11498-1985 is used for lever type dial gauges In Europe,
DIN 878 - 1983 is used for plunger type dial gauges while DIN
2270 - 1985 is used for lever type dial gauges In USA, ASME/ANSI
B89.1.10M
- 1987 (Now its 2000)
is used for plunger as well as lever type dial
gauges In Japan JIS B 7503-1997 is used for plunger type dial
gauge while JIS B 7533-1990 is used for lever type dial gauge
ISO has published its recommendations for plunger type dial
gauges ISO/ R463-1965 but it is not a standard yet. |
What is more important gauge R & R or the
uncertainty in measurement?
Both these are having different purposes. While accepting a
gauge for shop floor use you may want to check its R & R before
putting into service. On the other hand while calibrating a
master you would want to decide its size with certain uncertainty
of measurement. Similarly, while calibrating an instrument you
would want to decide its error with some uncertainty in measurement.
For all practical purpose the above answer lays down sufficiently
accurate guidelines. |
Can I reject a standard instrument like
a dial gauge by applying criterion of gauge R & R and send it
back to its manufacturer?
Surely not. Probably no manufacturer will accept it. Such instruments
generally conform to well known national and international standards.
Gauge R & R tells you whether a given gauge is suitable for
your own specific use. Probably your selection of instrument
for that application is wrong. You can not apply this acceptance
criterion to reject a dial gauge which is a general purpose
instrument. |
Does subzero treated master expand or contract
as the temperature changes?
Surely it does. This is a common misconception. Subzero treatment
does render dimensional stability to a gauge. It means that
with passage of time its size does not change due to modification
in internal molecular structure ( Retained Austenite to Martensite
and all that ) However, there is no change in its behaviour
with respect to temperature. |
Can I use a gauge whose hardness is equal
to or slightly more than my component hardness ?
It is not recommended. Your gauge should be 10 Rc more than
component. Of course, I am not talking about NOGO gauges. |
Can you give us some references on uncertainty
in measurement?
The best source is internet. Go to search engine GOOGLE.COM
or any other search engines and type 'uncertainty in measurement' and you will have all the data you need.
You will also get two page print out listing
down all the references on this topic if you click on www.microserve.net/~iso25/biblography_of_uncertainty.htm. In case you come across any problem, please contact
us, we will help you |
What are unilateral tolerances ?
Unilateral tolerances are those tolerances in which there is
no mean. An example will make it more clear. Take tolerance
of roundness, squareness or concentricity. Whatever value specified
in the drawing is maximum permissible value. This is not the
value which we should aim at. On the similar lines, some tolerances
are specified as minimum permissible value. Generally tolerances
related to material properties like hardness, tensile strength
etc are specified in this way. In a nutshell tolerances when
specified as a maximum or minimum permissible
limit i.e. single sided, are known as unilateral tolerances . Accordingly both sided tolerance is known as bilateral tolerance. Generally all geometrical tolerances are unilateral while dimensional tolerance is bilateral |
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