To calibrate your measuring equipment on your own, you need following things:
1)A master gauge or instrument which is calibrated by an acredited laboratory.
2)The least count /precision of the master should ideally be 1/10 of the least count of your instrument.
3)The environement of the measuring room should be controlled as required in calibration standard.
4)You shuld document a procedure of calibration for the instrument in question specifying method of calibration and acceptable variation.
5)The acceptable variation should be capable of achieving the precision required by your product.
If you have the above five things, nobody can stop you from doing your own calibration. Please note the key here is, you can fix your own precision level depending on your product.
The calibration standards are designed for the aerospace industry for which you donot have to waste money.
V.J.Brahmaiah
Some of these statements are inaccurate!!
Calibration is a science which has application even at the level of the traffic police, performing speed checks and enforcement. Many people think they are doing calibration 'in-house' but don't posses many competencies (not just training) or the resources to perform calibration and waste money that way. Often they don't ask an outside lab for the correct service and take what they are given, but that's not a good reason to take calibration 'in-house'.
I believe your statement regarding the aerospace industry underlies your basic misunderstanding of the science of calibration;
Comment # 3 - Environmental conditions don't have to be 'controlled', they must however be known. There are many situations where money is wasted on a controlled envronment room, just for a few hand tools!
Comment # 4 - Is any old procedure going to be OK? If you calibrate an outside 0-25mm micrometer, for example, is any position along the scale acceptable, or how many should be used etc? There's a lot more to be considered than simply writing down what someone thinks should be done!
In #5 - What do you mean? How is a person to determine acceptable variation? Should someone calculate the uncertainty of measurement for the device? Peform linearity, bias and stability studies, is this what you mean?
Without clear understanding of the nature of calibration and the requirements for an effective system, the so called savings of doing calibration in-house can soon be lost through incorrect calibrations, wasted time and the negative effects on product and customer satisfaction!