Feels like a chicken and egg senario. Let’s say I get my torque wrench from work sent off to be calibrated, and that’s calibrated with something itself needs to be calibrated, and so on and so fourth. How’s that figured out?
In: 430
Each tool is calibrated by another, more precise tool. Eventually you work your way back to a “master standard”, which is some sort of tool or measurement which effectively defines the measurement. For instance for units of length; a factory making rulers creates the marks based on a set of calipers or micrometers. Those calipers or micrometers are calibrated to a set of reference bars which are extremely precisely ground, and certified to be a certain length. The factory which makes the reference bars uses an even more precise set, which comes from a laboratory with a master “inch” measurement. Currently, length is defined based on precise tools for measuring the wavelength of light, so the precision of the light wavelength measurement sets the precision of the everything down the line. In the olden days, there was actually a platinum bar that was considered to be an inch long. It was kept locked in a special vacuum filled safe, and every few years they would take it out and use it to calibrate other instruments.
Feels like a chicken and egg senario. Let’s say I get my torque wrench from work sent off to be calibrated, and that’s calibrated with something itself needs to be calibrated, and so on and so fourth. How’s that figured out?
In: 430
Each tool is calibrated by another, more precise tool. Eventually you work your way back to a “master standard”, which is some sort of tool or measurement which effectively defines the measurement. For instance for units of length; a factory making rulers creates the marks based on a set of calipers or micrometers. Those calipers or micrometers are calibrated to a set of reference bars which are extremely precisely ground, and certified to be a certain length. The factory which makes the reference bars uses an even more precise set, which comes from a laboratory with a master “inch” measurement. Currently, length is defined based on precise tools for measuring the wavelength of light, so the precision of the light wavelength measurement sets the precision of the everything down the line. In the olden days, there was actually a platinum bar that was considered to be an inch long. It was kept locked in a special vacuum filled safe, and every few years they would take it out and use it to calibrate other instruments.
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