calibrating protractors 2

[rubepierre]

would someone say yes the question of "Can protractors be calibrated?"..I know they can but you need a standard or something which we do not have here...
Thank You. ..

 

[randi]

To be able to calibrate means you are able to make an adjustment, whether it is an adjustment of "Zero" or "span", which means being able to shrink or enlarge the entire range by a span adjustment device. You can notice that this does not apply to fixed scale items like rulers, tape measures and mechanical, fixed scale protractors.

However if you or someone had a master protractor, which the people who make such devices like " MITUTOYO" or " Brown & Sharpe" or " DOALL" etc. must have - You should be able to perfom a calibration check. This might utilize a technique like the use of a "Shadowgraph" or an "Optical comparator". They must have established the pass/fail or go-No go criteria.
Because shadograph has a mgnification as well as a x-y movement feature, you should be able to perform such a check as these devices have varios standard charts available that are made by reputable firms like TECHMET or Baush & Lomb etc. Good luck with your search.

 

[IRstuff]

Actually, even non-adjustable things can be calibrated; although the meaning would be somewhat different.

If the instrument is adjustable, then calibration involves getting the instrument to match reference standard, by changing the gain or offset or both.

In the case of something like a voltmeter, what is sometimes done is that the measurement remains the same, only the display is different. If the measurement is 1.0 V, but the calibrator says that it should be 1.06V, then anytime you get a measurement of 1.0V, you output 1.06V

Likewise, in the case of a ruler or protractor, the calibration would be the creation of a lookup table with the correct values, so that if you measure 60 degrees, you look up that value in the table and see what it really corresponds to, based on the calibrator.

TTFN