How Do You Calibrate Measurements?

Super Article, I loved the bit about the Cubit being the length of the Pharaoh's fore-arm. The ubiquitous '666' I understand, came from a triangular calibration box. round seeds were placed in the box up to the 36th line, ( 36 +1 +37, 37/2 = 18.5, 18.5 x 36 = 666) The contents were poured into the weighing scale pans, 333 +333, then the contents were exchanges from one pan to the other. If that test was OK, a further amount of seed was weighed i.e. 333 seeds. that was added 666 + 333 = 999, finally the scale was tested for sensitivity, one seed. if a single seed unbalanced both pans, then all thousand seeds were placed in one pan and the traders weights were tested.

All going well, the trader was thanked and the executioner placed his sword back in it's scabbard. Had a single mishap occurred, the trader would have seen the sky about half a second later, or that's if a severed head can see at all. 666 = a beastly end. Interesting how Imperial weights were in fact metric '1000' seeds.

Standards and calibration are ever more vital in manufacturing, because many goods are assembled from components that might be manufactured anywhere in the world. one faulty component can halt the assembly line. I shuddered at the description of a delicate instrument being handed to a clumsy postman after calibration.

calibration of measuring instrument is things of motorlogy bereau not NDT.

NDT can only place an important action in testing and inspecting processing when a products is producing.

I think. they are very different.

Rght?

Traceability to the National Institute of Standards and Technology (NIST) is the all important factor 'cnpower' NIST so to speak is the modern equivalent of the 'Pharaoh's Arm' length used to standardise the Ancient Egyptian Cubit.

Thanks for an excellent and informative article. I've filed it away for future reference. JEJ

Ditto, Thanks, very useful piece of reference.

Calibrating can pose a problem or two, way back in 1969, there lived a sweet lunatic named David Wier, in a lovely little mews cottage off Sloan Street London. He was addicted to fast cars, and could afford them. Another sweet Police Inspector had a very pretty daughter that the Late Royal Photographer dedicated two full pages to, giving the excuse that most of the models had what he regarded as a best angle, Stephanie was 360 degrees and he could not decide........The poor father of this model had to cope with preparations in the dead of night, whilst motor cars were prepared for the Le Mans Race. One test was 'Flat out in top gear. so as to ascertain the best acceleration etc. David Wier drove for Porshe..and the best stretch of road was the A1 near Northallerton in Yorkshire.

This particular year Chief Inspector Granger was going to issue a speeding ticket, but naturally his equipment was not calibrated for those kinds of speed. That did not deter the intrepid Chief Inspector. He stationed two teams of Traffic Police with stop watches......

Mr. David Wier was summoned to court, he was timed at over three hundred miles per hour......For Le Mans...a lower ratio gearbox would be used. this was just to test aerodynamics.

The three magistrates sat patiently whilst each police officer gave their evidence.. blah blah

Finally the Sober Yorkshire Magistrates retired to reach their verdict.....

The returned to the bench, and summoned Chief Inspector Granger,

Then they proceeded to lambaste him as a disgrace to the Yorkshire Constabulary and for wasting court time to boot. It was perfectly clear, This was a simple case of the 'Two Car' trick. they knew all about it from their University days. How on earth could a senior Police Officer be fooled by such an obvious prank.

David was dismissed.

When the equipment is accurate, what do you do if it goes off the scale?

Chief Inspector Granger had the last laugh. He arranged that Le Mans included a chicane on the Mulsanne stretch, to ensure motor cars kept to reasonable speeds. especially on his patch.