I am going to ressurect this thread as I am working on a similar calculation. We utilize 40, 30, 20, 10, 5, 1, and 0.5lb weights. These weights are utilized in stress rupture, sustained load, and creep testing machines. I need to calculate an uncertainty budget for the weights themselves.
For calibration of these weights we utilize a set of master weights calibrated by an accredited outside laboratory which reports a MU for each weight size.
0.5lb- UNC=3.3 mg k2 coverage
1.0lb - UNC=3.3 mg k2
5.0lb - UNC=8.1 mg k2
20lb - UNC=65 mg k2
Now, if I take 10 measurements on the scale we use for calibration of our working weights against the masters for the 20lb weight I get a std dev of
0.020138lb, I then take this number and divide it by the square root of 10...this should be my type A unc?
So, at this point I would take the unc from our master weight at 20lb and divide it by 2 to return to STD UNC? Then square the type A, B unc values add the squares and take the square root of this number...then multiply this number by 2 to obtain expanded uncertainty.
Does this sound correct for determining the UOM of the 20lb working weights?
There is no way around it, Uncertainty of Measurements is most definately going to give me a headache!