A mock truncated cone was manufactured and sent to 12 participants throughout the world for measurement of appropriate dimensions. The results indicated that the error in measuring the cone diameter was trivial while the cone angle and truncation height had errors of ±4.79% and ±12.4%, respectively, based on the standard deviation of all measurements. Two groups had reported values of the cone angle which were statistically high and when these values were ignored the error in the cone angle was reduced to ±1.38%. These errors are lower than previously quoted accuracies in the literature. Since the measurement techniques used for the five most accurate measurements are not new, it is concluded that care of the person performing the measurement is critical. The effect of errors on the geometric variables’ values on the shear rate, shear stress, and first normal stress difference are discussed.