ABSTRACT
Let's pause at this point and see what those errors suggest. Plus 34% means that some of our bolts will experience 134% of ideal or optimum tension because of the combined assembly and service factors considered so far. Minus 39% tells us that, worst case, we can count on only 61% (100%-39%) of the desired clamping force in some of those joints. The ratio, therefore, between the tension the bolts must be able to support without breaking and the clamping force we can count on in 99% (3 sigma) of our assemblies in 134%/61 %; in other words, the ratio is greater than 2:1.
