Thank you. Yes, it highlights the difference in approach and outlook. You come from a QC/inspection background, I come from a manufacturing engineering background. As such, you're highly focused on outcomes, ie. no rejects escaping. Meanwhile I see the goal of QC as not to spot rejects, but to spot problems with the manufacturing process itself, so they can be corrected and eliminate the production of rejects in the first place.

So you're right. To me it's all about the process, and I live by that. The guiding principle is trust the process, have a process you can trust.

Going back to the wagon analogy, you missed that the "product" is the safe delivery of a wagonload to the destination. You would add extra crew in case the wagon went off the road. I'd save that dough and hire better drovers who can be relied to keep the wagon on the road. The test of the approaches would be which would most consistently deliver wagonloads at the lows cost. (cost is ALWAYS a factor).

BTW- you're wrong in assuming that those of us who build without tensionmeters are living on blind faith in our abilities. We do use them as a QC device following the rules of statistical process control (sometimes without knowing that's what we're doing).

All of this begs the question you should be asking. Why/how are some people able to build true, evenly tensioned wheels without a tension meter, while others can't? and more specifically, how did my changing his focus move the OP from building potato chips to wheels?