It's actually not that hard to hold sizes within a bit better than a couple thousandths of an inch if you transfer the caliper feel to a micrometer.
When I see these videos, from my perspective as someone who hates having to re-do something because it wasn't done right it just seems like a giant waste of time to me. While I can see the perspective somewhat of low cost repairs, they aren't that low in cost if they need to be done again and again and again vs. done one time the right way that lasts way longer. I don't think the repair cost is the issue, probably it's more the outlay for the equipment required to do things in a more proper way for longevity. That would drive the cost of repairs up a little bit, but the initial outlay is probably the big problem.
You reminded me of this:
Years ago, I got to "help" a friend run his combine harvester through a field of hay. I'd never seen the process before, and it was fascinating. And the brand new harrow bed was even more fascinating. But to the point:
The harvester had a paddle wheel on the front that rotated and fed hay into a cutter that slid just above the ground. At least the paddle wheel was supposed to rotate. If something -- a rock, a stick, a small animal -- jammed it, a shear pin would break and disconnect the wheel from its drive mechanism, preventing damage.
To work properly, the shear pin had to be strong enough to carry the normal load, but weak enough to break if the load increased too much. That's a tough design challenge, and shear pins are manufactured for a specific application.
Max had a spare shear pin on the combine and quickly replaced the broken one with it, but it wasn't quite the right one, so it broke a half hour later.
We shut down, and drove back to the shop. The box of shear pins was empty! To get another box, we'd have to drive the five miles into town, get the pins, and drive back. That would take too long, Max said, so he grabbed a roll of bailing wire and we headed back to the field.
Max jammed as many two inch long pieces of bailing wire as he could into the shear pin hole and hopped back into the machine.
Five minutes later, when the too-soft make-shift "shear pin" broke, he jammed in another bundle of bailing wire.
Five minutes later, it broke again. He fixed it again.
Five minutes later, he fixed it again. Am I starting to repeat myself?
Because we didn't have the right shear pins, we spent hours in the field getting a half hour's work done.
I learned an important lesson from this experience. I call it the Farmer Syndrome:
There's isn't enough time to do it right, but there's always enough time to do it wrong -- again, and again, and again.
