For anyone who wants an ASMR video to relax to, here is a complete tear down and reassembly of a watch. I can only dream of being able to do something like this. I have struggled so much even getting little tiny screws back into their holes.
You do realize of course this is like me telling Tautech how to use a scope. Or relying on YT to explain earthing and isolation transformers.
Then all parts but the mainspring are put into the machine. EVERYTHING is disassembled. You cannot get things like capped jewels clean wi/o disassembly. Then parts are handled with finger cots and I use only bronze tweezers. Oils pots are changed at least weekly. Cleaning solutions at least twice a week. "Stains" are removed with lab grade heptane. Surgical sponge swabs are used to remove dust and only a vacuum is on the bench, no compressed air.
All work is done under at least 15X, inspection of parts and oiling at 60X.
This is in MY shop. In parts accounts shops you now need a clean room atmosphere. Plus ventilation to remove the fumes from the cleaning machines which are to be in a separate room that can be closed off.
While the uninitiated may think this is silly, it reduces the risk of contamination of the lubricants. And while many bemoan the cost of the lubricants and the cleaning requirements, there are two reasons for this. One is to ensure compatibility of the lubricants should they come into contact with each other. We even now use teflon coated mainsprings so we only lubricate the MS arbor and in automatics the MS barrel wall.
The other reason is the standards are not written for independents, let alone amateurs. They ensure longer life of cleaning solutions in the service centers that have to comply with very strict disposal laws, So they do no want incompatible lubricants contaminating their solutions.
FWIW, adhering to these standards, my comeback rate on watches was around 2 percent. Which is considered way too low for profit. Should be closer to 10%. But since most of my work was and is period correct clocks for warbird and vintage aircraft, I need to avoid the inconvenience of pulling the piece from the instrument panel because of my error. Years ago I tried doing work based on price and found that either I could do correct work or cheap work, but I could only do one or the other. I chose the former which is how you get customers who are physicists and engineers (from Los Alamos and JPL), astronomers from the US Naval Observatory, command pilots and blue water navigators. People who understand precision instruments and the skills required to maintain them.
So yes, there are those who are naive and think they know better than a fully trained watchmaker who charges twice as much.
But then, there are those who think they should work on high energy circuits using a $30 multimeter.
The former can live to spread their stories. The latter seem to be self-limited by circumstance.
Here are pics of my shop as I left it last nite. Bear in mind I "distracted" by my new hobby (EE) so it is not as organized as I like to keep it.
Oh, forgot. After the watch is reassembled it's correct function is verified on using performance analysis instruments (beat error, amplitude and rate in all positions), run for 7 days and also visually and functionally by one of us that did not do the work. If any parameter falls short, the watch is inspected and on the bench until the fault is found, visually verified and corrected. Then the QA process starts again from the beginning.. In short, strict quality control.
As was said by one of the most famous teachers "It is one thing to make a watch tick, it is quite another to ensure it functions as originally intended". (which means as a precision instrument).