I found a very useful YouTube channel where the guy covers how to take critical measurements like run out.
Mr. Kelly is a fantastic instructor. Weber Auto videos are top notch.
He is the same guy all the EV builders refer to for teardowns. I actually thought he specialized in that. He has physical, waterjet-cut bisections of motor and gear assemblies, brightly labelled and arranged on boards, and has many hours-long disassembly, explanation, and reassembly videos that seem like they're only a few minutes long.
Also, not that it matters, but the guy is a parapalegic. So all this mechanic work is not exactly easy or convenient for him. He can't just lean and grab things, he can't pull and heave things like the rest of us can, he has to leave room for his wheelchair in every situation. Extra challenges and unless you see him moving around, you'd have no idea.
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My favorite bodywork channel is Fitzee's Fabrications.
My favorite thing about him is that he doesn't use fancy tools. He has fancier tools, but he barely ever uses them. It's all grinder and welder. His methodology is always to break the task into simple segments. It usually takes more time and more work, but without complexity or multiple things depending on each other being perfect. You just solve one task a time, and put them together one at a time. It's something that speaks to a hobbyist, because it's frustration-free. Takes all the stress and complexity out of bodywork. You just have to be patient and methodical and then every part is easy to do.
I wish I'd seen his videos before I'd started my bodywork. I actually found his channel when I was feeling most disparaged about the new rust holes I found in my car and the ensuing exterior (visible) work I would have to do, that I thought was beyond my ability and I was going to butcher. I haven't attempted any more bodywork yet, but I'm a lot less intimidated by it after watching him do exactly the repairs I have to do. I'm confident that if I just take my time, it's all solveable.
And he's a delightful person. He's active in the comments, he reads them all, and he answers as many questions as he can even if they're the same common questions he's answered lots before, he takes his time to help everyone.