Some Machining related channels on youtube:
this old tony, Chronova engineering, cylo's garage, inheritance machining, breaking taps, blondie hacks, tarkka, dan gelbert, Jonesey Makes, Eric(with a K), Clough42, Alec steele, NBR Works, Not An engineer, Stefan Gotteswinter, oxtoolco, ROBRENZ, MrCrispin, Clickspring, Artisan Makes, MH Anything, Jellyfish machine,Maker B,
And also there is great course on precision engineering by Alex slocum:
https://m.youtube.com/playlist?list=PLksE8LDXGXl_MQHKr2DqhfD...
https://www.youtube.com/@Chronovaengineering
https://www.youtube.com/@cylosgarage
https://www.youtube.com/@inheritancemachining
https://www.youtube.com/@breakingtaps
https://www.youtube.com/@blondihacks
https://www.youtube.com/@tarkka
https://www.youtube.com/@dgelbart
https://www.youtube.com/@JoneseyMakes
https://www.youtube.com/@Erik-not-Eric
https://www.youtube.com/@Clough42
https://www.youtube.com/@Alecsteele
https://www.youtube.com/@NBRWorks
https://www.youtube.com/@NoEngineerHere
https://www.youtube.com/@StefanGotteswinter
https://www.youtube.com/@oxtoolco
https://www.youtube.com/@ROBRENZ
https://www.youtube.com/@MrCrispin
https://www.youtube.com/@Clickspring
https://www.youtube.com/@ArtisanMakes
https://www.youtube.com/@MHAnything