I very much enjoyed this video on fettling a Harbor Freight #4 plane, presented by Woodshop Companion on youtube.
It was a random algorithm suggestion.
The presenter, Nick Engler, has the lovable persona of a Disney Christmas movie uncle, and has an unhurried but knowledgeable style.
The most interesting part is his investigation into what steel the cutter might be.
https://www.youtube.com/watch?v=QSnLgE7fWCQ