You should add in Calvin Schmid's Handbook of Graphic Presentation into your list Doug -- https://archive.org/details/HandbookOfGraphicPresentation/pa... Unfortunately I do not see specific discussion of how to make the lines a consistent thickness. It does have notes on how to sharpen your pencil and how to use a carpenters spline to draw smooth curves though.
If you're inking your drawings, you probably don't need to worry all that much about the exact line width and consistency of your pencil work.
N.b. I don't ink my drawings. I've used drafting pens a couple times to experiment, but it's not part of my regular workflow.
https://www.jetpens.com/blog/The-Best-Technical-Drawing-Pens