There's a bit of a cult classic book, "Pocket Ref" by Thomas Glover, and its big brother "Desk Ref." They're just books that attempt to provide reference tables

There's a bit of a cult classic book, "Pocket Ref" by Thomas Glover, and its big brother "Desk Ref." They're just books that attempt to provide reference tables for most of the things you'd need to look up throughout a wide variety of technical fields, but especially mechanical trades. A random selection of the contents includes "Densities of Gases," "Plywood & Panel Grading," "Canada & Mexico Postal Abbreviations & Capitals," "Solid Figure Formulas," "Commonly Available Pumps," "Welding Electrode Amperages," etc. Sort of a monument to what's possible in a reference work, and cheap insurance to throw in your toolkit or vehicle if you do any kind of field work for when there's no cell coverage. I also have a book of mathematical tables, mostly for historic interest, but I think there's also some value in working from trig or log tables as I find looking at the table a few times helps you develop an intuition for estimating the function a lot faster than the attempts some textbooks make.