Reference Material; dusty, digital, diverse, desperate?
I'd like to respond as well; somewhat in order of importance. Order is related to how long I regard them as a resource, but not entirely. Some have become difficult to examine separately.
I have a personal library, collected over what seems to predate my first employment to this very instant. Texts are like music. An effective description paints a picture that you comprehend at your level. It is composed of various editions of Machinist Handbook, Colvins, Marks, I find, not duplicates. Manufacturers manuals and catalogs. Advertisement sheets. Textbooks & Reference books in general; on engineering, mechanics, tool design, welding. US NAVY Machinery Repairman (stupendous!), Hull Technician, Boatswain Mate, Gunners Mate, and Electricians Mate to some degree. They are separated by paygrade (E4, E5, E6 and E7)which equals responsibility in the service. Those beyond address mainly administrative topics. I advise anyone at any level interested in machine work to beg-borrow-steal Machinery Repairman's 4-6. They are digital now, print copies are best. The ARMY certainly has equivalent reference material. All generated by the the U.S. Government Printing Office. They are without classified material, and just outside public domain but available.
Next has become the web; but only because the library allows me to screen questionable material. I use Google only for search engine, and Copernic for academics. Wikipedia is good enough to be third in line. Google brought me to HMT, so it equals Google for direct searches. Participating there is just plain fun, and unexpectedly rewarding. Web focus on visual input detracts what could be just as effective as text. But even textbooks are illustrated. I can only echo what others state on HMT.net, it is staggering. Youtube usually disappoints me, instructional content turns out to be more self serving promotion than educational. Or so poorly staged you can't see what is delivered. A requisite directing and production values course should be mandatory before you get a channel. It is far better for historical and archive material. I'm glad our taxes support that for sure. Same for Pinterest, I like to aim my work to interested parties, not passerby. The trick is learning to manipulate and SAVE search terms; in both general info and very pointed searches. Bookmarks classify into narrowly titled folders; logically subbed of course. Don't forget, you can notate pages differently in bookmarks differently than the web pastes automatically. I wouldn't say I have lots of interests, but varied and interrelated at the same time. Oddly enough, I catalog (curate?) music online in the same manner. Bye bye Grooveshark, hello Spotify. Want something different? Search a11four1 T(or t)oolmaker51 everywhere else
Moving from California lost most interpersonal contacts, most regrettable. However, there is this thing called the web...and cellphones. Midwest hasn't displayed the population of machinists like I grew up with, even a retired Public Safety Chief for LA Sheriff. Hi FB!
I keep a small set of notebooks; paper and finepoint pen. Mostly incidental solutions, that may need to surface again. There is no proper front or back. Answers are written on right-hand pages, revelations or stumpers on the left, after the book is turned around. I carry a file of whatever the current project is as a brainstorming record. Right now it is all about the electrical project, gauges, wire fill, project of making wireway hangers, building the punch stand, amps/hp/volts of the equipment...The un-bucket tool bag began there.
And finally, as others have said our experience is valuable for own self and others. Fix or fail, each has some bit of worthwhile potential to refine.