[Richard]

I have found some catalogs that over the years are very informative resources for exposing me to either “that’s how they do that” or “oh, that’s a part I didn’t know existed”. I find that reading some of the catalogs is extremely educational when it comes to techie stuff. Now, I am not dissing YouTube or internet search engines, but there is something about old school in print that I retain better. Most of these catalogs stay in the “library”.  You may have to pay a bit for one or two, but here is my list of go to reference materials. I am sure you have yours, and I would love to hear of them. I may just use the catalog to learn the name of what I am looking for, and then utilize a search engine. Or in the case of McMaster, pay the premium price for a quality part and quick reliable shipping. 

McMaster Carr
Grainger
Jamestown Distributors
Sailrite

Less used but useful nonetheless.

Summit Racing
West Marine
Eastwood