Can't tell you haw many times consulting the good book has been my salvation, both at work and at home.
A friend in Switzerland once picked up a rather expensive bit of American kit from a dealer in the Netherlands and it showed up missing fasteners. The dealer wasn't helpful at all and his local hardware stores didn't know what to make of SAE threaded parts. Being his only contact in the USA he asked for my help.
Turned out the manufacturer is in my back yard and I had a pleasant conversation with one of their engineers. Unfortunately, we couldn't figure out what revision of the unit my friend had and the fastener configuration had changed at various revs. He offered to fix it for free if my friend sent the unit back to the factory, but shipping back and forth from Switzerland was way too expensive.
Out came the good book. I picked out a selection of the possible bolts, USA made stainless steel, and McM-C shipped them to my doorstep in one day. The cost of the bolts and shipping to me was less than 20 bucks. Cost me more to turn around and send them to to him. They worked and he was up and running. Another win for McM-C and US industrial infrastructure.
Hot tip - As huge as their catalog is, it doesn't have everything (although it sure seems like it). If there's something that isn't in the catalog but is made by one of their suppliers, they'll special order it for you.
A shout out to Tim Allen for having a "yellow bible" prominently displayed on Tim "the Tool Man" Taylor's shelf in Home Improvement. Also to the animators of Big Hero 6 for the same.