I'm putting this under construction as the parts would be part of construction--maybe wrong category.
The Small Parts Inc company produces and sells from others smal prts that are often difficult to get. I've had their catalog for years, it's a download on their site, and they have the most amazing things. miniature, gears, pulleys, screws of all sorts, wrenches, drills , fasteners, couplings,pivots, bearings, shaft collars and things that can make a building job so much easier. have a look--it may prove to be useful at some point in time--I hope so.
http://www.smallparts.com