Hardware and wood working resources

Hardware hut:
http://www.thehardwarehut.com/index.php
They carry a wide range of products. I came across them in the search for organizing drawers and cabinets for my kitchen. No exactly stagecraft related, other than we often have a variety of odd objects that need to be stored, and special hardware that needs to be found for specific scenery purposes. And this place is a nice blend of both.

http://www.deerwood.com/catalog/index.php
Deerwood fasteners are a good resource for square head screws. I have mixed thoughts about square head screws. But, some will swear by them. Nevertheless Deerwood also has a fastener guide located at:
http://www.deerwood.com/catalog/wood_fast_guide.php?osCsid=b6ef79c9d6b1227fc40db53343be11e9

And just for fun:
http://www.mockett.com/default.asp?ID=4&action=detail&partCode=WM24
Check that out for some fun. Clever idea, fun, and useful - what more can you ask for in product design.