In addition to searching individual online equipment catalogs (for example, SnapOn, Fastenal), you may also try these sources: 

Thomas Register HD9723 .T5 (5th floor Valley Library)
A large set of green catalog volumes. Use to find suppliers of industrial products and services in North America. online as ThomasNet

Sweet's Catalog File TH455 .S95 (1st Floor Valley Library )
A compilation of product catalogs for the construction industry. Online as Sweet's Network.