Welcome Bill. One place to start looking is thrift stores and second hand appliance dealers. You might also call small appliance repair companies. When you talk to these dealers and repair places, you are going to have to be specific about what you are seeking. Be prepared to give them brands and years, especially if you are interested in any Frigidaire appliances where the year generally shows up in the model number. Offer them pictures if they will listen to your request and make little vertical strips at the bottom of the pictures with your name and phone number that can be easily torn off in case someone finds something. Offer a bounty of whatever you think you would be willing to pay them for finding machines and going to the trouble to call you. Talk with these people about various mechanical, performance or design elements you like about the machines.
Years ago when I was in Sarasota, FL, I stopped in a place by the name of Whiteside's Appliances. I had looked through the Yellow Pages and found some listings to check out. They had a big Frigidaire sign from the 60s in the window. The young man I talked to at the counter was the son of the founder. As I was telling him about our collection and how much we appreciated the design and features of Frigidaire and other brands of ranges from the 50s and 60s, he opened the gate in the counter and said that he wanted to show me something. In the rear of the store he had a Hotpoint 40 inch range from the early-mid 50s and a couple of Frigidaire ranges. None of the models were top of the line, but they were in good shape. He told me that he had pulled them in when he delivered new ranges, but these were too nice to throw out. It was like he was sharing his secret with me, someone else who apreciated the lines and features of these old ranges. He had shelves of parts and told me he would be glad to check for parts if I sent him part numbers. He said that he had mostly range parts and knew the various clocks and Cookmaster controls of 50s and 60s Frigidaire ranges. In a Salvation Army (?) thrift store there, I found an almost unused Frigidaire 30" Super (bottom of the line) range from 1961 or 62. I guess it had been in a guest quarters apartment or vacation home that was being remodeled.
Sometimes old appliances can be found in the back of auction barns or second hand furniture places. A long time ago, many furniture stores had a line of appliances. They were not heavily promoted, but sometimes something old would wind up in the basement or warehouse. The same can be said for old, vanishing independent hardware stores in smaller areas. King Hardware was such a chain in Atlanta. In the early 60s, they sold Frigidaire and usually had a washer on the floor. Earlier, they sold Philco-Bendix and then Speed Queen. I remember that they had the model with the little box between the control panel and the lid that served as a dispenser. Hardware stores are often a great place to search for housewares, especially things like pressure cooker parts and filters, etc for vacuum coffee makers. Since housewares were not the main focus of the store, old stuff often got pushed to the back of the shelves and the Presto Pressure Cooker repair chest is often still full of treasures. Old pieces of Pyrex, electric skillets and sometimes vacuum cleaner parts can be found also.
All you need to do is keep appliances on your mind all the time. When you go out driving, watch curbs and alleys, look for old stores, flea markets, anything that looks kind of dusty and maybe not so well lighted. These are the places where things come to a rest, waiting to be found. I don't know if you will understand this, but if you have dreams of finding things that you really, really want, you will be lead to them. It has to do with the positive energy on which the universe operates. When you keep an image in your mind, forces will work to bring dreams to fruition.
Also, go to libraries around you, the bigger and older the better and read old bound volumes of Consumer Reports & Consumer's Research Bulletin to become familiar with vintage appliances. If you are interested in learning even more, check out the bound periodicals if they have not been converted to microform. Saturday Evening Post was a treasure of Westinghouse ads not seen in other periodicals. Better Homes and Gardens Magazine from the early fifties through the early 60s had an Index to Advertisers in the back of each issue. You will probably want Appliances, Major. In many issues back then when so many appliances were new on the market, you will find articles on features of new washers, dryers, ranges, ironers, dishwashers and sometimes related articles about how to get the most use out of these new appliances. American Home and, to a lesser extent, Ladies' Home Journal had appliance ads and articles. A word of warning, Saturday Evening Post and Ladies Home Journal had some fabulous fiction back then and it was not just gushy, romantic stuff, either, so you can get pleasantly sidetracked reading stories. Home & Garden, Life and Look have the fewest appliance ads. If you have the time, you can spend countless hours learning a lot from old periodicals.
Check the classified ads for estate sales, especially in older, wealthier neighborhoods where an old appliance might be in a corner of a basement.
Happy hunting,
Tom