Hi Summerstorm. You asked, "Can anyone tell me the advantages and difference in the following models?
The singer 301 and the singer 404?
Is the 404 aluminum?"
I have both the 301 and the 404. The 404 is heavier than the 301. I read today on the web that the 404 is more sturdy and durable than the 301. This is the website where I read the information on the 404.
http://www.free-guitar-tablature.com/404.html
Both machines have slant foots which make it easier to see where you are sewing. The 301 uses the same bobbin case and bobbins that the featherweight uses. The 301 is a vertical bobbin.
The 404 uses the class 66 bobbins and has a drop in bobbin case.
The website that I just posted talks about the 404 being heavy, but it isn't too heavy for me to carry. (I'm not that strong.) If I had to carry it a long distance (like to a quilting class) I would put it on a luggage carrier. It isn't that difficult for me to carry from one room to another room.
I like both the 301 and the 404. I essentially got the 404 because it was in a cabinet that I wanted. I planned on donating the machine to someone after I took it out of the cabinet but I thought of a use that I could use it for, so I decided to keep it.