Those first two companies don't sell to people, just to companies. I don't know about the third, their website seems to be down/unregistered (I have found the same link with my own search, and you did write it down correctly, but the website itself is shot).

Anyhow, you can find a lot of companies that specialize in mechanical engineering parts/supplies (did you know that the largest diesel engine in the world was recently built in Finland?) here, but they are all apparently "too important" to sell to individuals.