I'm glad Joe told you how to post pictures.
There are two manuals for the 401 at
https://www.singer.com/search/support?title=401 One at the top and then one further down the page. One is from 1958 and the other is a revised in 1976 version.
While it is fairly long, there is some good info at
Shall I try and get this machine? There are a couple of others at
401a problem and
She's real fun, my 401... particularly
She's real fun, my 401...
Janey - Neat people never make the exciting discoveries I do.
Not affiliated with off-site link(s)