rupe,
Welcome to the QB.
I'm not familiar with Sterling machines, but yours sounds like one of many Japanese made machines that were imported post WW II up to the 60 and 70s.
If you could post a good close up front view picture of the machine here it would go a long way to identifying it.
Relics {
http://www.tias.com/stores/relics/ } has many manuals. For each manual they have photos of the machine to aid in it's identification.
Sometimes we use manuals for other brands of machines that actually match the ones we have in lieu of one with the correct name. Lots of different Japanese machines are badged differently, but are otherwise identical.
Good Luck.
Joe