A picture would help as Singer made many machines of different models over lots of years.
There is a good site to help identify early Singer sewing machines can be found at
https://www.sandman-collectibles.com...r-machines.htm
I'm going to guess that it is a 128K, probably from about 1918. The K in 128K, just indicates that it was made at Kilbowie in Scotland.
Janey - Neat people never make the exciting discoveries I do.