I believe I have information on the Henry Hammerstrom you are asking about. His father was Andrew Hammerstrom, who changed his name upon immigration from Anders Jonasson. Anders' brother was Johan Jonasson, who was my great-grandfather. Mary who had replied once before me, is also a great-granddaughter of Johan.
I also noticed that you had posted on the Tolan message board, and after doing some research in the census records, came to the conclusion that Henry's wife Tillie's maiden name is Tolan - correct?
If this at all sounds familiar or correct, please respond!