If you are in Georgia you can go to the main library of most any county and ask to look at the census which are on microfilm. They had them every ten years all way back to 1700's I believe. If you know the county your grandfather was born in you could look at the census for that county to see the first census he would have been in and find out who his parents were. For example if he was born in 1886 you would look at the 1890 census.

Many census years even have books that tell you the head of household names and where to look for them on the census microfilms. I know many times I had to go through every page of certain county microfilms looking for people which took hours to do.

If you are not in Georgia it is still possible that your main library might still have the ones from Georgia.