Methods for floor sanding vary depending on the species, finish, and personal preference, but we’ll give an overview of sanding a typical oak floor with a polyurethane finish. A “rough cut” is made with a drum sander with 40 grit paper to remove finish and flatten the floor. To sand the edges of the floor the drum sander cannot reach, we use a disk sander called an edger which will do a pass with a 40 grit paper followed by an 80 grit. The drum sander then makes its final pass with 80 grit paper. We then use a random orbital sander to blend the area where the two previous machines met and remove any remaining sanding lines from the edger. Finish or unevenness in the corners is scraped out and sanded by hand. We then use a floor buffer with a 120 grit screen which serves to smooth out sanding lines and open the grain evenly. We then vacuum throughly before coating.