This eBook will be cheap insurance when it comes to sanding your wood floors. This is a must read before you pick up that floor sander. It may save your floor from a fate worse than death. When pulling around that heavy floor sander, you need to think about gouging or sanding your floor unevenly, I will teach you how to make a perfectly flat floor.
I always start off by going over the whole floor on my hands and knees. This is only way to check an old floor for split boards and broken top grooves. I may find at this point that the floor is just too thin or damaged to handle the extensive sanding process that a stained floor needs.
Besides the rental drum sander cannot be tuned up like I am about to instruct, and will always cause "chatter" marks. These will show up as stripes across the grain of the boards once you stain, and by then it's too late. These rental machines are just too lightweight to do a decent job. And it does take months of training to use a floor sander without gouging your fine wood floor.
Set any protruding nails at this point and do any repairs of split boards. But don't fill all the nail holes at this point. If you apply a stain on numerous filled holes, these will turn quite dark, almost black. This may give the floor a peppered look if there are too many. Fill the holes after the stain and at least one coat of finish is on the floor.
I will fill any gaps (not holes) at this point, and it would be best to use dark filler if the floor will be darkly stained. Wood filler in any gaps will crack out eventually, and the floor will look better in the future if the filler is dark all the way through. New floors should have few if any gaps, and an older floor to be stained should be in quite good shape also, so this would be a minor filling.
After 36 and 60 the next-grit of sandpaper will be 80-grit, and then the last pass with the large drum machine will be done with burnished 80-grit. Or you can use 100 or 120, but I prefer to burnish the 80-grit on the drum.
Now you'll notice that I haven't even mentioned the edges yet. There is good reason for this. I will do all my edging only when I have completed the drum sanding, this avoids having any sanding-grit get under the drum sander. This can create deep scratch lines in the middle of the floor during the final sanding.
Sanding down your wood floor will remove scratches, nicks and indents. When you sand your wood floor, you are restoring its beauty. A floor with scratches looks worn and less elegant than a floor without scratches. Sanding also increases the longevity of the wood floor. A floor with scratches will be prone to have dirt rest in the grooves of a scratch. This makes the scratch susceptible to growing when the dirt moves around.