There isn't a lot of activity on the group right now, so I thought I would start another thread to make sure you saw the subject.
On Feb 7, 8:00 pm, Kevin Miller >
Kevin - my disk sander disk wasn't true either. I am not sure what happened... did I bang into it with something, did the metal move around... did I overheat the disk.... I don't know. But it didn't show up when I had 60 grit on it, but I got burned >spots< when I went to 120.
I looked at my disk and found it to be a medium hard aluminum, so I was set on how to fix it. Here's how I did it.
I cleaned off the remaining gum from the disk after removiing the sandpaper. Got it as clean as I could. Nothing there now but bare aluminum. I made sure the disk was tight on its shaft. Then I put the framing square up the the disk as a straight edge and spun it around by hand, marking with a large (dime sized) dot where the disk hit the square. It is important here that you put the square arcross the whole disk at once so you won't bevel your disk.
Adjust the table up to the disk, less than 1/8" away from the wheel, or to where it barely spins freely.
Turn on the sander. I used my favorite round scraper (1/2" X1" in this case with no burr) and eased up to the rotating black dots. I tried to keep the height of the cutting edge at or just below center and cut on the downward side. This was easily accomplished by adjusting the table before I began.
Taking tiny cuts, it was a piece of cake. That pot metal aluminum came off of there like I had put it in a metal lathe. I wound up trueing the whole disk and the sander actually ran smoother, presumably because the disk (8") is running more true to the shaft.
This worked like a champ for me and was really easy. Hope you give this a whirl.
Robert