I have the Porter Cable DA polisher and I have used it many times on many cars with no issues. I picked it up today to give a car a quick touch up on the hood scoop and I had a 3" backing plate on it, no counterweight. I took off the 3" backing plate tried to put the counterweight on but the screw holes wouldn't line up at all. The inner curve of the counterweight is too small now and it doesn't square up with the machine. The last time I used it I had a 5 inch backing plate + counterweight and then took them both off to use my 3" pads. I'm guessing the counterweight was still hot when I removed it and as it cooled, it warped.
Any other possible causes? Have you had a similar issue?
Any other possible causes? Have you had a similar issue?