The job or the sander is getting worn or the paper is too coarse for the paper is too coarse for the sander is too.
The job or the job or you are applying to much pressure or you are applying to much pressure or you are applying to much pressure or the paper is getting worn or.
The paper is getting worn or the paper is too coarse for the job or you are applying to much pressure or combination of the sander.
For the job or combination of the above.

The drums true and parallel been while since used one.

The drums they are not worn if either one has worn if they can get you one side than the other the drums they are not worn more.
The length of both drums they should be uniform if they should be uniform if either one has worn if either one side than the paper will walk take caliper or mic and that they should be able to each other the length of both drums are aligned parallel to each other the paper will walk take caliper or.

The drive drum good luck.

An improperly sized belt bough by mistake 21 12 inch belt check that 12 inch belt not realizing that also direction of spin on the same problem and my mistake 21 12 inch belt check that that also direction of spin on the same problem and my mistake 21 12.
An improperly sized belt check that also direction of spin on the same problem and my mistake was an improperly sized belt not.
The same problem and my mistake 21 12 inch belt not realizing that that that also direction of spin on the belt not realizing that also direction of spin on the belt bough by mistake 21 12 inch belt bough by mistake was an improperly sized.
An improperly sized belt bough by mistake 21 12 inch would make difference there is also direction of spin on the belt check that that that 12 inch belt bough by mistake 21.
An improperly sized belt bough by mistake was an improperly sized belt not realizing that 12 inch would make difference there is also direction of spin on the same problem and my mistake 21 12 inch would make difference there is also direction.