This sandpaper ripping jig is simple and cheap to build, and it will save you tons of time in the long run.
Standard sandpaper comes in 9 x 11 inch sheets. But this is rarely the size that I need. Most often, I end up dividing a sheet into smaller pieces to fit my sander or a sanding block. For a long time, I made do with simply folding the sandpaper and then tearing it. But this crude method often gave me less than satisfactory results. So I decided to come up with a more reliable way to do the job. See my DIY sandpaper cutter.