This article is from Issue 109 of Woodcraft Magazine.
I purchase sandpaper in 100 sheet sleeves. This saves some money, and allows me to size it as needed. To facilitate this, I made a cutter from a piece of scrap plywood and a hacksaw blade. I drew lines on the plywood corresponding to the sizes of paper I frequently need. The 4-1/2" and 5-1/2" lines allow me to quarter the sheets for a palm sander, and the 2-3/4" line gives me 1/ 8 sheets—a size I like to use when sanding on the lathe. To use the cutter, slide the paper under the blade and align it with the appropriate line. Then pull up to tear the paper neatly along the blade; no measuring required.
—Jim Kelly, Trappe, Pennsylvania