I made it at TechShop http://www.techshop.ws
If you have a 1/3 sheet or 1/4 sheet finish sander, then you know that pre-cut sheets of sandpaper can be purchased, but how many times have you cut your own from a full sheet? You probably cut it crooked with a utility knife, dulled your scissors, or tore the sheet.
Well not any more. Now you can easily cut perfectly straight 1/4, 1/3 or 1/2 sheets every time.
Scrap 3/4" plywood, particle board or MDF
(1) 10" hacksaw blade (longer blades can be used, but you will need to adjust the design to fit.)
(2) #6 x 3/4" round head wood screws
Laser engraver/cutter (available at TechShop)
Step 1: Layout
Sketch a layout, such as the one shown in this step, to mark the proper sizes for the different size sheets, relative to the cutting edge of the saw blade.
To save yourself a step, you can also download our .DXF and CorelDRAW files at http://www.lime3D.net/instructables/sandpaper_cutter.zip