I took apart my paper cutter and didn't draw a diagram. Foolish! Is there a manual available with a diagram of the assembly of the parts?
I couldn't find a manual. Can you make out how it goes together by looking at images on google? Or maybe this video: www.youtube.com/
This is a page about sharpening a paper cutter. Keeping the blades of a paper cutter sharp will ensure straight, clean cuts.
