Cooperman uses his self-built CNC machine for a variety of applications.  Amongst his interests is the cutting of vinyl signs.  In order to pursue this area of interest he has designed, built and documented this useful vinyl cutting knife.  The knife works very well as is evident in the images.

Along with  drawings for the knife there is also similar detail for a useful sharpening jig.  Click the image to access the construction details for this simple and effective addon.