Julius3E8 and I had exchanged a couple of texts.  I like his design because it was easy and efficient, but occasionally the blade could move and start to slide out.  Julius3E8 solved this with a dab of superglue, which is probably smarter and easier than the time I spent.   But ...an engineer with a bone is a hard thing to give up.  I imported Julius3E8's original design into openscad and added a tongue with a tab to drop into the hole of an (American) razor blade.  It appears to keep the blade from sliding, and the openscad file is parameterized for "easy reading".  I did something I don't usually do.  I've included the g-code file.  This gives the orientation and supports that I found best for printing.  Note the slot for the blade is in the upward orientation, which left it more open and easier to pry apart.  I also printed at 0.2mm per layer (apart from first layer) which also seemed to work better. There's the tendency to want to print the scraper flat, but I found the orientation  in the gcode file to work best.  If someone can come up with an effective way to print it flat, please let me know and I'll try it out.