I have had problems with the screw loosening also. I just keep checking it all the time while using it. One thing I have noticed when people use their cutters, is that they push their cut piece of fabric to the side after cutting, scraping it along the cutting mat. This will over time create flat spots on your blade. Then they wonder why it doesn't cut completely across next time. Also remember to close your cutter after each use. Even one drop on the floor (which I have done) will damage your BRAND NEW BLADE.