The File type generally used for filing keyways is:

screw slot file   Dan screw slot file

Find a screwdriver that FITS THE SLOT grind or file the screwdriver to fit if needed

File slots in small screws or narrow slots of any kind by using a screwhead with tang files These files come in three different thicknesses  What length screw for L-bracket with V-slot and T-nut? The 10mm M5 screw is used on the corner brackets if you don't file the tabs

battleground royale slot png Dremel wheels are for cutting off, and are neither square or rigid Screw slots should be cut with a saw, or a file, or in a mill Ideally they tip, Phillips tip and Hammer Type Screwdrivers available in this category Flat tip Screw Drivers are used to drive screws having rectangular slot