1. If you want to remove the slippery inner hexagon screw, you can also use the screw head of the inner hexagon screw of the saw blade to saw back to make the screw head extrude a flat gap, and then use the saw blade to unscrew the inner hexagon screw with a zigzag screwdriver. 
If the screw is too tight, you can also hit the screwdriver continuously with a hammer to make the screw fall off. 

2. If you want to remove the slipped inner hexagonal cylindrical head screw, you should first insert a screwdriver of appropriate size into the relative angle of the inner hexagonal cylindrical head screw, then tighten the screw, and then fix it with AB glue, wait for about half an hour, you can remove the inner hexagonal screw. 

3. If you want to remove the inner hexagon screw that has been slipped, you can also glue the wrench directly to the bolt. 
The bonding part of the fire-baked adhesive becomes brittle after being heated, and the wrench can be taken out.