If you`re afraid using tools without "flank drive" then you should stop immediately using open end wrenches (except with flank drive but then you`ll mar the bolt/screw) and stop using hex socket drivers and robertson/square tools.
Since a box end wrench don`t yield like a open end wrench the fastener always has 6 contact surfaces matching the exact parallel surfaces of the 12 point Hazet wrench.
Since a box end wrench don`t yield like a open end wrench the fastener always has 6 contact surfaces matching the exact parallel surfaces of the 12 point Hazet wrench.