I didn't have to drill mine, but from what I recall when I did mine I just pushed the pin in, rotated the switch assembly and slid it out. Being that your pin is seized, I agree that you have to keep drilling until it's below the surface of the collar and then rotate the assembly and slide right. Keep drilling, but buy a quality bit( like one of those titanium coated ones) to speed the process along. You're doing great, just keep drilling.