2 RG-6 cable fit nice and just right thru a 9/16' hole without any sleeve nor connectors on the end. But I won't push these thru a 9/16' hole more than 2" deep. When going deeper I always go to 3/4". And when going thru concrete, I use an electric hammer drill with SDS type bits. I would avoid tying to start small then ream out to larger when drilling concrete with a hammer drill because it will continually bind up.