Loose Junction Box?

You might be able to use "battleship" cut-in box holders that hold the box to the sheetrock. http://amzn.to/2jkyQSh

I don't see them on bug-box hardware store websites, I know our local True Value does carry them individually.

that is what these are for

http://www.acehardware.com/product/index.jsp?produ...

The angle won't matter.

dtstellwagomn: Again you prove you didn't READ the question, or you merely don't UNDERSTAND. This is NOT about installing a new box. It is about securing and existing box. Also note: The boxes you describe are EASIER to find at Lowe's, Home Depot, etc than ar True Value.

If you don't like me pointing out your BLATANT errors in this manner, unblock me so I can correct you in a comment to your incorrect answers.

You got it right. Use the phillips head grabber screws and it will be a piece of cake.

I am assuming that there are no wires in the box at this time or can be moved clear and protected. They make small grinding wheels for drills. Us one to make a starting spot for you drill. Drill your hole as best you can then screw it like you intended.

Don't grind to deep, just enough to give your drill a bite. You may have to start with a smaller drill bit and go slow. I have done it. It wasn't easy but worked.