So, I apparently the guy who gave me my 15t rear cog bench ground off some rust to make it look shiny, well as a result he bench ground a little bit of the little gap filler on the side of the cog so it doesn't sit flush with the lock ring anymore.

SO! I bought a new cog. Problem is the bike store only had 16t or higher, well my chainring was 42, and 42 16 is a little bit too easy SO, I thought, "hey I have a 52 cog at home!" so I asked him for an 18t cog.

I get home and I put the Chain ring on and find that if I put it on the inside of the chain ring holder thingy, the gear is too big and the chain rubs against the frame.

I put it to the outside and It looks like the chain line isn't perfect anymore.

My question is, how much angle is too much for a fixed? here is a picture of my two cogs:



Now, the picture isn't perfect, and it isn't quite edge on with the read cog, but it's pretty close, thankfully, it's not edge on slightly favors the chainline, but anyway, I added green lines to show where the two cogs are.

Is this too far?

What options do I have?

EDIT: Additionally, I have some other pictures with a chain laying over the cogs, and a second shot like this.