Kitchen sink strainer

I recently noticed my kitchen sink leaking at the bottom of the strainer. I've replaced it with two different new strainers and both leak. This is the first time I've done this. I don't know if I'm over tightening the nut. Could that be the problem? I've looked at the opening and there's nothing wrong with it. No dents or chips. Any help would be appreciated.

 

No, I don't think you can overtighten. Well I suppose you could... if you overtighten you would probably break the lock ring.

Generally you put either a ring of plumbers putty on the sink and press the strainer basket into it... or you use silicone. Then put the rubber washer on the bottom, then the paper washer, then the lock ring gets tightened while you hold the strainer basket stationary with a tool so it can't spin as you tighten the lock ring. If you used plumbers putty and it still leaks, try silicone.

Is it leaking around the perimeter of the strainer or where the pipe attaches?

Because if it is leaking where your tailpiece attaches, could it be that you are missing the washer there?

example

 

It's leaking from the strainer. The first time i used plumbers putty and then I found a rubber gasket
that's used so you don't have to use plumbers putty. Although when I used the plumbers putty, the strainer
did move. So i guess the putty might have had a split in it.

 

Make sure you follow the installation instructions and use the paper/cardboard washer. It's needed underneath the nut to reduce friction when tightening the nut.

 

This style doesn't leak so this is the only style I'll use any more.

https://www.lowes.com/pd/Keeney-3-5-...cluded/3132177

 

That style is easier to install than the type with one big nut which can be a challenge to tighten when working solo.